Merge tag 'audit-pr-20180403' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit
Pull audit updates from Paul Moore:
"We didn't have anything to send for v4.16, but we're back with a
little more than usual for v4.17.
Eleven patches in total, most fall into the small fix category, but
there are three non-trivial changes worth calling out:
- the audit entry filter is being removed after deprecating it for
quite a while (years of no one really using it because it turns out
to be not very practical)
- created our own version of "__mutex_owner()" because the locking
folks were upset we were using theirs
- improved our handling of kernel command line parameters to make
them more forgiving
- we fixed auditing of symlink operations
Everything passes the audit-testsuite and as of a few minutes ago it
merges well with your tree"
* tag 'audit-pr-20180403' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
audit: add refused symlink to audit_names
audit: remove path param from link denied function
audit: link denied should not directly generate PATH record
audit: make ANOM_LINK obey audit_enabled and audit_dummy_context
audit: do not panic on invalid boot parameter
audit: track the owner of the command mutex ourselves
audit: return on memory error to avoid null pointer dereference
audit: bail before bug check if audit disabled
audit: deprecate the AUDIT_FILTER_ENTRY filter
audit: session ID should not set arch quick field pointer
audit: update bugtracker and source URIs
Merge tag 'pstore-v4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull pstore updates from Kees Cook:
"This cycle was almost entirely improvements to the pstore compression
options, noted below:
- Add lz4hc and 842 to pstore compression options (Geliang Tang)
- Refactor to use crypto compression API (Geliang Tang)
- Fix up Kconfig dependencies for compression (Arnd Bergmann)
- Allow for run-time compression selection
- Remove stack VLA usage"
* tag 'pstore-v4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
pstore: fix crypto dependencies
pstore: Use crypto compress API
pstore/ram: Do not use stack VLA for parity workspace
pstore: Select compression at runtime
pstore: Avoid size casts for 842 compression
pstore: Add lz4hc and 842 compression support
- the v9fs maintainers have been missing for a long time. I've taken
over v9fs patch slinging.
- most of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (116 commits)
mm,oom_reaper: check for MMF_OOM_SKIP before complaining
mm/ksm: fix interaction with THP
mm/memblock.c: cast constant ULLONG_MAX to phys_addr_t
headers: untangle kmemleak.h from mm.h
include/linux/mmdebug.h: make VM_WARN* non-rvals
mm/page_isolation.c: make start_isolate_page_range() fail if already isolated
mm: change return type to vm_fault_t
mm, oom: remove 3% bonus for CAP_SYS_ADMIN processes
mm, page_alloc: wakeup kcompactd even if kswapd cannot free more memory
kernel/fork.c: detect early free of a live mm
mm: make counting of list_lru_one::nr_items lockless
mm/swap_state.c: make bool enable_vma_readahead and swap_vma_readahead() static
block_invalidatepage(): only release page if the full page was invalidated
mm: kernel-doc: add missing parameter descriptions
mm/swap.c: remove @cold parameter description for release_pages()
mm/nommu: remove description of alloc_vm_area
zram: drop max_zpage_size and use zs_huge_class_size()
zsmalloc: introduce zs_huge_class_size()
mm: fix races between swapoff and flush dcache
fs/direct-io.c: minor cleanups in do_blockdev_direct_IO
...
Merge tag 'mtd/for-4.17' of git://git.infradead.org/linux-mtd
Pull MTD updates from Boris Brezillon:
"MTD Core:
- Remove support for asynchronous erase (not implemented by any of
the existing drivers anyway)
- Remove Cyrille from the list of SPI NOR and MTD maintainers
- Fix kernel doc headers
- Allow users to define the partitions parsers they want to test
through a DT property (compatible of the partitions subnode)
- Remove the bfin-async-flash driver (the only architecture using it
has been removed)
- Fix pagetest test
- Add extra checks in mtd_erase()
- Simplify the MTD partition creation logic and get rid of
mtd_add_device_partitions()
MTD Drivers:
- Add endianness information to the physmap DT binding
- Add Eon EN29LV400A IDs to JEDEC probe logic
- Use %*ph where appropriate
SPI NOR Drivers:
- Make fsl-quaspi assign different names to MTD devices connected to
the same QSPI controller
- Remove an unneeded driver.bus assigned in the fsl-qspi driver
NAND Core:
- Prepare arrival of the SPI NAND subsystem by implementing a generic
(interface-agnostic) layer to ease manipulation of NAND devices
- Move onenand code base to the drivers/mtd/nand/ dir
- Rework timing mode selection
- Provide a generic way for NAND chip drivers to flag a specific
GET/SET FEATURE operation as supported/unsupported
- Stop embedding ONFI/JEDEC param page in nand_chip
NAND Drivers:
- Rework/cleanup of the mxc driver
- Various cleanups in the vf610 driver
- Migrate the fsmc and vf610 to ->exec_op()
- Get rid of the pxa driver (replaced by marvell_nand)
- Support ->setup_data_interface() in the GPMI driver
- Fix probe error path in several drivers
- Remove support for unused hw_syndrome mode in sunxi_nand
- Various minor improvements"
* tag 'mtd/for-4.17' of git://git.infradead.org/linux-mtd: (89 commits)
dt-bindings: fsl-quadspi: Add the example of two SPI NOR
mtd: fsl-quadspi: Distinguish the mtd device names
mtd: nand: Fix some function description mismatches in core.c
mtd: fsl-quadspi: Remove unneeded driver.bus assignment
mtd: rawnand: marvell: Rename ->ecc_clk into ->core_clk
mtd: rawnand: s3c2410: enhance the probe function error path
mtd: rawnand: tango: fix probe function error path
mtd: rawnand: sh_flctl: fix the probe function error path
mtd: rawnand: omap2: fix the probe function error path
mtd: rawnand: mxc: fix probe function error path
mtd: rawnand: denali: fix probe function error path
mtd: rawnand: davinci: fix probe function error path
mtd: rawnand: cafe: fix probe function error path
mtd: rawnand: brcmnand: fix probe function error path
mtd: rawnand: sunxi: Stop supporting ECC_HW_SYNDROME mode
mtd: rawnand: marvell: Fix clock resource by adding a register clock
mtd: ftl: Use DIV_ROUND_UP()
mtd: Fix some function description mismatches in mtdcore.c
mtd: physmap_of: update struct map_info's swap as per map requirement
dt-bindings: mtd-physmap: Add endianness supports
...
Merge tag 'for-4.17/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- DM core passthrough ioctl fix to retain reference to DM table, and
that table's block devices, while issuing the ioctl to one of those
block devices.
- DM core passthrough ioctl fix to _not_ override the fmode_t used to
issue the ioctl. Overriding by using the fmode_t that the block
device was originally open with during DM table load is a liability.
- Add DM core support for secure erase forwarding and update the DM
linear and DM striped targets to support them.
- A DM core 4.16 stable fix to allow abnormal IO (e.g. discard, write
same, write zeroes) for targets that make use of the non-splitting IO
variant (as is done for multipath or thinp when layered directly on
NVMe).
- Allow DM targets to return a payload in response to a DM message that
they are sent. This is useful for DM targets that would like to
provide statistics data in response to DM messages.
- Update DM bufio to support non-power-of-2 block sizes. Numerous other
related changes prepare the DM bufio code for this support.
- Fix DM crypt to use a bounded amount of memory across the entire
system. This is to avoid OOM that can otherwise occur in response to
certain pathological IO workloads (e.g. discarding a large DM crypt
device).
