Baolin Wang [Fri, 14 Jan 2022 22:08:34 +0000 (14:08 -0800)]
mm: migrate: fix the return value of migrate_pages()
Patch series "Improve the migration stats".
According to talk with Zi Yan [1], this patch set changes the return
value of migrate_pages() to avoid returning a number which is larger
than the number of pages the users tried to migrate by move_pages()
syscall. Also fix the hugetlb migration stats and migration stats in
trace_mm_compaction_migratepages().
As Zi Yan pointed out, the syscall move_pages() can return a
non-migrated number larger than the number of pages the users tried to
migrate, when a THP page is failed to migrate. This is confusing for
users.
Since other migration scenarios do not care about the actual
non-migrated number of pages except the memory compaction migration
which will fix in following patch. Thus we can change the return value
to return the number of {normal page, THP, hugetlb} instead to avoid
this issue, and the number of THP splits will be considered as the
number of non-migrated THP, no matter how many subpages of the THP are
migrated successfully. Meanwhile we should still keep the migration
counters using the number of normal pages.
hugetlbfs: fix off-by-one error in hugetlb_vmdelete_list()
Pass "end - 1" instead of "end" when walking the interval tree in
hugetlb_vmdelete_list() to fix an inclusive vs. exclusive bug. The two
callers that pass a non-zero "end" treat it as exclusive, whereas the
interval tree iterator expects an inclusive "last". E.g. punching a
hole in a file that precisely matches the size of a single hugepage,
with a vma starting right on the boundary, will result in
unmap_hugepage_range() being called twice, with the second call having
start==end.
The off-by-one error doesn't cause functional problems as
__unmap_hugepage_range() turns into a massive nop due to
short-circuiting its for-loop on "address < end". But, the mmu_notifier
invocations to invalid_range_{start,end}() are passed a bogus zero-sized
range, which may be unexpected behavior for secondary MMUs.
The bug was exposed by commit ed922739c919 ("KVM: Use interval tree to
do fast hva lookup in memslots"), currently queued in the KVM tree for
5.17, which added a WARN to detect ranges with start==end.
Link: https://lkml.kernel.org/r/20211228234257.1926057-1-seanjc@google.com Fixes: 1bfad99ab425 ("hugetlbfs: hugetlb_vmtruncate_list() needs to take a range to delete") Signed-off-by: Sean Christopherson <seanjc@google.com> Reported-by: syzbot+4e697fe80a31aa7efe21@syzkaller.appspotmail.com Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jann Horn [Fri, 14 Jan 2022 22:08:27 +0000 (14:08 -0800)]
mm, oom: OOM sysrq should always kill a process
The OOM kill sysrq (alt+sysrq+F) should allow the user to kill the
process with the highest OOM badness with a single execution.
However, at the moment, the OOM kill can bail out if an OOM notifier
(e.g. the i915 one) says that it reclaimed a tiny amount of memory from
somewhere. That's probably not what the user wants, so skip the bailout
if the OOM was triggered via sysrq.
Link: https://lkml.kernel.org/r/20220106102605.635656-1-jannh@google.com Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Fri, 14 Jan 2022 22:08:24 +0000 (14:08 -0800)]
mm/mempolicy: fix all kernel-doc warnings
Fix kernel-doc warnings in mempolicy.c:
mempolicy.c:139: warning: No description found for return value of 'numa_map_to_online_node'
mempolicy.c:2165: warning: Excess function parameter 'node' description in 'alloc_pages_vma'
mempolicy.c:2973: warning: No description found for return value of 'mpol_parse_str'
This syscall can be used to set a home node for the MPOL_BIND and
MPOL_PREFERRED_MANY memory policy. Users should use this syscall after
setting up a memory policy for the specified range as shown below.
The syscall allows specifying a home node/preferred node from which
kernel will fulfill memory allocation requests first.
For address range with MPOL_BIND memory policy, if nodemask specifies
more than one node, page allocations will come from the node in the
nodemask with sufficient free memory that is closest to the home
node/preferred node.
For MPOL_PREFERRED_MANY if the nodemask specifies more than one node,
page allocation will come from the node in the nodemask with sufficient
free memory that is closest to the home node/preferred node. If there
is not enough memory in all the nodes specified in the nodemask, the
allocation will be attempted from the closest numa node to the home node
in the system.
This helps applications to hint at a memory allocation preference node
and fallback to _only_ a set of nodes if the memory is not available on
the preferred node. Fallback allocation is attempted from the node
which is nearest to the preferred node.
This helps applications to have control on memory allocation numa nodes
and avoids default fallback to slow memory NUMA nodes. For example a
system with NUMA nodes 1,2 and 3 with DRAM memory and 10, 11 and 12 of
slow memory
This will allocate from nodes closer to node 2 and will make sure the
kernel will only allocate from nodes 1, 2, and 3. Memory will not be
allocated from slow memory nodes 10, 11, and 12. This differs from
default MPOL_BIND behavior in that with default MPOL_BIND the allocation
will be attempted from node closer to the local node. One of the
reasons to specify a home node is to allow allocations from cpu less
NUMA node and its nearby NUMA nodes.
With MPOL_PREFERRED_MANY on the other hand will first try to allocate
from the closest node to node 2 from the node list 1, 2 and 3. If those
nodes don't have enough memory, kernel will allocate from slow memory
node 10, 11 and 12 which ever is closer to node 2.
Link: https://lkml.kernel.org/r/20211202123810.267175-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: <linux-api@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/mempolicy: use policy_node helper with MPOL_PREFERRED_MANY
Patch series "mm: add new syscall set_mempolicy_home_node", v6.
This patch (of 3):
A followup patch will enable setting a home node with
MPOL_PREFERRED_MANY memory policy. To facilitate that switch to using
policy_node helper. There is no functional change in this patch.
Link: https://lkml.kernel.org/r/20211202123810.267175-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20211202123810.267175-2-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: <linux-api@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Chen Wandun [Fri, 14 Jan 2022 22:08:10 +0000 (14:08 -0800)]
mm/page_isolation: unset migratetype directly for non Buddy page
In unset_migratetype_isolate(), we can bypass the call to
move_freepages_block() for non-buddy pages.
It will save a few cpu cycles for some situations such as cma and
hugetlb when allocating continue pages, in these situation function
alloc_contig_pages will be called.
alloc_contig_pages
__alloc_contig_migrate_range
isolate_freepages_range ==> pages has been remove from buddy
undo_isolate_page_range
unset_migratetype_isolate ==> can directly set migratetype
[osalvador@suse.de: changelog tweak]
Link: https://lkml.kernel.org/r/20211229033649.2760586-1-chenwandun@huawei.com Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock") Signed-off-by: Chen Wandun <chenwandun@huawei.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Wang Kefeng <wangkefeng.wang@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Gang Li [Fri, 14 Jan 2022 22:08:07 +0000 (14:08 -0800)]
vmscan: make drop_slab_node static
drop_slab_node is only used in drop_slab. So remove it's declaration
from header file and add keyword static for it's definition.
Link: https://lkml.kernel.org/r/20211111062445.5236-1-ligang.bdlg@bytedance.com Signed-off-by: Gang Li <ligang.bdlg@bytedance.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Kravetz [Fri, 14 Jan 2022 22:08:04 +0000 (14:08 -0800)]
userfaultfd/selftests: clean up hugetlb allocation code
The message for commit f5c73297181c ("userfaultfd/selftests: fix hugetlb
area allocations") says there is no need to create a hugetlb file in the
non-shared testing case. However, the commit did not actually change
the code to prevent creation of the file.
While it is technically true that there is no need to create and use a
hugetlb file in the case of non-shared-testing, it is useful. This is
because 'hole punching' of a hugetlb file has the potentially incorrect
side effect of also removing pages from private mappings. The
userfaultfd test relies on this side effect for removing pages from the
destination buffer during rounds of stress testing.
Remove the incomplete code that was added to deal with no hugetlb file.
Just keep the code that prevents reserves from being created for the
destination area.
Link: https://lkml.kernel.org/r/20220104021729.111006-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Axel Rasmussen <axelrasmussen@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Waiman Long [Fri, 14 Jan 2022 22:07:58 +0000 (14:07 -0800)]
selftests/vm: make charge_reserved_hugetlb.sh work with existing cgroup setting
The hugetlb cgroup reservation test charge_reserved_hugetlb.sh assume
that no cgroup filesystems are mounted before running the test. That is
not true in many cases. As a result, the test fails to run. Fix that
by querying the current cgroup mount setting and using the existing
cgroup setup instead before attempting to freshly mount a cgroup
filesystem.
Similar change is also made for hugetlb_reparenting_test.sh as well,
though it still has problem if cgroup v2 isn't used.
The patched test scripts were run on a centos 8 based system to verify
that they ran properly.
Link: https://lkml.kernel.org/r/20220106201359.1646575-1-longman@redhat.com Fixes: 29750f71a9b4 ("hugetlb_cgroup: add hugetlb_cgroup reservation tests") Signed-off-by: Waiman Long <longman@redhat.com> Acked-by: Mina Almasry <almasrymina@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yang Yang [Fri, 14 Jan 2022 22:07:55 +0000 (14:07 -0800)]
mm/vmstat: add events for THP max_ptes_* exceeds
There are interfaces to adjust max_ptes_none, max_ptes_swap,
max_ptes_shared values, see
/sys/kernel/mm/transparent_hugepage/khugepaged/.