- Add a 'check_at_most_once' feature to the DM verity target to allow
verity to be used on mobile devices that have very limited resources.
- Fix the DM integrity target to fail early if a keyed algorithm (e.g.
HMAC) is to be used but the key isn't set.
- Add non-power-of-2 support to the DM unstripe target.
- Eliminate the use of a Variable Length Array in the DM stripe target.
- Update the DM log-writes target to record metadata (REQ_META flag).
- DM raid fixes for its nosync status and some variable range issues.
* tag 'for-4.17/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (28 commits)
dm: remove fmode_t argument from .prepare_ioctl hook
dm: hold DM table for duration of ioctl rather than use blkdev_get
dm raid: fix parse_raid_params() variable range issue
dm verity: make verity_for_io_block static
dm verity: add 'check_at_most_once' option to only validate hashes once
dm bufio: don't embed a bio in the dm_buffer structure
dm bufio: support non-power-of-two block sizes
dm bufio: use slab cache for dm_buffer structure allocations
dm bufio: reorder fields in dm_buffer structure
dm bufio: relax alignment constraint on slab cache
dm bufio: remove code that merges slab caches
dm bufio: get rid of slab cache name allocations
dm bufio: move dm-bufio.h to include/linux/
dm bufio: delete outdated comment
dm: add support for secure erase forwarding
dm: backfill abnormal IO support to non-splitting IO submission
dm raid: fix nosync status
dm mpath: use DM_MAPIO_SUBMITTED instead of magic number 0 in process_queued_bios()
dm stripe: get rid of a Variable Length Array (VLA)
dm log writes: record metadata flag for better flags record
...
mm,oom_reaper: check for MMF_OOM_SKIP before complaining
I got "oom_reaper: unable to reap pid:" messages when the victim thread
was blocked inside free_pgtables() (which occurred after returning from
unmap_vmas() and setting MMF_OOM_SKIP). We don't need to complain when
exit_mmap() already set MMF_OOM_SKIP.
This patch fixes a corner case for KSM. When two pages belong or
belonged to the same transparent hugepage, and they should be merged,
KSM fails to split the page, and therefore no merging happens.
This bug can be reproduced by:
* making sure ksm is running (in case disabling ksmtuned)
* enabling transparent hugepages
* allocating a THP-aligned 1-THP-sized buffer
e.g. on amd64: posix_memalign(&p, 1<<21, 1<<21)
* filling it with the same values
e.g. memset(p, 42, 1<<21)
* performing madvise to make it mergeable
e.g. madvise(p, 1<<21, MADV_MERGEABLE)
* waiting for KSM to perform a few scans
The expected outcome is that the all the pages get merged (1 shared and
the rest sharing); the actual outcome is that no pages get merged (1
unshared and the rest volatile)
The reason of this behaviour is that we increase the reference count
once for both pages we want to merge, but if they belong to the same
hugepage (or compound page), the reference counter used in both cases is
the one of the head of the compound page. This means that
split_huge_page will find a value of the reference counter too high and
will fail.
This patch solves this problem by testing if the two pages to merge
belong to the same hugepage when attempting to merge them. If so, the
hugepage is split safely. This means that the hugepage is not split if
not necessary.
Link: http://lkml.kernel.org/r/1521548069-24758-1-git-send-email-imbrenda@linux.vnet.ibm.com Signed-off-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Co-authored-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Stefan Agner [Thu, 5 Apr 2018 23:25:38 +0000 (16:25 -0700)]
mm/memblock.c: cast constant ULLONG_MAX to phys_addr_t
This fixes a warning shown when phys_addr_t is 32-bit int when compiling
with clang:
mm/memblock.c:927:15: warning: implicit conversion from 'unsigned long long'
to 'phys_addr_t' (aka 'unsigned int') changes value from 18446744073709551615 to 4294967295 [-Wconstant-conversion]
r->base : ULLONG_MAX;
^~~~~~~~~~
./include/linux/kernel.h:30:21: note: expanded from macro 'ULLONG_MAX'
#define ULLONG_MAX (~0ULL)
^~~~~
Link: http://lkml.kernel.org/r/20180319005645.29051-1-stefan@agner.ch Signed-off-by: Stefan Agner <stefan@agner.ch> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Pavel Tatashin <pasha.tatashin@oracle.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Thu, 5 Apr 2018 23:25:34 +0000 (16:25 -0700)]
headers: untangle kmemleak.h from mm.h
Currently <linux/slab.h> #includes <linux/kmemleak.h> for no obvious
reason. It looks like it's only a convenience, so remove kmemleak.h
from slab.h and add <linux/kmemleak.h> to any users of kmemleak_* that
don't already #include it. Also remove <linux/kmemleak.h> from source
files that do not use it.
This is tested on i386 allmodconfig and x86_64 allmodconfig. It would
be good to run it through the 0day bot for other $ARCHes. I have
neither the horsepower nor the storage space for the other $ARCHes.
Update: This patch has been extensively build-tested by both the 0day
bot & kisskb/ozlabs build farms. Both of them reported 2 build failures
for which patches are included here (in v2).
[ slab.h is the second most used header file after module.h; kernel.h is
right there with slab.h. There could be some minor error in the
counting due to some #includes having comments after them and I didn't
combine all of those. ]
[akpm@linux-foundation.org: security/keys/big_key.c needs vmalloc.h, per sfr] Link: http://lkml.kernel.org/r/e4309f98-3749-93e1-4bb7-d9501a39d015@infradead.org Link: http://kisskb.ellerman.id.au/kisskb/head/13396/ Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Reported-by: Michael Ellerman <mpe@ellerman.id.au> [2 build failures] Reported-by: Fengguang Wu <fengguang.wu@intel.com> [2 build failures] Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Wei Yongjun <weiyongjun1@huawei.com> Cc: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: John Johansen <john.johansen@canonical.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 5 Apr 2018 23:25:30 +0000 (16:25 -0700)]
include/linux/mmdebug.h: make VM_WARN* non-rvals
At present the construct
if (VM_WARN(...))
will compile OK with CONFIG_DEBUG_VM=y and will fail with
CONFIG_DEBUG_VM=n. The reason is that VM_{WARN,BUG}* have always been
special wrt. {WARN/BUG}* and never generate any code when DEBUG_VM is
disabled. So we cannot really use it in conditionals.
We considered changing things so that this construct works in both cases
but that might cause unwanted code generation with CONFIG_DEBUG_VM=n.
It is safer and simpler to make the build fail in both cases.
[akpm@linux-foundation.org: changelog] Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Kravetz [Thu, 5 Apr 2018 23:25:26 +0000 (16:25 -0700)]
mm/page_isolation.c: make start_isolate_page_range() fail if already isolated
start_isolate_page_range() is used to set the migrate type of a set of
pageblocks to MIGRATE_ISOLATE while attempting to start a migration
operation. It assumes that only one thread is calling it for the
specified range. This routine is used by CMA, memory hotplug and
gigantic huge pages. Each of these users synchronize access to the
range within their subsystem. However, two subsystems (CMA and gigantic
huge pages for example) could attempt operations on the same range. If
this happens, one thread may 'undo' the work another thread is doing.
This can result in pageblocks being incorrectly left marked as
MIGRATE_ISOLATE and therefore not available for page allocation.
What is ideally needed is a way to synchronize access to a set of
pageblocks that are undergoing isolation and migration. The only thing
we know about these pageblocks is that they are all in the same zone. A
per-node mutex is too coarse as we want to allow multiple operations on
different ranges within the same zone concurrently. Instead, we will
use the migration type of the pageblocks themselves as a form of
synchronization.
start_isolate_page_range sets the migration type on a set of page-
blocks going in order from the one associated with the smallest pfn to
the largest pfn. The zone lock is acquired to check and set the
migration type. When going through the list of pageblocks check if
MIGRATE_ISOLATE is already set. If so, this indicates another thread is
working on this pageblock. We know exactly which pageblocks we set, so
clean up by undo those and return -EBUSY.
This allows start_isolate_page_range to serve as a synchronization
mechanism and will allow for more general use of callers making use of
these interfaces. Update comments in alloc_contig_range to reflect this
new functionality.
Each CPU holds the associated zone lock to modify or examine the
migration type of a pageblock. And, it will only examine/update a
single pageblock per lock acquire/release cycle.
Link: http://lkml.kernel.org/r/20180309224731.16978-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The plan for these patches is to introduce the typedef, initially just
as documentation ("These functions should return a VM_FAULT_ status").
We'll trickle the patches to individual drivers/filesystems in through
the maintainers, as far as possible. Then we'll change the typedef to
an unsigned int and break the compilation of any unconverted
drivers/filesystems.
vmf_insert_page(), vmf_insert_mixed() and vmf_insert_pfn() are three
newly added functions. The various drivers/filesystems where return
value of fault(), huge_fault(), page_mkwrite() and pfn_mkwrite() get
converted, will need them. These functions will return correct
VM_FAULT_ code based on err value.
We've had bugs before where drivers returned -EFOO. And we have this
silly inefficiency where vm_insert_xxx() return an errno which (afaict)
every driver then converts into a VM_FAULT code. In many cases drivers
failed to return correct VM_FAULT code value despite of vm_insert_xxx()
fails. We have indentified and clean up all those existing bugs and
silly inefficiencies in driver/filesystems by adding these three new
inline wrappers. As mentioned above, we will trickle those patches to
individual drivers/filesystems in through maintainers after these three
wrapper functions are merged.
Eventually we can convert vm_insert_xxx() into vmf_insert_xxx() and
remove these inline wrappers, but these are a good intermediate step.
Link: http://lkml.kernel.org/r/20180310162351.GA7422@jordon-HP-15-Notebook-PC Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Rientjes [Thu, 5 Apr 2018 23:25:19 +0000 (16:25 -0700)]
mm, oom: remove 3% bonus for CAP_SYS_ADMIN processes
Since the 2.6 kernel, the oom killer has slightly biased away from
CAP_SYS_ADMIN processes by discounting some of its memory usage in
comparison to other processes.
This has always been implicit and nothing exactly relies on the
behavior.
Gaurav notices that __task_cred() can dereference a potentially freed
pointer if the task under consideration is exiting because a reference
to the task_struct is not held.
Remove the CAP_SYS_ADMIN bias so that all processes are treated equally.
If any CAP_SYS_ADMIN process would like to be biased against, it is
always allowed to adjust /proc/pid/oom_score_adj.
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803071548510.6996@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Reported-by: Gaurav Kohli <gkohli@codeaurora.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Rientjes [Thu, 5 Apr 2018 23:25:16 +0000 (16:25 -0700)]
mm, page_alloc: wakeup kcompactd even if kswapd cannot free more memory
Kswapd will not wakeup if per-zone watermarks are not failing or if too
many previous attempts at background reclaim have failed.
This can be true if there is a lot of free memory available. For high-
order allocations, kswapd is responsible for waking up kcompactd for
background compaction. If the zone is not below its watermarks or
reclaim has recently failed (lots of free memory, nothing left to
reclaim), kcompactd does not get woken up.
When __GFP_DIRECT_RECLAIM is not allowed, allow kcompactd to still be
woken up even if kswapd will not reclaim. This allows high-order
allocations, such as thp, to still trigger background compaction even
when the zone has an abundance of free memory.
Mark Rutland [Thu, 5 Apr 2018 23:25:12 +0000 (16:25 -0700)]
kernel/fork.c: detect early free of a live mm
KASAN splats indicate that in some cases we free a live mm, then
continue to access it, with potentially disastrous results. This is
likely due to a mismatched mmdrop() somewhere in the kernel, but so far
the culprit remains elusive.
Let's have __mmdrop() verify that the mm isn't live for the current
task, similar to the existing check for init_mm. This way, we can catch
this class of issue earlier, and without requiring KASAN.
Currently, idle_task_exit() leaves active_mm stale after it switches to
init_mm. This isn't harmful, but will trigger the new assertions, so we
must adjust idle_task_exit() to update active_mm.
Link: http://lkml.kernel.org/r/20180312140103.19235-1-mark.rutland@arm.com Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: make counting of list_lru_one::nr_items lockless
During the reclaiming slab of a memcg, shrink_slab iterates over all
registered shrinkers in the system, and tries to count and consume
objects related to the cgroup. In case of memory pressure, this behaves
bad: I observe high system time and time spent in list_lru_count_one()
for many processes on RHEL7 kernel.
This patch makes list_lru_node::memcg_lrus rcu protected, that allows to
skip taking spinlock in list_lru_count_one().
Shakeel Butt with the patch observes significant perf graph change. He
says:
========================================================================
Setup: running a fork-bomb in a memcg of 200MiB on a 8GiB and 4 vcpu
VM and recording the trace with 'perf record -g -a'.
Colin Ian King [Thu, 5 Apr 2018 23:25:05 +0000 (16:25 -0700)]
mm/swap_state.c: make bool enable_vma_readahead and swap_vma_readahead() static
The bool enable_vma_readahead and swap_vma_readahead() are local to the
source and do not need to be in global scope, so make them static.
Cleans up sparse warnings:
mm/swap_state.c:41:6: warning: symbol 'enable_vma_readahead' was not declared. Should it be static?
mm/swap_state.c:742:13: warning: symbol 'swap_vma_readahead' was not declared. Should it be static?
Link: http://lkml.kernel.org/r/20180223164852.5159-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: "Huang, Ying" <ying.huang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jeff Moyer [Thu, 5 Apr 2018 23:25:01 +0000 (16:25 -0700)]
block_invalidatepage(): only release page if the full page was invalidated
Prior to commit d47992f86b30 ("mm: change invalidatepage prototype to
accept length"), an offset of 0 meant that the full page was being
invalidated. After that commit, we need to instead check the length.
Jan said:
:
: The only possible issue is that try_to_release_page() was called more
: often than necessary. Otherwise the issue is harmless but still it's good
: to have this fixed.
Link: http://lkml.kernel.org/r/x49fu5rtnzs.fsf@segfault.boston.devel.redhat.com Fixes: d47992f86b307 ("mm: change invalidatepage prototype to accept length") Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Lukas Czerner <lczerner@redhat.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mike Rapoport [Thu, 5 Apr 2018 23:24:50 +0000 (16:24 -0700)]
mm/nommu: remove description of alloc_vm_area
The alloc_mm_area in nommu is a stub, but its description states it
allocates kernel address space. Remove the description to make the code
and the documentation agree.
zram: drop max_zpage_size and use zs_huge_class_size()
Remove ZRAM's enforced "huge object" value and use zsmalloc huge-class
watermark instead, which makes more sense.
TEST
- I used a 1G zram device, LZO compression back-end, original
data set size was 444MB. Looking at zsmalloc classes stats the
test ended up to be pretty fair.