But system administrator may not know which value is the best. So Add
those events to support adjusting max_ptes_* to suitable values.
For example, if default max_ptes_swap value causes too much failures,
and system uses zram whose IO is fast, administrator could increase
max_ptes_swap until THP_SCAN_EXCEED_SWAP_PTE not increase anymore.
Link: https://lkml.kernel.org/r/20211225094036.574157-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Saravanan D <saravanand@fb.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yosry Ahmed [Fri, 14 Jan 2022 22:07:52 +0000 (14:07 -0800)]
mm, hugepages: make memory size variable in hugepage-mremap selftest
The hugetlb vma mremap() test currently maps 1GB of memory to trigger
pmd sharing and make sure that 'unshare' path in mremap code works. The
test originally only mapped 10MB of memory (as specified by the header
comment) but was later modified to 1GB to tackle this case.
However, not all machines will have 1GB of memory to spare for this
test. Adding a mapping size arg will allow run_vmtest.sh to pass an
adequate mapping size, while allowing users to run the test
independently with arbitrary size mappings.
Link: https://lkml.kernel.org/r/20211124203805.3700355-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed <yosryahmed@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Mina Almasry <almasrymina@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mina Almasry [Fri, 14 Jan 2022 22:07:48 +0000 (14:07 -0800)]
hugetlb: add hugetlb.*.numa_stat file
For hugetlb backed jobs/VMs it's critical to understand the numa
information for the memory backing these jobs to deliver optimal
performance.
Currently this technically can be queried from /proc/self/numa_maps, but
there are significant issues with that. Namely:
1. Memory can be mapped or unmapped.
2. numa_maps are per process and need to be aggregated across all
processes in the cgroup. For shared memory this is more involved as
the userspace needs to make sure it doesn't double count shared
mappings.
3. I believe querying numa_maps needs to hold the mmap_lock which adds
to the contention on this lock.
For these reasons I propose simply adding hugetlb.*.numa_stat file,
which shows the numa information of the cgroup similarly to
memory.numa_stat.
On cgroup-v2:
cat /sys/fs/cgroup/unified/test/hugetlb.2MB.numa_stat
total=2097152 N0=2097152 N1=0
On cgroup-v1:
cat /sys/fs/cgroup/hugetlb/test/hugetlb.2MB.numa_stat
total=2097152 N0=2097152 N1=0
hierarichal_total=2097152 N0=2097152 N1=0
This patch was tested manually by allocating hugetlb memory and querying
the hugetlb.*.numa_stat file of the cgroup and its parents.
[colin.i.king@googlemail.com: fix spelling mistake "hierarichal" -> "hierarchical"] Link: https://lkml.kernel.org/r/20211125090635.23508-1-colin.i.king@gmail.com
[keescook@chromium.org: fix copy/paste array assignment] Link: https://lkml.kernel.org/r/20211203065647.2819707-1-keescook@chromium.org Link: https://lkml.kernel.org/r/20211123001020.4083653-1-almasrymina@google.com Signed-off-by: Mina Almasry <almasrymina@google.com> Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Jue Wang <juew@google.com> Cc: Yang Yao <ygyao@google.com> Cc: Joanna Li <joannali@google.com> Cc: Cannon Matthews <cannonmatthews@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The above failure happened when calling kmalloc() to allocate buffer with
GFP_DMA. It requests to allocate slab page from DMA zone while no managed
pages at all in there.
Because in the current kernel, dma-kmalloc will be created as long as
CONFIG_ZONE_DMA is enabled. However, kdump kernel of x86_64 doesn't have
managed pages on DMA zone since commit 6f599d84231f ("x86/kdump: Always
reserve the low 1M when the crashkernel option is specified"). The
failure can be always reproduced.
For now, let's mute the warning of allocation failure if requesting pages
from DMA zone while no managed pages.
[akpm@linux-foundation.org: fix warning]
Link: https://lkml.kernel.org/r/20211223094435.248523-4-bhe@redhat.com Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified") Signed-off-by: Baoquan He <bhe@redhat.com> Acked-by: John Donnelly <john.p.donnelly@oracle.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Baoquan He [Fri, 14 Jan 2022 22:07:41 +0000 (14:07 -0800)]
dma/pool: create dma atomic pool only if dma zone has managed pages
Currently three dma atomic pools are initialized as long as the relevant
kernel codes are built in. While in kdump kernel of x86_64, this is not
right when trying to create atomic_pool_dma, because there's no managed
pages in DMA zone. In the case, DMA zone only has low 1M memory
presented and locked down by memblock allocator. So no pages are added
into buddy of DMA zone. Please check commit f1d4d47c5851 ("x86/setup:
Always reserve the first 1M of RAM").
Then in kdump kernel of x86_64, it always prints below failure message:
DMA: preallocated 128 KiB GFP_KERNEL pool for atomic allocations
swapper/0: page allocation failure: order:5, mode:0xcc1(GFP_KERNEL|GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-0.rc5.20210611git929d931f2b40.42.fc35.x86_64 #1
Hardware name: Dell Inc. PowerEdge R910/0P658H, BIOS 2.12.0 06/04/2018
Call Trace:
dump_stack+0x7f/0xa1
warn_alloc.cold+0x72/0xd6
__alloc_pages_slowpath.constprop.0+0xf29/0xf50
__alloc_pages+0x24d/0x2c0
alloc_page_interleave+0x13/0xb0
atomic_pool_expand+0x118/0x210
__dma_atomic_pool_init+0x45/0x93
dma_atomic_pool_init+0xdb/0x176
do_one_initcall+0x67/0x320
kernel_init_freeable+0x290/0x2dc
kernel_init+0xa/0x111
ret_from_fork+0x22/0x30
Mem-Info:
......
DMA: failed to allocate 128 KiB GFP_KERNEL|GFP_DMA pool for atomic allocation
DMA: preallocated 128 KiB GFP_KERNEL|GFP_DMA32 pool for atomic allocations
Here, let's check if DMA zone has managed pages, then create
atomic_pool_dma if yes. Otherwise just skip it.
Link: https://lkml.kernel.org/r/20211223094435.248523-3-bhe@redhat.com Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified") Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: John Donnelly <john.p.donnelly@oracle.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: David Rientjes <rientjes@google.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
***Root cause:
In the current kernel, it assumes that DMA zone must have managed pages
and try to request pages if CONFIG_ZONE_DMA is enabled. While this is not
always true. E.g in kdump kernel of x86_64, only low 1M is presented and
locked down at very early stage of boot, so that this low 1M won't be
added into buddy allocator to become managed pages of DMA zone. This
exception will always cause page allocation failure if page is requested
from DMA zone.
***Investigation:
This failure happens since below commit merged into linus's tree. 1a6a9044b967 x86/setup: Remove CONFIG_X86_RESERVE_LOW and reservelow= options 23721c8e92f7 x86/crash: Remove crash_reserve_low_1M() f1d4d47c5851 x86/setup: Always reserve the first 1M of RAM 7c321eb2b843 x86/kdump: Remove the backup region handling 6f599d84231f x86/kdump: Always reserve the low 1M when the crashkernel option is specified
Before them, on x86_64, the low 640K area will be reused by kdump kernel.
So in kdump kernel, the content of low 640K area is copied into a backup
region for dumping before jumping into kdump. Then except of those firmware
reserved region in [0, 640K], the left area will be added into buddy
allocator to become available managed pages of DMA zone.
However, after above commits applied, in kdump kernel of x86_64, the low
1M is reserved by memblock, but not released to buddy allocator. So any
later page allocation requested from DMA zone will fail.
At the beginning, if crashkernel is reserved, the low 1M need be locked
down because AMD SME encrypts memory making the old backup region
mechanims impossible when switching into kdump kernel.
Later, it was also observed that there are BIOSes corrupting memory
under 1M. To solve this, in commit f1d4d47c5851, the entire region of
low 1M is always reserved after the real mode trampoline is allocated.
Besides, recently, Intel engineer mentioned their TDX (Trusted domain
extensions) which is under development in kernel also needs to lock down
the low 1M. So we can't simply revert above commits to fix the page allocation
failure from DMA zone as someone suggested.
***Solution:
Currently, only DMA atomic pool and dma-kmalloc will initialize and
request page allocation with GFP_DMA during bootup.
So only initializ DMA atomic pool when DMA zone has available managed
pages, otherwise just skip the initialization.
For dma-kmalloc(), for the time being, let's mute the warning of
allocation failure if requesting pages from DMA zone while no manged
pages. Meanwhile, change code to use dma_alloc_xx/dma_map_xx API to
replace kmalloc(GFP_DMA), or do not use GFP_DMA when calling kmalloc() if
not necessary. Christoph is posting patches to fix those under
drivers/scsi/. Finally, we can remove the need of dma-kmalloc() as people
suggested.
This patch (of 3):
In some places of the current kernel, it assumes that dma zone must have
managed pages if CONFIG_ZONE_DMA is enabled. While this is not always
true. E.g in kdump kernel of x86_64, only low 1M is presented and locked
down at very early stage of boot, so that there's no managed pages at all
in DMA zone. This exception will always cause page allocation failure if
page is requested from DMA zone.