BASE ZRAM/ZSMALLOC
=====================
zram mm_stat
As we can see, we reduced the number of objects stored in class-4096,
because a huge number of objects which we previously forcibly stored in
class-4096 now stored in non-huge class-3264. This results in lower
memory consumption:
- zsmalloc now uses 47424 physical pages, which is less than 48787 pages
zsmalloc used before.
- objects that we store in class-3264 share zspages. That's why overall
the number of pages that both class-4096 and class-3264 consumed went
down from 10924 to 9564.
Patch series "zsmalloc/zram: drop zram's max_zpage_size", v3.
ZRAM's max_zpage_size is a bad thing. It forces zsmalloc to store
normal objects as huge ones, which results in bigger zsmalloc memory
usage. Drop it and use actual zsmalloc huge-class value when decide if
the object is huge or not.
This patch (of 2):
Not every object can be share its zspage with other objects, e.g. when
the object is as big as zspage or nearly as big a zspage. For such
objects zsmalloc has a so called huge class - every object which belongs
to huge class consumes the entire zspage (which consists of a physical
page). On x86_64, PAGE_SHIFT 12 box, the first non-huge class size is
3264, so starting down from size 3264, objects can share page(-s) and
thus minimize memory wastage.
ZRAM, however, has its own statically defined watermark for huge
objects, namely "3 * PAGE_SIZE / 4 = 3072", and forcibly stores every
object larger than this watermark (3072) as a PAGE_SIZE object, in other
words, to a huge class, while zsmalloc can keep some of those objects in
non-huge classes. This results in increased memory consumption.
zsmalloc knows better if the object is huge or not. Introduce
zs_huge_class_size() function which tells if the given object can be
stored in one of non-huge classes or not. This will let us to drop
ZRAM's huge object watermark and fully rely on zsmalloc when we decide
if the object is huge.
Thanks to commit 4b3ef9daa4fc ("mm/swap: split swap cache into 64MB
trunks"), after swapoff the address_space associated with the swap
device will be freed. So page_mapping() users which may touch the
address_space need some kind of mechanism to prevent the address_space
from being freed during accessing.
The dcache flushing functions (flush_dcache_page(), etc) in architecture
specific code may access the address_space of swap device for anonymous
pages in swap cache via page_mapping() function. But in some cases
there are no mechanisms to prevent the swap device from being swapoff,
for example,
The address space may be accessed after being freed.
But from cachetlb.txt and Russell King, flush_dcache_page() only care
about file cache pages, for anonymous pages, flush_anon_page() should be
used. The implementation of flush_dcache_page() in all architectures
follows this too. They will check whether page_mapping() is NULL and
whether mapping_mapped() is true to determine whether to flush the
dcache immediately. And they will use interval tree (mapping->i_mmap)
to find all user space mappings. While mapping_mapped() and
mapping->i_mmap isn't used by anonymous pages in swap cache at all.
So, to fix the race between swapoff and flush dcache, __page_mapping()
is add to return the address_space for file cache pages and NULL
otherwise. All page_mapping() invoking in flush dcache functions are
replaced with page_mapping_file().
[akpm@linux-foundation.org: simplify page_mapping_file(), per Mike] Link: http://lkml.kernel.org/r/20180305083634.15174-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nikolay Borisov [Thu, 5 Apr 2018 23:24:36 +0000 (16:24 -0700)]
fs/direct-io.c: minor cleanups in do_blockdev_direct_IO
We already get the block counts and calculate the end block at the
beginning of the function. Let's use the local variables for
consistency and readability. No functional changes
[akpm@linux-foundation.org: constify the locals to prevent future slipups] Link: http://lkml.kernel.org/r/1519638870-17756-1-git-send-email-nborisov@suse.com Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/mm.h: provide consistent declaration for num_poisoned_pages
clang reports the following compile warning.
In file included from mm/vmscan.c:56:
./include/linux/swapops.h:327:22: warning:
section attribute is specified on redeclared variable [-Wsection]
extern atomic_long_t num_poisoned_pages __read_mostly;
^
./include/linux/mm.h:2585:22: note: previous declaration is here
extern atomic_long_t num_poisoned_pages;
^
Let's use __read_mostly everywhere.
Link: http://lkml.kernel.org/r/1519686565-8224-1-git-send-email-linux@roeck-us.net Signed-off-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Williams [Thu, 5 Apr 2018 23:24:28 +0000 (16:24 -0700)]
device-dax: implement ->pagesize() for smaps to report MMUPageSize
Given that device-dax is making similar page mapping size guarantees as
hugetlbfs, emit the size in smaps and any other kernel path that
requests the mapping size of a vma.
Link: http://lkml.kernel.org/r/151996255287.27922.18397777516059080245.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Williams [Thu, 5 Apr 2018 23:24:25 +0000 (16:24 -0700)]
mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct
When device-dax is operating in huge-page mode we want it to behave like
hugetlbfs and report the MMU page mapping size that is being enforced by
the vma.
Similar to commit 31383c6865a5 "mm, hugetlbfs: introduce ->split() to
vm_operations_struct" it would be messy to teach vma_mmu_pagesize()
about device-dax page mapping sizes in the same (hstate) way that
hugetlbfs communicates this attribute. Instead, these patches introduce
a new ->pagesize() vm operation.
Link: http://lkml.kernel.org/r/151996254734.27922.15813097401404359642.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reported-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dan Williams [Thu, 5 Apr 2018 23:24:21 +0000 (16:24 -0700)]
mm, powerpc: use vma_kernel_pagesize() in vma_mmu_pagesize()
Patch series "mm, smaps: MMUPageSize for device-dax", v3.
Similar to commit 31383c6865a5 ("mm, hugetlbfs: introduce ->split() to
vm_operations_struct") here is another occasion where we want
special-case hugetlbfs/hstate enabling to also apply to device-dax.
This prompts the question what other hstate conversions we might do
beyond ->split() and ->pagesize(), but this appears to be the last of
the usages of hstate_vma() in generic/non-hugetlbfs specific code paths.
This patch (of 3):
The current powerpc definition of vma_mmu_pagesize() open codes looking
up the page size via hstate. It is identical to the generic
vma_kernel_pagesize() implementation.
Now, vma_kernel_pagesize() is growing support for determining the page
size of Device-DAX vmas in addition to the existing Hugetlbfs page size
determination.
Ideally, if the powerpc vma_mmu_pagesize() used vma_kernel_pagesize() it
would automatically benefit from any new vma-type support that is added
to vma_kernel_pagesize(). However, the powerpc vma_mmu_pagesize() is
prevented from calling vma_kernel_pagesize() due to a circular header
dependency that requires vma_mmu_pagesize() to be defined before
including <linux/hugetlb.h>.
Break this circular dependency by defining the default vma_mmu_pagesize()
as a __weak symbol to be overridden by the powerpc version.
Link: http://lkml.kernel.org/r/151996254179.27922.2213728278535578744.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Jane Chu <jane.chu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Aaron Lu [Thu, 5 Apr 2018 23:24:14 +0000 (16:24 -0700)]
mm/free_pcppages_bulk: prefetch buddy while not holding lock
When a page is freed back to the global pool, its buddy will be checked
to see if it's possible to do a merge. This requires accessing buddy's
page structure and that access could take a long time if it's cache
cold.
This patch adds a prefetch to the to-be-freed page's buddy outside of
zone->lock in hope of accessing buddy's page structure later under
zone->lock will be faster. Since we *always* do buddy merging and check
an order-0 page's buddy to try to merge it when it goes into the main
allocator, the cacheline will always come in, i.e. the prefetched data
will never be unused.
Normally, the number of prefetch will be pcp->batch(default=31 and has
an upper limit of (PAGE_SHIFT * 8)=96 on x86_64) but in the case of
pcp's pages get all drained, it will be pcp->count which has an upper
limit of pcp->high. pcp->high, although has a default value of 186
(pcp->batch=31 * 6), can be changed by user through
/proc/sys/vm/percpu_pagelist_fraction and there is no software upper
limit so could be large, like several thousand. For this reason, only
the first pcp->batch number of page's buddy structure is prefetched to
avoid excessive prefetching.
In the meantime, there are two concerns:
1. the prefetch could potentially evict existing cachelines, especially
for L1D cache since it is not huge
2. there is some additional instruction overhead, namely calculating
buddy pfn twice
For 1, it's hard to say, this microbenchmark though shows good result
but the actual benefit of this patch will be workload/CPU dependant;
For 2, since the calculation is a XOR on two local variables, it's
expected in many cases that cycles spent will be offset by reduced
memory latency later. This is especially true for NUMA machines where
multiple CPUs are contending on zone->lock and the most time consuming
part under zone->lock is the wait of 'struct page' cacheline of the
to-be-freed pages and their buddies.
Aaron Lu [Thu, 5 Apr 2018 23:24:10 +0000 (16:24 -0700)]
mm/free_pcppages_bulk: do not hold lock when picking pages to free
When freeing a batch of pages from Per-CPU-Pages(PCP) back to buddy, the
zone->lock is held and then pages are chosen from PCP's migratetype
list. While there is actually no need to do this 'choose part' under
lock since it's PCP pages, the only CPU that can touch them is us and
irq is also disabled.
Moving this part outside could reduce lock held time and improve
performance. Test with will-it-scale/page_fault1 full load:
Aaron Lu [Thu, 5 Apr 2018 23:24:06 +0000 (16:24 -0700)]
mm/free_pcppages_bulk: update pcp->count inside
Matthew Wilcox found that all callers of free_pcppages_bulk() currently
update pcp->count immediately after so it's natural to do it inside
free_pcppages_bulk().
No functionality or performance change is expected from this patch.
Link: http://lkml.kernel.org/r/20180301062845.26038-2-aaron.lu@intel.com Signed-off-by: Aaron Lu <aaron.lu@intel.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Huang Ying <ying.huang@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Kemi Wang <kemi.wang@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Rientjes [Thu, 5 Apr 2018 23:24:02 +0000 (16:24 -0700)]
mm, compaction: drain pcps for zone when kcompactd fails
It's possible for free pages to become stranded on per-cpu pagesets
(pcps) that, if drained, could be merged with buddy pages on the zone's
free area to form large order pages, including up to MAX_ORDER.
Consider a verbose example using the tools/vm/page-types tool at the
beginning of a ZONE_NORMAL ('B' indicates a buddy page and 'S' indicates
a slab page). Pages on pcps do not have any page flags set.
The compaction migration scanner is attempting to defragment this memory
since it is at the beginning of the zone. It has done so quite well,
all movable pages have been migrated. From pfn [0x109955, 0x109fab),
there are only buddy pages and pages without flags set.
These pages may be stranded on pcps that could otherwise allow this
memory to be coalesced if freed back to the zone free area. It is
possible that some of these pages may not be on pcps and that something
has called alloc_pages() and used the memory directly, but we rely on
the absence of __GFP_MOVABLE in these cases to allocate from
MIGATE_UNMOVABLE pageblocks to try to keep these MIGRATE_MOVABLE
pageblocks as free as possible.
These buddy and pcp pages, spanning 1,621 pages, could be coalesced and
allow for three transparent hugepages to be dynamically allocated.
Running the numbers for all such spans on the system, it was found that
there were over 400 such spans of only buddy pages and pages without
flags set at the time this /proc/kpageflags sample was collected.
Without this support, there were _no_ order-9 or order-10 pages free.
When kcompactd fails to defragment memory such that a cc.order page can
be allocated, drain all pcps for the zone back to the buddy allocator so
this stranding cannot occur. Compaction for that order will
subsequently be deferred, which acts as a ratelimit on this drain.
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803010340100.88270@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> 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>
mm: make should_failslab always available for fault injection
should_failslab() is a convenient function to hook into for directed
error injection into kmalloc(). However, it is only available if a
config flag is set.
The following BCC script, for example, fails kmalloc() calls after a
btrfs umount:
int kprobe__should_failslab(struct pt_regs *ctx) {
u64 key = 1;
u64 *res;
res = flag.lookup(&key);
if (res != 0) {
bpf_override_return(ctx, -ENOMEM);
}
return 0;
}
"""
b = BPF(text=prog)
while 1:
b.kprobe_poll()
This patch refactors the should_failslab implementation so that the
function is always available for error injection, independent of flags.
This change would be similar in nature to commit f5490d3ec921 ("block:
Add should_fail_bio() for bpf error injection").
Link: http://lkml.kernel.org/r/20180222020320.6944-1-hmclauchlan@fb.com Signed-off-by: Howard McLauchlan <hmclauchlan@fb.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Akinobu Mita <akinobu.mita@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: Josef Bacik <jbacik@fb.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Alexei Starovoitov <ast@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Minchan Kim [Thu, 5 Apr 2018 23:23:42 +0000 (16:23 -0700)]
mm: swap: unify cluster-based and vma-based swap readahead
This patch makes do_swap_page() not need to be aware of two different
swap readahead algorithms. Just unify cluster-based and vma-based
readahead function call.
Minchan Kim [Thu, 5 Apr 2018 23:23:39 +0000 (16:23 -0700)]
mm: swap: clean up swap readahead
When I see recent change of swap readahead, I am very unhappy about
current code structure which diverges two swap readahead algorithm in
do_swap_page. This patch is to clean it up.
Main motivation is that fault handler doesn't need to be aware of
readahead algorithms but just should call swapin_readahead.
As first step, this patch cleans up a little bit but not perfect (I just
separate for review easier) so next patch will make the goal complete.
mm,vmscan: don't pretend forward progress upon shrinker_rwsem contention
Since we no longer use return value of shrink_slab() for normal reclaim,
the comment is no longer true. If some do_shrink_slab() call takes
unexpectedly long (root cause of stall is currently unknown) when
register_shrinker()/unregister_shrinker() is pending, trying to drop
caches via /proc/sys/vm/drop_caches could become infinite cond_resched()
loop if many mem_cgroup are defined. For safety, let's not pretend
forward progress.
Link: http://lkml.kernel.org/r/201802202229.GGF26507.LVFtMSOOHFJOQF@I-love.SAKURA.ne.jp Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Chinner <dchinner@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently if z3fold couldn't find an unbuddied page it would first try
to pull a page off the stale list. The problem with this approach is
that we can't 100% guarantee that the page is not processed by the
workqueue thread at the same time unless we run cancel_work_sync() on
it, which we can't do if we're in an atomic context. So let's just
limit stale list usage to non-atomic contexts only.
Link: http://lkml.kernel.org/r/47ab51e7-e9c1-d30e-ab17-f734dbc3abce@gmail.com Signed-off-by: Vitaly Vul <vitaly.vul@sony.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: <Oleksiy.Avramchenko@sony.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/huge_memory.c: reorder operations in __split_huge_page_tail()
THP split makes non-atomic change of tail page flags. This is almost ok
because tail pages are locked and isolated but this breaks recent
changes in page locking: non-atomic operation could clear bit
PG_waiters.