Here add function has_managed_dma() and the relevant helper functions to
check if there's DMA zone with managed pages. It will be used in later
patches.
Link: https://lkml.kernel.org/r/20211223094435.248523-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20211223094435.248523-2-bhe@redhat.com Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified") Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: John Donnelly <john.p.donnelly@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Borislav Petkov <bp@alien8.de> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Miles Chen [Fri, 14 Jan 2022 22:07:30 +0000 (14:07 -0800)]
include/linux/gfp.h: further document GFP_DMA32
kmalloc(..., GFP_DMA32) does not return DMA32 memory because the DMA32
kmalloc cache array is not implemented. (Reason: there is no such user
in kernel).
Put a short comment about this so people can understand this by reading
the comment.
Michal Hocko [Fri, 14 Jan 2022 22:07:27 +0000 (14:07 -0800)]
mm: drop node from alloc_pages_vma
alloc_pages_vma is meant to allocate a page with a vma specific memory
policy. The initial node parameter is always a local node so it is
pointless to waste a function argument for this. Drop the parameter.
Link: https://lkml.kernel.org/r/YaSnlv4QpryEpesG@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Xiongwei Song [Fri, 14 Jan 2022 22:07:24 +0000 (14:07 -0800)]
mm: page_alloc: fix building error on -Werror=array-compare
Arthur Marsh reported we would hit the error below when building kernel
with gcc-12:
CC mm/page_alloc.o
mm/page_alloc.c: In function `mem_init_print_info':
mm/page_alloc.c:8173:27: error: comparison between two arrays [-Werror=array-compare]
8173 | if (start <= pos && pos < end && size > adj) \
|
In C++20, the comparision between arrays should be warned.
Link: https://lkml.kernel.org/r/20211125130928.32465-1-sxwjean@me.com Signed-off-by: Xiongwei Song <sxwjean@gmail.com> Reported-by: Arthur Marsh <arthur.marsh@internode.on.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/pagealloc: sysctl: change watermark_scale_factor max limit to 30%
For embedded systems with low total memory, having to run applications
with relatively large memory requirements, 10% max limitation for
watermark_scale_factor poses an issue of triggering direct reclaim every
time such application is started. This results in slow application
startup times and bad end-user experience.
By increasing watermark_scale_factor max limit we allow vendors more
flexibility to choose the right level of kswapd aggressiveness for their
device and workload requirements.
Link: https://lkml.kernel.org/r/20211124193604.2758863-1-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Lukas Middendorf <kernel@tuxforce.de> Cc: Antti Palosaari <crope@iki.fi> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Zhang Yi <yi.zhang@huawei.com> Cc: Fengfei Xi <xi.fengfei@h3c.com> Cc: Mike Rapoport <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
NeilBrown [Fri, 14 Jan 2022 22:07:14 +0000 (14:07 -0800)]
mm: introduce memalloc_retry_wait()
Various places in the kernel - largely in filesystems - respond to a
memory allocation failure by looping around and re-trying. Some of
these cannot conveniently use __GFP_NOFAIL, for reasons such as:
- a GFP_ATOMIC allocation, which __GFP_NOFAIL doesn't work on
- a need to check for the process being signalled between failures
- the possibility that other recovery actions could be performed
- the allocation is quite deep in support code, and passing down an
extra flag to say if __GFP_NOFAIL is wanted would be clumsy.
Many of these currently use congestion_wait() which (in almost all
cases) simply waits the given timeout - congestion isn't tracked for
most devices.
It isn't clear what the best delay is for loops, but it is clear that
the various filesystems shouldn't be responsible for choosing a timeout.
This patch introduces memalloc_retry_wait() with takes on that
responsibility. Code that wants to retry a memory allocation can call
this function passing the GFP flags that were used. It will wait
however is appropriate.
For now, it only considers __GFP_NORETRY and whatever
gfpflags_allow_blocking() tests. If blocking is allowed without
__GFP_NORETRY, then alloc_page either made some reclaim progress, or
waited for a while, before failing. So there is no need for much
further waiting. memalloc_retry_wait() will wait until the current
jiffie ends. If this condition is not met, then alloc_page() won't have
waited much if at all. In that case memalloc_retry_wait() waits about
200ms. This is the delay that most current loops uses.
linux/sched/mm.h needs to be included in some files now,
but linux/backing-dev.h does not.
Link: https://lkml.kernel.org/r/163754371968.13692.1277530886009912421@noble.neil.brown.name Signed-off-by: NeilBrown <neilb@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Chao Yu <chao@kernel.org> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Fri, 14 Jan 2022 22:07:11 +0000 (14:07 -0800)]
mm: make slab and vmalloc allocators __GFP_NOLOCKDEP aware
sl?b and vmalloc allocators reduce the given gfp mask for their internal
needs. For that they use GFP_RECLAIM_MASK to preserve the reclaim
behavior and constrains.
__GFP_NOLOCKDEP is not a part of that mask because it doesn't really
control the reclaim behavior strictly speaking. On the other hand it
tells the underlying page allocator to disable reclaim recursion
detection so arguably it should be part of the mask.
Having __GFP_NOLOCKDEP in the mask will not alter the behavior in any
form so this change is safe pretty much by definition. It also adds a
support for this flag to SL?B and vmalloc allocators which will in turn
allow its use to kvmalloc as well. A lack of the support has been
noticed recently in
Michal Hocko [Fri, 14 Jan 2022 22:07:07 +0000 (14:07 -0800)]
mm: allow !GFP_KERNEL allocations for kvmalloc
Support for GFP_NO{FS,IO} and __GFP_NOFAIL has been implemented by
previous patches so we can allow the support for kvmalloc. This will
allow some external users to simplify or completely remove their
helpers.
GFP_NOWAIT semantic hasn't been supported so far but it hasn't been
explicitly documented so let's add a note about that.
ceph_kvmalloc is the first helper to be dropped and changed to kvmalloc.
Link: https://lkml.kernel.org/r/20211122153233.9924-5-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Neil Brown <neilb@suse.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Fri, 14 Jan 2022 22:07:04 +0000 (14:07 -0800)]
mm/vmalloc: be more explicit about supported gfp flags.
Commit b7d90e7a5ea8 ("mm/vmalloc: be more explicit about supported gfp
flags") has been merged prematurely without the rest of the series and
without addressed review feedback from Neil. Fix that up now. Only
wording is changed slightly.
Link: https://lkml.kernel.org/r/20211122153233.9924-4-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Neil Brown <neilb@suse.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Fri, 14 Jan 2022 22:07:01 +0000 (14:07 -0800)]
mm/vmalloc: add support for __GFP_NOFAIL
Dave Chinner has mentioned that some of the xfs code would benefit from
kvmalloc support for __GFP_NOFAIL because they have allocations that
cannot fail and they do not fit into a single page.
The large part of the vmalloc implementation already complies with the
given gfp flags so there is no work for those to be done. The area and
page table allocations are an exception to that. Implement a retry loop
for those.
Add a short sleep before retrying. 1 jiffy is a completely random
timeout. Ideally the retry would wait for an explicit event - e.g. a
change to the vmalloc space change if the failure was caused by the
space fragmentation or depletion. But there are multiple different
reasons to retry and this could become much more complex. Keep the
retry simple for now and just sleep to prevent from hogging CPUs.
Link: https://lkml.kernel.org/r/20211122153233.9924-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Neil Brown <neilb@suse.de> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Fri, 14 Jan 2022 22:06:57 +0000 (14:06 -0800)]
mm/vmalloc: alloc GFP_NO{FS,IO} for vmalloc
Patch series "extend vmalloc support for constrained allocations", v2.
Based on a recent discussion with Dave and Neil [1] I have tried to
implement NOFS, NOIO, NOFAIL support for the vmalloc to make life of
kvmalloc users easier.
A requirement for NOFAIL support for kvmalloc was new to me but this
seems to be really needed by the xfs code.
NOFS/NOIO was a known and a long term problem which was hoped to be
handled by the scope API. Those scope should have been used at the
reclaim recursion boundaries both to document them and also to remove
the necessity of NOFS/NOIO constrains for all allocations within that
scope. Instead workarounds were developed to wrap a single allocation
instead (like ceph_kvmalloc).
First patch implements NOFS/NOIO support for vmalloc. The second one
adds NOFAIL support and the third one bundles all together into kvmalloc
and drops ceph_kvmalloc which can use kvmalloc directly now.
vmalloc historically hasn't supported GFP_NO{FS,IO} requests because
page table allocations do not support externally provided gfp mask and
performed GFP_KERNEL like allocations.
Since few years we have scope (memalloc_no{fs,io}_{save,restore}) APIs
to enforce NOFS and NOIO constrains implicitly to all allocators within
the scope. There was a hope that those scopes would be defined on a
higher level when the reclaim recursion boundary starts/stops (e.g.
when a lock required during the memory reclaim is required etc.). It
seems that not all NOFS/NOIO users have adopted this approach and
instead they have taken a workaround approach to wrap a single
[k]vmalloc allocation by a scope API.
These workarounds do not serve the purpose of a better reclaim recursion
documentation and reduction of explicit GFP_NO{FS,IO} usege so let's
just provide them with the semantic they are asking for without a need
for workarounds.
Add support for GFP_NOFS and GFP_NOIO to vmalloc directly. All internal
allocations already comply with the given gfp_mask. The only current
exception is vmap_pages_range which maps kernel page tables. Infer the
proper scope API based on the given gfp mask.
[sfr@canb.auug.org.au: mm/vmalloc.c needs linux/sched/mm.h] Link: https://lkml.kernel.org/r/20211217232641.0148710c@canb.auug.org.au Link: https://lkml.kernel.org/r/20211122153233.9924-1-mhocko@kernel.org Link: https://lkml.kernel.org/r/20211122153233.9924-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Neil Brown <neilb@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Ilya Dryomov <idryomov@gmail.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Dave Chinner <dchinner@redhat.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Christian König [Fri, 14 Jan 2022 22:06:54 +0000 (14:06 -0800)]
mm/dmapool.c: revert "make dma pool to use kmalloc_node"
This reverts commit 2618c60b8b5836 ("dma: make dma pool to use
kmalloc_node").
While working myself into the dmapool code I've found this little odd
kmalloc_node().
What basically happens here is that we allocate the housekeeping
structure on the numa node where the device is attached to. Since the
device is never doing DMA to or from that memory this doesn't seem to
make sense at all.
So while this doesn't seem to cause much harm it's probably cleaner to
revert the change for consistency.
Link: https://lkml.kernel.org/r/20211221110724.97664-1-christian.koenig@amd.com Signed-off-by: Christian König <christian.koenig@amd.com> Cc: Yinghai Lu <yinghai.lu@sun.com> Cc: Andi Kleen <ak@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pasha Tatashin [Fri, 14 Jan 2022 22:06:37 +0000 (14:06 -0800)]
mm: page table check
Check user page table entries at the time they are added and removed.
Allows to synchronously catch memory corruption issues related to double
mapping.
When a pte for an anonymous page is added into page table, we verify
that this pte does not already point to a file backed page, and vice
versa if this is a file backed page that is being added we verify that
this page does not have an anonymous mapping
We also enforce that read-only sharing for anonymous pages is allowed
(i.e. cow after fork). All other sharing must be for file pages.
Page table check allows to protect and debug cases where "struct page"
metadata became corrupted for some reason. For example, when refcnt or
mapcount become invalid.
Link: https://lkml.kernel.org/r/20211221154650.1047963-4-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wei Xu <weixugc@google.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pasha Tatashin [Fri, 14 Jan 2022 22:06:33 +0000 (14:06 -0800)]
mm: ptep_clear() page table helper
We have ptep_get_and_clear() and ptep_get_and_clear_full() helpers to
clear PTE from user page tables, but there is no variant for simple
clear of a present PTE from user page tables without using a low level
pte_clear() which can be either native or para-virtualised.
Add a new ptep_clear() that can be used in common code to clear PTEs
from page table. We will need this call later in order to add a hook
for page table check.
Link: https://lkml.kernel.org/r/20211221154650.1047963-3-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <keescook@chromium.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wei Xu <weixugc@google.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pasha Tatashin [Fri, 14 Jan 2022 22:06:29 +0000 (14:06 -0800)]
mm: change page type prior to adding page table entry
Patch series "page table check", v3.
Ensure that some memory corruptions are prevented by checking at the
time of insertion of entries into user page tables that there is no
illegal sharing.
We have recently found a problem [1] that existed in kernel since 4.14.
The problem was caused by broken page ref count and led to memory
leaking from one process into another. The problem was accidentally
detected by studying a dump of one process and noticing that one page
contains memory that should not belong to this process.
There are some other page->_refcount related problems that were recently
fixed: [2], [3] which potentially could also lead to illegal sharing.
In addition to hardening refcount [4] itself, this work is an attempt to
prevent this class of memory corruption issues.
It uses a simple state machine that is independent from regular MM logic
to check for illegal sharing at time pages are inserted and removed from
page tables.
There are a few places where we first update the entry in the user page
table, and later change the struct page to indicate that this is
anonymous or file page.
In most places, however, we first configure the page metadata and then
insert entries into the page table. Page table check, will use the
information from struct page to verify the type of entry is inserted.
Change the order in all places to first update struct page, and later to
update page table.
This means that we first do calls that may change the type of page (anon
or file):
Shuah Khan [Fri, 14 Jan 2022 22:06:26 +0000 (14:06 -0800)]
docs/vm: add vmalloced-kernel-stacks document
Add a new document to explain Virtually Mapped Kernel Stack Support.
This is a compilation of information from the code and original patch
series that introduced the Virtually Mapped Kernel Stacks feature.
This document summarizes the feature and provides details on allocation,
free, and stack overflow handling. Provides reference to available
tests.
Link: https://lkml.kernel.org/r/20211215002004.47981-1-skhan@linuxfoundation.org Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Andy Lutomirski <luto@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/oom_kill: allow process_mrelease to run under mmap_lock protection
With exit_mmap holding mmap_write_lock during free_pgtables call,
process_mrelease does not need to elevate mm->mm_users in order to
prevent exit_mmap from destrying pagetables while __oom_reap_task_mm is
walking the VMA tree. The change prevents process_mrelease from calling
the last mmput, which can lead to waiting for IO completion in exit_aio.
Link: https://lkml.kernel.org/r/20211209191325.3069345-3-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Christian Brauner <christian@brauner.io> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: Jan Engelhardt <jengelh@inai.de> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tim Murray <timmurray@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: protect free_pgtables with mmap_lock write lock in exit_mmap
oom-reaper and process_mrelease system call should protect against races
with exit_mmap which can destroy page tables while they walk the VMA
tree. oom-reaper protects from that race by setting MMF_OOM_VICTIM and
by relying on exit_mmap to set MMF_OOM_SKIP before taking and releasing
mmap_write_lock. process_mrelease has to elevate mm->mm_users to
prevent such race.
Both oom-reaper and process_mrelease hold mmap_read_lock when walking
the VMA tree. The locking rules and mechanisms could be simpler if
exit_mmap takes mmap_write_lock while executing destructive operations
such as free_pgtables.
Change exit_mmap to hold the mmap_write_lock when calling unlock_range,
free_pgtables and remove_vma. Note also that because oom-reaper checks
VM_LOCKED flag, unlock_range() should not be allowed to race with it.
Before this patch, remove_vma used to be called with no locks held,
however with fput being executed asynchronously and vm_ops->close not
being allowed to hold mmap_lock (it is called from __split_vma with
mmap_sem held for write), changing that should be fine.
In most cases this lock should be uncontended. Previously, Kirill
reported ~4% regression caused by a similar change [1]. We reran the
same test and although the individual results are quite noisy, the
percentiles show lower regression with 1.6% being the worst case [2].
The change allows oom-reaper and process_mrelease to execute safely
under mmap_read_lock without worries that exit_mmap might destroy page
tables from under them.
Arnd Bergmann [Fri, 14 Jan 2022 22:06:10 +0000 (14:06 -0800)]
mm: move tlb_flush_pending inline helpers to mm_inline.h
linux/mm_types.h should only define structure definitions, to make it
cheap to include elsewhere. The atomic_t helper function definitions
are particularly large, so it's better to move the helpers using those
into the existing linux/mm_inline.h and only include that where needed.
As a follow-up, we may want to go through all the indirect includes in
mm_types.h and reduce them as much as possible.
Link: https://lkml.kernel.org/r/20211207125710.2503446-2-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Colin Cross <ccross@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Yu Zhao <yuzhao@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Arnd Bergmann [Fri, 14 Jan 2022 22:06:07 +0000 (14:06 -0800)]
mm: move anon_vma declarations to linux/mm_inline.h
The patch to add anonymous vma names causes a build failure in some
configurations:
include/linux/mm_types.h: In function 'is_same_vma_anon_name':
include/linux/mm_types.h:924:37: error: implicit declaration of function 'strcmp' [-Werror=implicit-function-declaration]
924 | return name && vma_name && !strcmp(name, vma_name);
| ^~~~~~
include/linux/mm_types.h:22:1: note: 'strcmp' is defined in header '<string.h>'; did you forget to '#include <string.h>'?
This should not really be part of linux/mm_types.h in the first place,
as that header is meant to only contain structure defintions and need a
minimum set of indirect includes itself.
While the header clearly includes more than it should at this point,
let's not make it worse by including string.h as well, which would pull
in the expensive (compile-speed wise) fortify-string logic.
Move the new functions into a separate header that only needs to be
included in a couple of locations.
Link: https://lkml.kernel.org/r/20211207125710.2503446-1-arnd@kernel.org Fixes: "mm: add a field to store names for private anonymous memory" Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@google.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While forking a process with high number (64K) of named anonymous vmas
the overhead caused by strdup() is noticeable. Experiments with ARM64
Android device show up to 40% performance regression when forking a
process with 64k unpopulated anonymous vmas using the max name lengths
vs the same process with the same number of anonymous vmas having no
name.
Introduce anon_vma_name refcounted structure to avoid the overhead of
copying vma names during fork() and when splitting named anonymous vmas.
When a vma is duplicated, instead of copying the name we increment the
refcount of this structure. Multiple vmas can point to the same
anon_vma_name as long as they increment the refcount. The name member
of anon_vma_name structure is assigned at structure allocation time and
is never changed. If vma name changes then the refcount of the original
structure is dropped, a new anon_vma_name structure is allocated to hold
the new name and the vma pointer is updated to point to the new
structure.