As a result concurrent sequence get_page_unless_zero() -> lock_page()
might block forever. Especially if this page was truncated later.
Fix is trivial: clone flags before unfreezing page reference counter.
This race exists since commit 62906027091f ("mm: add PageWaiters
indicating tasks are waiting for a page bit") while unsave unfreeze
itself was added in commit 8df651c7059e ("thp: cleanup
split_huge_page()").
clear_compound_head() also must be called before unfreezing page
reference because after successful get_page_unless_zero() might follow
put_page() which needs correct compound_head().
And replace page_ref_inc()/page_ref_add() with page_ref_unfreeze() which
is made especially for that and has semantic of smp_store_release().
Link: http://lkml.kernel.org/r/151844393341.210639.13162088407980624477.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: fix races between address_space dereference and free in page_evicatable
When page_mapping() is called and the mapping is dereferenced in
page_evicatable() through shrink_active_list(), it is possible for the
inode to be truncated and the embedded address space to be freed at the
same time. This may lead to the following race.
CPU1 CPU2
truncate(inode) shrink_active_list()
... page_evictable(page)
truncate_inode_page(mapping, page);
delete_from_page_cache(page)
spin_lock_irqsave(&mapping->tree_lock, flags);
__delete_from_page_cache(page, NULL)
page_cache_tree_delete(..)
... mapping = page_mapping(page);
page->mapping = NULL;
...
spin_unlock_irqrestore(&mapping->tree_lock, flags);
page_cache_free_page(mapping, page)
put_page(page)
if (put_page_testzero(page)) -> false
- inode now has no pages and can be freed including embedded address_space
mapping_unevictable(mapping)
test_bit(AS_UNEVICTABLE, &mapping->flags);
- we've dereferenced mapping which is potentially already free.
Similar race exists between swap cache freeing and page_evicatable()
too.
The address_space in inode and swap cache will be freed after a RCU
grace period. So the races are fixed via enclosing the page_mapping()
and address_space usage in rcu_read_lock/unlock(). Some comments are
added in code to make it clear what is protected by the RCU read lock.
Link: http://lkml.kernel.org/r/20180212081227.1940-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@kernel.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Rientjes [Thu, 5 Apr 2018 23:23:09 +0000 (16:23 -0700)]
mm, page_alloc: extend kernelcore and movablecore for percent
Both kernelcore= and movablecore= can be used to define the amount of
ZONE_NORMAL and ZONE_MOVABLE on a system, respectively. This requires
the system memory capacity to be known when specifying the command line,
however.
This introduces the ability to define both kernelcore= and movablecore=
as a percentage of total system memory. This is convenient for systems
software that wants to define the amount of ZONE_MOVABLE, for example,
as a proportion of a system's memory rather than a hardcoded byte value.
To define the percentage, the final character of the parameter should be
a '%'.
mhocko: "why is anyone using these options nowadays?"
rientjes:
:
: Fragmentation of non-__GFP_MOVABLE pages due to low on memory
: situations can pollute most pageblocks on the system, as much as 1GB of
: slab being fragmented over 128GB of memory, for example. When the
: amount of kernel memory is well bounded for certain systems, it is
: better to aggressively reclaim from existing MIGRATE_UNMOVABLE
: pageblocks rather than eagerly fallback to others.
:
: We have additional patches that help with this fragmentation if you're
: interested, specifically kcompactd compaction of MIGRATE_UNMOVABLE
: pageblocks triggered by fallback of non-__GFP_MOVABLE allocations and
: draining of pcp lists back to the zone free area to prevent stranding.
mm: hwpoison: disable memory error handling on 1GB hugepage
Recently the following BUG was reported:
Injecting memory failure for pfn 0x3c0000 at process virtual address 0x7fe300000000
Memory failure: 0x3c0000: recovery action for huge page: Recovered
BUG: unable to handle kernel paging request at ffff8dfcc0003000
IP: gup_pgd_range+0x1f0/0xc20
PGD 17ae72067 P4D 17ae72067 PUD 0
Oops: 0000 [#1] SMP PTI
...
CPU: 3 PID: 5467 Comm: hugetlb_1gb Not tainted 4.15.0-rc8-mm1-abc+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-1.fc25 04/01/2014
You can easily reproduce this by calling madvise(MADV_HWPOISON) twice on
a 1GB hugepage. This happens because get_user_pages_fast() is not aware
of a migration entry on pud that was created in the 1st madvise() event.
I think that conversion to pud-aligned migration entry is working, but
other MM code walking over page table isn't prepared for it. We need
some time and effort to make all this work properly, so this patch
avoids the reported bug by just disabling error handling for 1GB
hugepage.
[n-horiguchi@ah.jp.nec.com: v2] Link: http://lkml.kernel.org/r/1517284444-18149-1-git-send-email-n-horiguchi@ah.jp.nec.com Link: http://lkml.kernel.org/r/1517207283-15769-1-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Punit Agrawal <punit.agrawal@arm.com> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Tatashin [Thu, 5 Apr 2018 23:23:00 +0000 (16:23 -0700)]
mm/memory_hotplug: optimize memory hotplug
During memory hotplugging we traverse struct pages three times:
1. memset(0) in sparse_add_one_section()
2. loop in __add_section() to set do: set_page_node(page, nid); and
SetPageReserved(page);
3. loop in memmap_init_zone() to call __init_single_pfn()
This patch removes the first two loops, and leaves only loop 3. All
struct pages are initialized in one place, the same as it is done during
boot.
The benefits:
- We improve memory hotplug performance because we are not evicting the
cache several times and also reduce loop branching overhead.
- Remove condition from hotpath in __init_single_pfn(), that was added
in order to fix the problem that was reported by Bharata in the above
email thread, thus also improve performance during normal boot.
- Make memory hotplug more similar to the boot memory initialization
path because we zero and initialize struct pages only in one
function.
- Simplifies memory hotplug struct page initialization code, and thus
enables future improvements, such as multi-threading the
initialization of struct pages in order to improve hotplug
performance even further on larger machines.
[pasha.tatashin@oracle.com: v5] Link: http://lkml.kernel.org/r/20180228030308.1116-7-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180215165920.8570-7-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Tatashin [Thu, 5 Apr 2018 23:22:56 +0000 (16:22 -0700)]
mm/memory_hotplug: don't read nid from struct page during hotplug
During memory hotplugging the probe routine will leave struct pages
uninitialized, the same as it is currently done during boot. Therefore,
we do not want to access the inside of struct pages before
__init_single_page() is called during onlining.
Because during hotplug we know that pages in one memory block belong to
the same numa node, we can skip the checking. We should keep checking
for the boot case.
[pasha.tatashin@oracle.com: s/register_new_memory()/hotplug_memory_register()] Link: http://lkml.kernel.org/r/20180228030308.1116-6-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180215165920.8570-6-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Tatashin [Thu, 5 Apr 2018 23:22:52 +0000 (16:22 -0700)]
mm/memory_hotplug: optimize probe routine
When memory is hotplugged pages_correctly_reserved() is called to verify
that the added memory is present, this routine traverses through every
struct page and verifies that PageReserved() is set. This is a slow
operation especially if a large amount of memory is added.
Instead of checking every page, it is enough to simply check that the
section is present, has mapping (struct page array is allocated), and
the mapping is online.