With this approach the fork() performance regressions is reduced 3-4x
times and with usecases using more reasonable number of VMAs (a few
thousand) the regressions is not measurable.
Link: https://lkml.kernel.org/r/20211019215511.3771969-3-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@google.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Glauber <jan.glauber@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rob Landley <rob@landley.net> Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com> Cc: Shaohua Li <shli@fusionio.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Colin Cross [Fri, 14 Jan 2022 22:05:59 +0000 (14:05 -0800)]
mm: add a field to store names for private anonymous memory
In many userspace applications, and especially in VM based applications
like Android uses heavily, there are multiple different allocators in
use. At a minimum there is libc malloc and the stack, and in many cases
there are libc malloc, the stack, direct syscalls to mmap anonymous
memory, and multiple VM heaps (one for small objects, one for big
objects, etc.). Each of these layers usually has its own tools to
inspect its usage; malloc by compiling a debug version, the VM through
heap inspection tools, and for direct syscalls there is usually no way
to track them.
On Android we heavily use a set of tools that use an extended version of
the logic covered in Documentation/vm/pagemap.txt to walk all pages
mapped in userspace and slice their usage by process, shared (COW) vs.
unique mappings, backing, etc. This can account for real physical
memory usage even in cases like fork without exec (which Android uses
heavily to share as many private COW pages as possible between
processes), Kernel SamePage Merging, and clean zero pages. It produces
a measurement of the pages that only exist in that process (USS, for
unique), and a measurement of the physical memory usage of that process
with the cost of shared pages being evenly split between processes that
share them (PSS).
If all anonymous memory is indistinguishable then figuring out the real
physical memory usage (PSS) of each heap requires either a pagemap
walking tool that can understand the heap debugging of every layer, or
for every layer's heap debugging tools to implement the pagemap walking
logic, in which case it is hard to get a consistent view of memory
across the whole system.
Tracking the information in userspace leads to all sorts of problems.
It either needs to be stored inside the process, which means every
process has to have an API to export its current heap information upon
request, or it has to be stored externally in a filesystem that somebody
needs to clean up on crashes. It needs to be readable while the process
is still running, so it has to have some sort of synchronization with
every layer of userspace. Efficiently tracking the ranges requires
reimplementing something like the kernel vma trees, and linking to it
from every layer of userspace. It requires more memory, more syscalls,
more runtime cost, and more complexity to separately track regions that
the kernel is already tracking.
This patch adds a field to /proc/pid/maps and /proc/pid/smaps to show a
userspace-provided name for anonymous vmas. The names of named
anonymous vmas are shown in /proc/pid/maps and /proc/pid/smaps as
[anon:<name>].
Userspace can set the name for a region of memory by calling
Setting the name to NULL clears it. The name length limit is 80 bytes
including NUL-terminator and is checked to contain only printable ascii
characters (including space), except '[',']','\','$' and '`'.
Ascii strings are being used to have a descriptive identifiers for vmas,
which can be understood by the users reading /proc/pid/maps or
/proc/pid/smaps. Names can be standardized for a given system and they
can include some variable parts such as the name of the allocator or a
library, tid of the thread using it, etc.
The name is stored in a pointer in the shared union in vm_area_struct
that points to a null terminated string. Anonymous vmas with the same
name (equivalent strings) and are otherwise mergeable will be merged.
The name pointers are not shared between vmas even if they contain the
same name. The name pointer is stored in a union with fields that are
only used on file-backed mappings, so it does not increase memory usage.
CONFIG_ANON_VMA_NAME kernel configuration is introduced to enable this
feature. It keeps the feature disabled by default to prevent any
additional memory overhead and to avoid confusing procfs parsers on
systems which are not ready to support named anonymous vmas.
The patch is based on the original patch developed by Colin Cross, more
specifically on its latest version [1] posted upstream by Sumit Semwal.
It used a userspace pointer to store vma names. In that design, name
pointers could be shared between vmas. However during the last
upstreaming attempt, Kees Cook raised concerns [2] about this approach
and suggested to copy the name into kernel memory space, perform
validity checks [3] and store as a string referenced from
vm_area_struct.
One big concern is about fork() performance which would need to strdup
anonymous vma names. Dave Hansen suggested experimenting with
worst-case scenario of forking a process with 64k vmas having longest
possible names [4]. I ran this experiment on an ARM64 Android device
and recorded a worst-case regression of almost 40% when forking such a
process.
This regression is addressed in the followup patch which replaces the
pointer to a name with a refcounted structure that allows sharing the
name pointer between vmas of the same name. Instead of duplicating the
string during fork() or when splitting a vma it increments the refcount.
Changes for prctl(2) manual page (in the options section):
PR_SET_VMA
Sets an attribute specified in arg2 for virtual memory areas
starting from the address specified in arg3 and spanning the
size specified in arg4. arg5 specifies the value of the attribute
to be set. Note that assigning an attribute to a virtual memory
area might prevent it from being merged with adjacent virtual
memory areas due to the difference in that attribute's value.
Currently, arg2 must be one of:
PR_SET_VMA_ANON_NAME
Set a name for anonymous virtual memory areas. arg5 should
be a pointer to a null-terminated string containing the
name. The name length including null byte cannot exceed
80 bytes. If arg5 is NULL, the name of the appropriate
anonymous virtual memory areas will be reset. The name
can contain only printable ascii characters (including
space), except '[',']','\','$' and '`'.
This feature is available only if the kernel is built with
the CONFIG_ANON_VMA_NAME option enabled.
[surenb@google.com: docs: proc.rst: /proc/PID/maps: fix malformed table] Link: https://lkml.kernel.org/r/20211123185928.2513763-1-surenb@google.com
[surenb: rebased over v5.15-rc6, replaced userpointer with a kernel copy,
added input sanitization and CONFIG_ANON_VMA_NAME config. The bulk of the
work here was done by Colin Cross, therefore, with his permission, keeping
him as the author]
Link: https://lkml.kernel.org/r/20211019215511.3771969-2-surenb@google.com Signed-off-by: Colin Cross <ccross@google.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Glauber <jan.glauber@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rob Landley <rob@landley.net> Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com> Cc: Shaohua Li <shli@fusionio.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Colin Cross [Fri, 14 Jan 2022 22:05:55 +0000 (14:05 -0800)]
mm: rearrange madvise code to allow for reuse
Patch series "mm: rearrange madvise code to allow for reuse", v11.
Avoid performance regression of the new anon vma name field refcounting it.
I checked the image sizes with allnoconfig builds:
unpatched Linus' ToT
text data bss dec hex filename 1324759 32 73928 1398719 1557bf vmlinux
After the first patch is applied (madvise refactoring)
text data bss dec hex filename 1322346 32 73928 1396306 154e52 vmlinux
>>> 2413 bytes decrease vs ToT <<<
After all patches applied with CONFIG_ANON_VMA_NAME=n
text data bss dec hex filename 1322337 32 73928 1396297 154e49 vmlinux
>>> 2422 bytes decrease vs ToT <<<
After all patches applied with CONFIG_ANON_VMA_NAME=y
text data bss dec hex filename 1325228 32 73928 1399188 155994 vmlinux
>>> 469 bytes increase vs ToT <<<
This patch (of 3):
Refactor the madvise syscall to allow for parts of it to be reused by a
prctl syscall that affects vmas.
Move the code that walks vmas in a virtual address range into a function
that takes a function pointer as a parameter. The only caller for now
is sys_madvise, which uses it to call madvise_vma_behavior on each vma,
but the next patch will add an additional caller.
Move handling all vma behaviors inside madvise_behavior, and rename it
to madvise_vma_behavior.
Move the code that updates the flags on a vma, including splitting or
merging the vma as necessary, into a new function called
madvise_update_vma. The next patch will add support for updating a new
anon_name field as well.
Link: https://lkml.kernel.org/r/20211019215511.3771969-1-surenb@google.com Signed-off-by: Colin Cross <ccross@google.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jan Glauber <jan.glauber@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Rob Landley <rob@landley.net> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Kees Cook <keescook@chromium.org> Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com> Cc: David Rientjes <rientjes@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Shaohua Li <shli@fusionio.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Qi Zheng [Fri, 14 Jan 2022 22:05:51 +0000 (14:05 -0800)]
mm: remove redundant check about FAULT_FLAG_ALLOW_RETRY bit
Since commit 4064b9827063 ("mm: allow VM_FAULT_RETRY for multiple
times") allowed VM_FAULT_RETRY for multiple times, the
FAULT_FLAG_ALLOW_RETRY bit of fault_flag will not be changed in the page
fault path, so the following check is no longer needed:
flags & FAULT_FLAG_ALLOW_RETRY
So just remove it.
[akpm@linux-foundation.org: coding style fixes]
Link: https://lkml.kernel.org/r/20211110123358.36511-1-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Kirill Shutemov <kirill@shutemov.name> Cc: Peter Xu <peterx@redhat.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Shakeel Butt [Fri, 14 Jan 2022 22:05:45 +0000 (14:05 -0800)]
memcg: add per-memcg vmalloc stat
The kvmalloc* allocation functions can fallback to vmalloc allocations
and more often on long running machines. In addition the kernel does
have __GFP_ACCOUNT kvmalloc* calls. So, often on long running machines,
the memory.stat does not tell the complete picture which type of memory
is charged to the memcg. So add a per-memcg vmalloc stat.
Wang Weiyang [Fri, 14 Jan 2022 22:05:42 +0000 (14:05 -0800)]
mm/memcg: use struct_size() helper in kzalloc()
Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.
Link: https://github.com/KSPP/linux/issues/160 Link: https://lkml.kernel.org/r/20211216022024.127375-1-wangweiyang2@huawei.com Signed-off-by: Wang Weiyang <wangweiyang2@huawei.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Shakeel Butt [Fri, 14 Jan 2022 22:05:39 +0000 (14:05 -0800)]
memcg: better bounds on the memcg stats updates
Commit 11192d9c124d ("memcg: flush stats only if updated") added
tracking of memcg stats updates which is used by the readers to flush
only if the updates are over a certain threshold. However each
individual update can correspond to a large value change for a given
stat. For example adding or removing a hugepage to an LRU changes the
stat by thp_nr_pages (512 on x86_64).
Treating the update related to THP as one can keep the stat off, in
theory, by (thp_nr_pages * nr_cpus * CHARGE_BATCH) before flush.
To handle such scenarios, this patch adds consideration of the stat
update value as well instead of just the update event. In addition let
the asyn flusher unconditionally flush the stats to put time limit on
the stats skew and hopefully a lot less readers would need to flush.
Link: https://lkml.kernel.org/r/20211118065350.697046-1-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Michal Koutný" <mkoutny@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Schatzberg [Fri, 14 Jan 2022 22:05:35 +0000 (14:05 -0800)]
mm/memcg: add oom_group_kill memory event
Our container agent wants to know when a container exits if it was OOM
killed or not to report to the user. We use memory.oom.group = 1 to
ensure that OOM kills within the container's cgroup kill everything.
Existing memory.events are insufficient for knowing if this triggered:
1) Our current approach reads memory.events oom_kill and reports the
container was killed if the value is non-zero. This is erroneous in
some cases where containers create their children cgroups with
memory.oom.group=1 as such OOM kills will get counted against the
container cgroup's oom_kill counter despite not actually OOM killing
the entire container.
2) Reading memory.events.local will fail to identify OOM kills in leaf
cgroups (that don't set memory.oom.group) within the container
cgroup.
This patch adds a new oom_group_kill event when memory.oom.group
triggers to allow userspace to cleanly identify when an entire cgroup is
oom killed.
[schatzberg.dan@gmail.com: changes from Johannes and Chris] Link: https://lkml.kernel.org/r/20211213162511.2492267-1-schatzberg.dan@gmail.com Link: https://lkml.kernel.org/r/20211203162426.3375036-1-schatzberg.dan@gmail.com Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Chris Down <chris@chrisdown.name> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Alex Shi <alexs@kernel.org> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Donghai Qiao [Fri, 14 Jan 2022 22:05:32 +0000 (14:05 -0800)]
mm/page_counter: remove an incorrect call to propagate_protected_usage()
propagate_protected_usage() is called to propagate the usage change in
the page_counter structure. But there is a call to this function from
page_counter_try_charge() when there is actually no usage change. Hence
this call should be removed.
Link: https://lkml.kernel.org/r/20211118181125.3918222-1-dqiao@redhat.com Signed-off-by: Donghai Qiao <dqiao@redhat.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Muchun Song [Fri, 14 Jan 2022 22:05:29 +0000 (14:05 -0800)]
mm: memcontrol: make cgroup_memory_nokmem static
Commit 494c1dfe855e ("mm: memcg/slab: create a new set of kmalloc-cg-<n>
caches") makes cgroup_memory_nokmem global, however, it is unnecessary
because there is already a function mem_cgroup_kmem_disabled() which
exports it.
Just make it static and replace it with mem_cgroup_kmem_disabled() in
mm/slab_common.c.
Link: https://lkml.kernel.org/r/20211109065418.21693-1-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Chris Down <chris@chrisdown.name> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/frontswap.c: use non-atomic '__set_bit()' when possible
The 'a' and 'b' bitmaps are local to this function, so no concurrent
access can occur. So the non-atomic '__set_bit()' can be used to save a
few cycles.
Image there are 3 items in the local list (@list). In the first
traversal, A is not deleted from @list.
1) A->B->C
^
|
pos (leave)
In the second traversal, B is deleted from @list. Concurrently, A is
deleted from @list through shmem_evict_inode() since last reference
counter of inode is dropped by other thread. Then the @list is corrupted.
2) A->B->C
^ ^
| |
evict pos (drop)
We should make sure the inode is either on the global list or deleted from
any local list before iput().
Fixed by moving inodes back to global list before we put them.
[akpm@linux-foundation.org: coding style fixes]
Link: https://lkml.kernel.org/r/20211125064502.99983-1-ligang.bdlg@bytedance.com Fixes: 779750d20b93 ("shmem: split huge pages beyond i_size under memory pressure") Signed-off-by: Gang Li <ligang.bdlg@bytedance.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yang Shi [Fri, 14 Jan 2022 22:05:19 +0000 (14:05 -0800)]
mm: shmem: don't truncate page if memory failure happens
The current behavior of memory failure is to truncate the page cache
regardless of dirty or clean. If the page is dirty the later access
will get the obsolete data from disk without any notification to the
users. This may cause silent data loss. It is even worse for shmem
since shmem is in-memory filesystem, truncating page cache means
discarding data blocks. The later read would return all zero.
The right approach is to keep the corrupted page in page cache, any
later access would return error for syscalls or SIGBUS for page fault,
until the file is truncated, hole punched or removed. The regular
storage backed filesystems would be more complicated so this patch is
focused on shmem. This also unblock the support for soft offlining
shmem THP.
[akpm@linux-foundation.org: coding style fixes]
[arnd@arndb.de: fix uninitialized variable use in me_pagecache_clean()] Link: https://lkml.kernel.org/r/20211022064748.4173718-1-arnd@kernel.org
[Fix invalid pointer dereference in shmem_read_mapping_page_gfp() with a
slight different implementation from what Ajay Garg <ajaygargnsit@gmail.com>
and Muchun Song <songmuchun@bytedance.com> proposed and reworked the
error handling of shmem_write_begin() suggested by Linus] Link: https://lore.kernel.org/linux-mm/20211111084617.6746-1-ajaygargnsit@gmail.com/ Link: https://lkml.kernel.org/r/20211020210755.23964-6-shy828301@gmail.com Link: https://lkml.kernel.org/r/20211116193247.21102-1-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Ajay Garg <ajaygargnsit@gmail.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Andy Lavr <andy.lavr@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Li Xinhai [Fri, 14 Jan 2022 22:05:16 +0000 (14:05 -0800)]
mm/gup.c: stricter check on THP migration entry during follow_pmd_mask
When BUG_ON check for THP migration entry, the existing code only check
thp_migration_supported case, but not for !thp_migration_supported case.
If !thp_migration_supported() and !pmd_present(), the original code may
dead loop in theory. To make the BUG_ON check consistent, we need catch
both cases.
Move the BUG_ON check one step earlier, because if the bug happen we
should know it instead of depend on FOLL_MIGRATION been used by caller.
Because pmdval instead of *pmd is read by the is_pmd_migration_entry()
check, the existing code don't help to avoid useless locking within
pmd_migration_entry_wait(), so remove that check.
Link: https://lkml.kernel.org/r/20211217062559.737063-1-lixinhai.lxh@gmail.com Signed-off-by: Li Xinhai <lixinhai.lxh@gmail.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Zi Yan <ziy@nvidia.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 4dd845b5a3e5 ("mm/swapops: rework swap entry manipulation code")
had changed migtation entry related helpers. Just update
debug_vm_pgatble() synced documentation to reflect those changes.
dump_mapping() is a big chunk of dump_page(), and it'd be handy to be
able to call it when we don't have a struct page. Split it out and move
it to fs/inode.c. Take the opportunity to simplify some of the debug
messages a little.
Link: https://lkml.kernel.org/r/20211121121056.2870061-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrey Konovalov [Fri, 14 Jan 2022 22:05:01 +0000 (14:05 -0800)]
kasan: fix quarantine conflicting with init_on_free
KASAN's quarantine might save its metadata inside freed objects. As
this happens after the memory is zeroed by the slab allocator when
init_on_free is enabled, the memory coming out of quarantine is not
properly zeroed.
This causes lib/test_meminit.c tests to fail with Generic KASAN.
Zero the metadata when the object is removed from quarantine.
Marco Elver [Fri, 14 Jan 2022 22:04:54 +0000 (14:04 -0800)]
kasan: add ability to detect double-kmem_cache_destroy()
Because mm/slab_common.c is not instrumented with software KASAN modes,
it is not possible to detect use-after-free of the kmem_cache passed
into kmem_cache_destroy(). In particular, because of the s->refcount--
and subsequent early return if non-zero, KASAN would never be able to
see the double-free via kmem_cache_free(kmem_cache, s). To be able to
detect a double-kmem_cache_destroy(), check accessibility of the
kmem_cache, and in case of failure return early.
While KASAN_HW_TAGS is able to detect such bugs, by checking
accessibility and returning early we fail more gracefully and also avoid
corrupting reused objects (where tags mismatch).