In addition, we should not excpect that probe routine sets flags in
struct page, as the struct pages have not yet been initialized. The
initialization should be done in __init_single_page(), the same as
during boot.
Link: http://lkml.kernel.org/r/20180215165920.8570-5-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During boot we poison struct page memory in order to ensure that no one
is accessing this memory until the struct pages are initialized in
__init_single_page().
This patch adds more scrutiny to this checking by making sure that flags
do not equal the poison pattern when they are accessed. The pattern is
all ones.
Since node id is also stored in struct page, and may be accessed quite
early, we add this enforcement into page_to_nid() function as well.
Note, this is applicable only when NODE_NOT_IN_PAGE_FLAGS=n
[pasha.tatashin@oracle.com: v4] Link: http://lkml.kernel.org/r/20180215165920.8570-4-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180213193159.14606-4-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Tatashin [Thu, 5 Apr 2018 23:22:43 +0000 (16:22 -0700)]
x86/mm/memory_hotplug: determine block size based on the end of boot memory
Memory sections are combined into "memory block" chunks. These chunks
are the units upon which memory can be added and removed.
On x86, the new memory may be added after the end of the boot memory,
therefore, if block size does not align with end of boot memory, memory
hot-plugging/hot-removing can be broken.
Memory sections are combined into "memory block" chunks. These chunks
are the units upon which memory can be added and removed.
On x86 the new memory may be added after the end of the boot memory,
therefore, if block size does not align with end of boot memory, memory
hotplugging/hotremoving can be broken.
Currently, whenever machine is booted with more than 64G the block size
is unconditionally increased to 2G from the base 128M. This is done in
order to reduce number of memory device files in sysfs:
/sys/devices/system/memory/memoryXXX
We must use the largest allowed block size that aligns to the next
address to be able to hotplug the next block of memory.
So, when memory is larger or equal to 64G, we check the end address and
find the largest block size that is still power of two but smaller or
equal to 2G.
Before, the fix:
Run qemu with:
-m 64G,slots=2,maxmem=66G -object memory-backend-ram,id=mem1,size=2G
static bool pages_correctly_reserved(unsigned long start_pfn)
205 if (WARN_ON_ONCE(!pfn_valid(pfn)))
This function loops through every section in the newly added memory
block and verifies that the first pfn is valid, meaning section exists,
has mapping (struct page array), and is online.
The block size on x86 is usually 128M, but when machine is booted with
more than 64G of memory, the block size is changed to 2G: $ cat
/sys/devices/system/memory/block_size_bytes 80000000
During memory hotplug, and hotremove we verify that the range is section
size aligned, but we actually must verify that it is block size aligned,
because that is the proper unit for hotplug operations. See:
Documentation/memory-hotplug.txt
So, when the start_pfn of newly added memory is not block size aligned,
we can get a memory block that has only part of it with properly
populated sections.
In our case the start_pfn starts from the last_pfn (end of physical
memory).
Yang Shi [Thu, 5 Apr 2018 23:22:35 +0000 (16:22 -0700)]
mm: thp: fix potential clearing to referenced flag in page_idle_clear_pte_refs_one()
For PTE-mapped THP, the compound THP has not been split to normal 4K
pages yet, the whole THP is considered referenced if any one of sub page
is referenced.
When walking PTE-mapped THP by pvmw, all relevant PTEs will be checked
to retrieve referenced bit. But, the current code just returns the
result of the last PTE. If the last PTE has not referenced, the
referenced flag will be cleared.
Just set referenced when ptep{pmdp}_clear_young_notify() returns true.
Link: http://lkml.kernel.org/r/1518212451-87134-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reported-by: Gang Deng <gavin.dg@linux.alibaba.com> Suggested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> 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>
Pavel Tatashin [Thu, 5 Apr 2018 23:22:31 +0000 (16:22 -0700)]
mm: initialize pages on demand during boot
Deferred page initialization allows the boot cpu to initialize a small
subset of the system's pages early in boot, with other cpus doing the
rest later on.
It is, however, problematic to know how many pages the kernel needs
during boot. Different modules and kernel parameters may change the
requirement, so the boot cpu either initializes too many pages or runs
out of memory.
To fix that, initialize early pages on demand. This ensures the kernel
does the minimum amount of work to initialize pages during boot and
leaves the rest to be divided in the multithreaded initialization path
(deferred_init_memmap).
The on-demand code is permanently disabled using static branching once
deferred pages are initialized. After the static branch is changed to
false, the overhead is up-to two branch-always instructions if the zone
watermark check fails or if rmqueue fails.
Sergey Senozhatsky noticed that while deferred pages currently make
sense only on NUMA machines (we start one thread per latency node),
CONFIG_NUMA is not a requirement for CONFIG_DEFERRED_STRUCT_PAGE_INIT,
so that is also must be addressed in the patch.
[akpm@linux-foundation.org: fix typo in comment, make deferred_pages static]
[pasha.tatashin@oracle.com: fix min() type mismatch warning] Link: http://lkml.kernel.org/r/20180212164543.26592-1-pasha.tatashin@oracle.com
[pasha.tatashin@oracle.com: use zone_to_nid() in deferred_grow_zone()] Link: http://lkml.kernel.org/r/20180214163343.21234-2-pasha.tatashin@oracle.com
[pasha.tatashin@oracle.com: might_sleep warning] Link: http://lkml.kernel.org/r/20180306192022.28289-1-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: s/spin_lock/spin_lock_irq/ in page_alloc_init_late()]
[pasha.tatashin@oracle.com: v5] Link: http://lkml.kernel.org/r/20180309220807.24961-3-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: tweak comments]
[pasha.tatashin@oracle.com: v6] Link: http://lkml.kernel.org/r/20180313182355.17669-3-pasha.tatashin@oracle.com
[akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20180209192216.20509-2-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Steven Sistare <steven.sistare@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pavel Tatashin [Thu, 5 Apr 2018 23:22:27 +0000 (16:22 -0700)]
mm: disable interrupts while initializing deferred pages
Vlastimil Babka reported about a window issue during which when deferred
pages are initialized, and the current version of on-demand
initialization is finished, allocations may fail. While this is highly
unlikely scenario, since this kind of allocation request must be large,
and must come from interrupt handler, we still want to cover it.
We solve this by initializing deferred pages with interrupts disabled,
and holding node_size_lock spin lock while pages in the node are being
initialized. The on-demand deferred page initialization that comes
later will use the same lock, and thus synchronize with
deferred_init_memmap().
It is unlikely for threads that initialize deferred pages to be
interrupted. They run soon after smp_init(), but before modules are
initialized, and long before user space programs. This is why there is
no adverse effect of having these threads running with interrupts
disabled.
[pasha.tatashin@oracle.com: v6] Link: http://lkml.kernel.org/r/20180313182355.17669-2-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180309220807.24961-2-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Miles Chen <miles.chen@mediatek.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Randy Dunlap [Thu, 5 Apr 2018 23:22:23 +0000 (16:22 -0700)]
mm/swap_slots.c: use conditional compilation
For mm/swap_slots.c, use the traditional Linux method of conditional
compilation and linking instead of always compiling it by using #ifdef
CONFIG_SWAP and #endif for the entire source file (excluding header
files).
Link: http://lkml.kernel.org/r/c2a47015-0b5a-d0d9-8bc7-9984c049df20@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Tim Chen <tim.c.chen@linux.intel.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/migrate: rename migration reason MR_CMA to MR_CONTIG_RANGE
alloc_contig_range() initiates compaction and eventual migration for the
purpose of either CMA or HugeTLB allocations. At present, the reason
code remains the same MR_CMA for either of these cases. Let's make it
MR_CONTIG_RANGE which will appropriately reflect the reason code in both
these cases.