A recent case of a double-kmem_cache_destroy() was detected by KFENCE:
https://lkml.kernel.org/r/0000000000003f654905c168b09d@google.com, which
was not detectable by software KASAN modes.
Link: https://lkml.kernel.org/r/20211119142219.1519617-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Marco Elver [Fri, 14 Jan 2022 22:04:51 +0000 (14:04 -0800)]
kasan: test: add globals left-out-of-bounds test
Add a test checking that KASAN generic can also detect out-of-bounds
accesses to the left of globals.
Unfortunately it seems that GCC doesn't catch this (tested GCC 10, 11).
The main difference between GCC's globals redzoning and Clang's is that
GCC relies on using increased alignment to producing padding, where
Clang's redzoning implementation actually adds real data after the
global and doesn't rely on alignment to produce padding. I believe this
is the main reason why GCC can't reliably catch globals out-of-bounds in
this case.
Given this is now a known issue, to avoid failing the whole test suite,
skip this test case with GCC.
Link: https://lkml.kernel.org/r/20211117130714.135656-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Reported-by: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kaiwan N Billimoria <kaiwan.billimoria@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joao Martins [Fri, 14 Jan 2022 22:04:47 +0000 (14:04 -0800)]
device-dax: compound devmap support
Use the newly added compound devmap facility which maps the assigned dax
ranges as compound pages at a page size of @align.
dax devices are created with a fixed @align (huge page size) which is
enforced through as well at mmap() of the device. Faults, consequently
happen too at the specified @align specified at the creation, and those
don't change throughout dax device lifetime. MCEs unmap a whole dax
huge page, as well as splits occurring at the configured page size.
Performance measured by gup_test improves considerably for
unpin_user_pages() and altmap with NVDIMMs:
$ gup_test -f /dev/dax1.0 -m 16384 -r 10 -S -a -n 512 -w
(pin_user_pages_fast 2M pages) put:~71 ms -> put:~22 ms
[altmap]
(pin_user_pages_fast 2M pages) get:~524ms put:~525 ms -> get: ~127ms put:~71ms
$ gup_test -f /dev/dax1.0 -m 129022 -r 10 -S -a -n 512 -w
(pin_user_pages_fast 2M pages) put:~513 ms -> put:~188 ms
[altmap with -m 127004]
(pin_user_pages_fast 2M pages) get:~4.1 secs put:~4.12 secs -> get:~1sec put:~563ms
.. as well as unpin_user_page_range_dirty_lock() being just as effective
as THP/hugetlb[0] pages.
Joao Martins [Fri, 14 Jan 2022 22:04:43 +0000 (14:04 -0800)]
device-dax: remove pfn from __dev_dax_{pte,pmd,pud}_fault()
After moving the page mapping to be set prior to pte insertion, the pfn
in dev_dax_huge_fault() no longer is necessary. Remove it, as well as
the @pfn argument passed to the internal fault handler helpers.
Joao Martins [Fri, 14 Jan 2022 22:04:40 +0000 (14:04 -0800)]
device-dax: set mapping prior to vmf_insert_pfn{,_pmd,pud}()
Normally, the @page mapping is set prior to inserting the page into a
page table entry. Make device-dax adhere to the same ordering, rather
than setting mapping after the PTE is inserted.
The address_space never changes and it is always associated with the
same inode and underlying pages. So, the page mapping is set once but
cleared when the struct pages are removed/freed (i.e. after
{devm_}memunmap_pages()).
Link: https://lkml.kernel.org/r/20211202204422.26777-10-joao.m.martins@oracle.com Suggested-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joao Martins [Fri, 14 Jan 2022 22:04:36 +0000 (14:04 -0800)]
device-dax: factor out page mapping initialization
Move initialization of page->mapping into a separate helper.
This is in preparation to move the mapping set to be prior to inserting
the page table entry and also for tidying up compound page handling into
one helper.
Link: https://lkml.kernel.org/r/20211202204422.26777-9-joao.m.martins@oracle.com Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joao Martins [Fri, 14 Jan 2022 22:04:33 +0000 (14:04 -0800)]
device-dax: ensure dev_dax->pgmap is valid for dynamic devices
Right now, only static dax regions have a valid @pgmap pointer in its
struct dev_dax. Dynamic dax case however, do not.
In preparation for device-dax compound devmap support, make sure that
dev_dax pgmap field is set after it has been allocated and initialized.
dynamic dax device have the @pgmap is allocated at probe() and it's
managed by devm (contrast to static dax region which a pgmap is provided
and dax core kfrees it). So in addition to ensure a valid @pgmap, clear
the pgmap when the dynamic dax device is released to avoid the same
pgmap ranges to be re-requested across multiple region device reconfigs.
Add a static_dev_dax() and use that helper in dev_dax_probe() to ensure
the initialization differences between dynamic and static regions are
more explicit. While at it, consolidate the ranges initialization when
we allocate the @pgmap for the dynamic dax region case. Also take the
opportunity to document the differences between static and dynamic da
regions.
Link: https://lkml.kernel.org/r/20211202204422.26777-8-joao.m.martins@oracle.com Suggested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joao Martins [Fri, 14 Jan 2022 22:04:26 +0000 (14:04 -0800)]
device-dax: use ALIGN() for determining pgoff
Rather than calculating @pgoff manually, switch to ALIGN() instead.
Link: https://lkml.kernel.org/r/20211202204422.26777-6-joao.m.martins@oracle.com Suggested-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joao Martins [Fri, 14 Jan 2022 22:04:22 +0000 (14:04 -0800)]
mm/memremap: add ZONE_DEVICE support for compound pages
Add a new @vmemmap_shift property for struct dev_pagemap which specifies
that a devmap is composed of a set of compound pages of order
@vmemmap_shift, instead of base pages. When a compound page devmap is
requested, all but the first page are initialised as tail pages instead
of order-0 pages.
For certain ZONE_DEVICE users like device-dax which have a fixed page
size, this creates an opportunity to optimize GUP and GUP-fast walkers,
treating it the same way as THP or hugetlb pages.
Additionally, commit 7118fc2906e2 ("hugetlb: address ref count racing in
prep_compound_gigantic_page") removed set_page_count() because the
setting of page ref count to zero was redundant. devmap pages don't
come from page allocator though and only head page refcount is used for
compound pages, hence initialize tail page count to zero.
Link: https://lkml.kernel.org/r/20211202204422.26777-5-joao.m.martins@oracle.com Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joao Martins [Fri, 14 Jan 2022 22:04:15 +0000 (14:04 -0800)]
mm/page_alloc: split prep_compound_page into head and tail subparts
Patch series "mm, device-dax: Introduce compound pages in devmap", v7.
This series converts device-dax to use compound pages, and moves away
from the 'struct page per basepage on PMD/PUD' that is done today.
Doing so
1) unlocks a few noticeable improvements on unpin_user_pages() and
makes device-dax+altmap case 4x times faster in pinning (numbers
below and in last patch)
2) as mentioned in various other threads it's one important step
towards cleaning up ZONE_DEVICE refcounting.
I've split the compound pages on devmap part from the rest based on
recent discussions on devmap pending and future work planned[5][6].
There is consensus that device-dax should be using compound pages to
represent its PMD/PUDs just like HugeTLB and THP, and that leads to less
specialization of the dax parts. I will pursue the rest of the work in
parallel once this part is merged, particular the GUP-{slow,fast}
improvements [7] and the tail struct page deduplication memory savings
part[8].
To summarize what the series does:
Patch 1: Prepare hwpoisoning to work with dax compound pages.
Patches 2-3: Split the current utility function of prep_compound_page()
into head and tail and use those two helpers where appropriate to take
advantage of caches being warm after __init_single_page(). This is used
when initializing zone device when we bring up device-dax namespaces.
Patches 4-10: Add devmap support for compound pages in device-dax.
memmap_init_zone_device() initialize its metadata as compound pages, and
it introduces a new devmap property known as vmemmap_shift which
outlines how the vmemmap is structured (defaults to base pages as done
today). The property describe the page order of the metadata
essentially. While at it do a few cleanups in device-dax in patches
5-9. Finally enable device-dax usage of devmap @vmemmap_shift to a
value based on its own @align property. @vmemmap_shift returns 0 by
default (which is today's case of base pages in devmap, like fsdax or
the others) and the usage of compound devmap is optional. Starting with
device-dax (*not* fsdax) we enable it by default. There are a few
pinning improvements particular on the unpinning case and altmap, as
well as unpin_user_page_range_dirty_lock() being just as effective as
THP/hugetlb[0] pages.
$ gup_test -f /dev/dax1.0 -m 16384 -r 10 -S -a -n 512 -w
(pin_user_pages_fast 2M pages) put:~71 ms -> put:~22 ms
[altmap]
(pin_user_pages_fast 2M pages) get:~524ms put:~525 ms -> get: ~127ms put:~71ms
$ gup_test -f /dev/dax1.0 -m 129022 -r 10 -S -a -n 512 -w
(pin_user_pages_fast 2M pages) put:~513 ms -> put:~188 ms
[altmap with -m 127004]
(pin_user_pages_fast 2M pages) get:~4.1 secs put:~4.12 secs -> get:~1sec put:~563ms
Tested on x86 with 1Tb+ of pmem (alongside registering it with RDMA with
and without altmap), alongside gup_test selftests with dynamic dax
regions and static dax regions. Coupled with ndctl unit tests for
dynamic dax devices that exercise all of this. Note, for dynamic dax
regions I had to revert commit 8aa83e6395 ("x86/setup: Call
early_reserve_memory() earlier"), it is a known issue that this commit
broke efi_fake_mem=.
This patch (of 11):
Split the utility function prep_compound_page() into head and tail
counterparts, and use them accordingly.
This is in preparation for sharing the storage for compound page
metadata.
Link: https://lkml.kernel.org/r/20211202204422.26777-1-joao.m.martins@oracle.com Link: https://lkml.kernel.org/r/20211202204422.26777-3-joao.m.martins@oracle.com Signed-off-by: Joao Martins <joao.m.martins@oracle.com> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Christoph Hellwig <hch@lst.de> Cc: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kefeng Wang [Fri, 14 Jan 2022 22:04:11 +0000 (14:04 -0800)]
mm: defer kmemleak object creation of module_alloc()
Yongqiang reports a kmemleak panic when module insmod/rmmod with KASAN
enabled(without KASAN_VMALLOC) on x86[1].
When the module area allocates memory, it's kmemleak_object is created
successfully, but the KASAN shadow memory of module allocation is not
ready, so when kmemleak scan the module's pointer, it will panic due to
no shadow memory with KASAN check.
Note, there is no problem if KASAN_VMALLOC enabled, the modules area
entire shadow memory is preallocated. Thus, the bug only exits on ARCH
which supports dynamic allocation of module area per module load, for
now, only x86/arm64/s390 are involved.
Add a VM_DEFER_KMEMLEAK flags, defer vmalloc'ed object register of
kmemleak in module_alloc() to fix this issue.
Calvin Zhang [Fri, 14 Jan 2022 22:04:08 +0000 (14:04 -0800)]
mm: kmemleak: alloc gray object for reserved region with direct map
Reserved regions with direct mapping may contain references to other
regions. CMA region with fixed location is reserved without creating
kmemleak_object for it.
So add them as gray kmemleak objects.
Link: https://lkml.kernel.org/r/20211123090641.3654006-1-calvinzhang.cool@gmail.com Signed-off-by: Calvin Zhang <calvinzhang.cool@gmail.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Frank Rowand <frowand.list@gmail.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A sequence like that may cause the warning as following:
1) Freeing unknown object:
In kfree(), we will get free unknown object warning in
kmemleak_free(). Because object(0xFx) in kmemleak rbtree and
pointer(0xFF) in kfree() have different tag.
2) Overlap existing:
When we allocate that object with the same hw-tag again, we will
find the overlap in the kmemleak rbtree and kmemleak thread will be
killed.
Muchun Song [Fri, 14 Jan 2022 22:04:01 +0000 (14:04 -0800)]
mm: slab: make slab iterator functions static
There is no external users of slab_start/next/stop(), so make them
static. And the memory.kmem.slabinfo is deprecated, which outputs
nothing now, so move memcg_slab_show() into mm/memcontrol.c and rename
it to mem_cgroup_slab_show to be consistent with other function names.
Link: https://lkml.kernel.org/r/20211109133359.32881-1-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Marco Elver [Fri, 14 Jan 2022 22:03:58 +0000 (14:03 -0800)]
mm/slab_common: use WARN() if cache still has objects on destroy
Calling kmem_cache_destroy() while the cache still has objects allocated
is a kernel bug, and will usually result in the entire cache being
leaked. While the message in kmem_cache_destroy() resembles a warning,
it is currently not implemented using a real WARN().
This is problematic for infrastructure testing the kernel, all of which
rely on the specific format of WARN()s to pick up on bugs.
Some 13 years ago this used to be a simple WARN_ON() in slub, but commit d629d8195793 ("slub: improve kmem_cache_destroy() error message")
changed it into an open-coded warning to avoid confusion with a bug in
slub itself.
Instead, turn the open-coded warning into a real WARN() with the message
preserved, so that test systems can actually identify these issues, and
we get all the other benefits of using a normal WARN(). The warning
message is extended with "when called from <caller-ip>" to make it even
clearer where the fault lies.
For most configurations this is only a cosmetic change, however, note
that WARN() here will now also respect panic_on_warn.
Link: https://lkml.kernel.org/r/20211102170733.648216-1-elver@google.com Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__user annotations are used by the checker (e.g sparse) to mark user
pointers. However here __user is applied to a struct directly, without a
pointer being directly involved.
Although the presence of __user does not cause sparse to emit a warning,
__user should be removed for consistency with other uses of offsetof().
Note: No functional changes intended.
Link: https://lkml.kernel.org/r/20211122101256.7875-1-amit.kachhap@arm.com Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Cc: Vincenzo Frascino <Vincenzo.Frascino@arm.com> Cc: Kevin Brodsky <Kevin.Brodsky@arm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Colin Ian King [Fri, 14 Jan 2022 22:03:51 +0000 (14:03 -0800)]
ocfs2: remove redundant assignment to variable free_space
The variable 'free_space' is being initialized with a value that is not
read, it is being re-assigned later in the two paths of an if statement.
The early initialization is redundant and can be removed.
Link: https://lkml.kernel.org/r/20220112230411.1090761-1-colin.i.king@gmail.com Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are currently two ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field.
Move the ocfs2 cluster sysfs code to use default_groups field which has
been the preferred way since aa30f47cf666 ("kobject: Add support for
default attribute groups to kobj_type") so that we can soon get rid of
the obsolete default_attrs field.
Link: https://lkml.kernel.org/r/20220106102028.3345634-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com> Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Colin Ian King [Fri, 14 Jan 2022 22:03:45 +0000 (14:03 -0800)]
ocfs2: remove redundant assignment to pointer root_bh
The variable 'root_bh' is being initialized with a value that is not
read, it is being re-assigned later on closer to its use. The early
initialization is redundant and can be removed.
Link: https://lkml.kernel.org/r/20211228013719.620923-1-colin.i.king@gmail.com Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are currently two ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field.
Move the ocfs2 code to use default_groups field which has been the
preferred way since aa30f47cf666 ("kobject: Add support for default
attribute groups to kobj_type") so that we can soon get rid of the
obsolete default_attrs field.
Link: https://lkml.kernel.org/r/20211228144517.391660-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Joseph Qi [Fri, 14 Jan 2022 22:03:38 +0000 (14:03 -0800)]
ocfs2: clearly handle ocfs2_grab_pages_for_write() return value
ocfs2_grab_pages_for_write() may return -EAGAIN if write context type is
mmap and it could not lock the target page. In this case, we exit with
no error and no target page. And then trigger the caller page_mkwrite()
to retry.
Since there are other caller types, e.g. buffer and direct io, make the
return value handling more clear.
Link: https://lkml.kernel.org/r/20211206065051.103353-1-joseph.qi@linux.alibaba.com Signed-off-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <gechangwei@live.cn> Cc: Gang He <ghe@suse.com> Cc: Jun Piao <piaojun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Zheng Liang [Fri, 14 Jan 2022 22:03:31 +0000 (14:03 -0800)]
squashfs: provide backing_dev_info in order to disable read-ahead
Commit c1f6925e1091 ("mm: put readahead pages in cache earlier") causes
the read performance of squashfs to deteriorate.Through testing, we find
that the performance will be back by closing the readahead of squashfs.
So we want to learn the way of ubifs, provides backing_dev_info and
disable read-ahead
We tested the following data by fio.
squashfs image blocksize=128K
test command:
Yang Li [Fri, 14 Jan 2022 22:03:28 +0000 (14:03 -0800)]
fs/ntfs/attrib.c: fix one kernel-doc comment
The comments for the file should not be in kernel-doc format:
/**
* attrib.c - NTFS attribute operations. Part of the Linux-NTFS
as it causes it to be incorrectly identified for function
ntfs_map_runlist_nolock(), causing some warnings found by running
scripts/kernel-doc.:
fs/ntfs/attrib.c:25: warning: Incorrect use of kernel-doc format: * ntfs_map_runlist_nolock - map (a part of) a runlist of an ntfs inode
fs/ntfs/attrib.c:71: warning: Function parameter or member 'ni' not described in 'ntfs_map_runlist_nolock'
fs/ntfs/attrib.c:71: warning: Function parameter or member 'vcn' not described in 'ntfs_map_runlist_nolock'
fs/ntfs/attrib.c:71: warning: Function parameter or member 'ctx' not described in 'ntfs_map_runlist_nolock'
fs/ntfs/attrib.c:71: warning: expecting prototype for attrib.c - NTFS attribute operations. Part of the Linux(). Prototype was for ntfs_map_runlist_nolock() instead
Link: https://lkml.kernel.org/r/20220106015145.67067-1-yang.lee@linux.alibaba.com Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Reported-by: Abaci Robot <abaci@linux.alibaba.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Cc: Anton Altaparmakov <anton@tuxera.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are currently two ways to create a set of sysfs files for a kobj_type,
through the default_attrs field, and the default_groups field.
Move the ia64 topology sysfs code to use default_groups field which has
been the preferred way since aa30f47cf666 ("kobject: Add support for
default attribute groups to kobj_type") so that we can soon get rid of
the obsolete default_attrs field.
Link: https://lkml.kernel.org/r/20220104154800.1287947-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
projects / mirror_ubuntu-kernels.git / log