Link: http://lkml.kernel.org/r/20180202091518.18798-1-khandual@linux.vnet.ibm.com Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Colin Ian King [Thu, 5 Apr 2018 23:22:01 +0000 (16:22 -0700)]
mm/ksm.c: make stable_node_dup() static
stable_node_dup() is local to the source and does not need to be in
global scope, so make it static.
Cleans up sparse warning:
mm/ksm.c:1321:13: warning: symbol 'stable_node_dup' was not declared. Should it be static?
Link: http://lkml.kernel.org/r/20180206221005.12642-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The kasan quarantine is designed to delay freeing slab objects to catch
use-after-free. The quarantine can be large (several percent of machine
memory size). When kmem_caches are deleted related objects are flushed
from the quarantine but this requires scanning the entire quarantine
which can be very slow. We have seen the kernel busily working on this
while holding slab_mutex and badly affecting cache_reaper, slabinfo
readers and memcg kmem cache creations.
It can easily reproduced by following script:
yes . | head -1000000 | xargs stat > /dev/null
for i in `seq 1 10`; do
seq 500 | (cd /cg/memory && xargs mkdir)
seq 500 | xargs -I{} sh -c 'echo $BASHPID > \
/cg/memory/{}/tasks && exec stat .' > /dev/null
seq 500 | (cd /cg/memory && xargs rmdir)
done
This patch is based on the observation that if the kmem_cache to be
destroyed is empty then there should not be any objects of this cache in
the quarantine.
Without the patch the script got stuck for couple of hours. With the
patch the script completed within a second.
Link: http://lkml.kernel.org/r/20180327230603.54721-1-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Dmitry Vyukov <dvyukov@google.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>
mm/slab_common.c: remove test if cache name is accessible
Since commit db265eca7700 ("mm/sl[aou]b: Move duping of slab name to
slab_common.c"), the kernel always duplicates the slab cache name when
creating a slab cache, so the test if the slab name is accessible is
useless.
Link: http://lkml.kernel.org/r/alpine.LRH.2.02.1803231133310.22626@file01.intranet.prod.int.rdu2.redhat.com Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: 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>
However for SLUB in debug kernel, the sizes were same. On further
inspection it is found that SLUB always use kmem_cache.object_size to
measure the kmem_cache.size while SLAB use the given kmem_cache.size.
In the debug kernel the slab's size can be larger than its object_size.
Thus in the creation of non-root slab, the SLAB uses the root's size as
base to calculate the non-root slab's size and thus non-root slab's size
can be larger than the root slab's size. For SLUB, the non-root slab's
size is measured based on the root's object_size and thus the size will
remain same for root and non-root slab.
This patch makes slab's object_size the default base to measure the
slab's size.
Link: http://lkml.kernel.org/r/20180313165428.58699-1-shakeelb@google.com Fixes: 794b1248be4e ("memcg, slab: separate memcg vs root cache creation paths") Signed-off-by: Shakeel Butt <shakeelb@google.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: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If kmem case sizes are 32-bit, then usecopy region should be too.
Link: http://lkml.kernel.org/r/20180305200730.15812-21-adobriyan@gmail.com Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: David Miller <davem@davemloft.net> 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>
slab: make create_kmalloc_cache() work with 32-bit sizes
KMALLOC_MAX_CACHE_SIZE is 32-bit so is the largest kmalloc cache size.
Christoph said:
:
: Ok SLABs maximum allocation size is limited to 32M (see
: include/linux/slab.h:
:
: #define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
: (MAX_ORDER + PAGE_SHIFT - 1) : 25)
:
: And SLUB/SLOB pass all larger requests to the page allocator anyways.
Link: http://lkml.kernel.org/r/20180305200730.15812-4-adobriyan@gmail.com Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: 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>
This patch start a series of converting SLUB (mostly) to "unsigned int".
1) Most integers in the code are in fact unsigned entities: array
indexes, lengths, buffer sizes, allocation orders. It is therefore
better to use unsigned variables
2) Some integers in the code are either "size_t" or "unsigned long" for
no reason.
size_t usually comes from people trying to maintain type correctness
and figuring out that "sizeof" operator returns size_t or
memset/memcpy takes size_t so should everything passed to it.
However the number of 4GB+ objects in the kernel is very small. Most,
if not all, dynamically allocated objects with kmalloc() or
kmem_cache_create() aren't actually big. Maintaining wide types
doesn't do anything.
64-bit ops are bigger than 32-bit on our beloved x86_64,
so try to not use 64-bit where it isn't necessary
(read: everywhere where integers are integers not pointers)
3) in case of SLAB allocators, there are additional limitations
*) page->inuse, page->objects are only 16-/15-bit,
*) cache size was always 32-bit
*) slab orders are small, order 20 is needed to go 64-bit on x86_64
(PAGE_SIZE << order)
Basically everything is 32-bit except kmalloc(1ULL<<32) which gets
shortcut through page allocator.
Christoph said:
:
: That changes with large base page size on power and ARM64 f.e. but then
: we do not want to encourage larger allocations through slab anyways.
Link: http://lkml.kernel.org/r/20180305200730.15812-2-adobriyan@gmail.com Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: 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>
mm/slub.c: use jitter-free reference while printing age
When SLUB_DEBUG catches some issues, it prints all the required debug
info. However, in a few cases where allocation and free of the object
has happened in a very short time, 'age' might be misleading. See the
example below:
=============================================================================
BUG kmalloc-256 (Tainted: G W O ): Poison overwritten
-----------------------------------------------------------------------------
...
INFO: Allocated in binder_transaction+0x4b0/0x2448 age=731 cpu=3 pid=5314
...
INFO: Freed in binder_free_transaction+0x2c/0x58 age=735 cpu=6 pid=2079
...
Object fffffff14956a870: 6b 6b 6b 6b 6b 6b 6b 6b 67 6b 6b 6b 6b 6b 6b a5 kkkkkkkkgkkkk
In this case, object got freed later but 'age' shows otherwise. This
could be because, while printing this info, we print allocation traces
first and free traces thereafter. In between, if we get schedule out or
jiffies increment, (jiffies - t->when) could become meaningless.
Use the jitter free reference to calculate age.
New output will exactly be same. 'age' is still staying with single
jiffies ref in both prints.
Change-Id: I0846565807a4229748649bbecb1ffb743d71fcd8 Link: http://lkml.kernel.org/r/1520492010-19389-1-git-send-email-cpandya@codeaurora.org Signed-off-by: Chintan Pandya <cpandya@codeaurora.org> Acked-by: Christoph Lameter <cl@linux.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> 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>
fs: don't flush pagecache when expanding block device
When changing the size of a block device, its all caches are freed.
It's necessary on shrinking to prevent spurious I/Os to the disappeared
region. However, on expanding, such kind of I/Os doesn't happen.
Similar things can be considered for btrfs filesystem resize and
resize2fs, but they are designed not to drop caches when expanding.
Therefore this patch removes unnecessary cache drop.
Link: http://lkml.kernel.org/r/1521457240-153390-1-git-send-email-shunki-fujita@cybozu.co.jp Signed-off-by: Shunki Fujita <shunki-fujita@cybozu.co.jp> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
net/9p/client.c: fix potential refcnt problem of trans module
When specifying trans_mod multiple times in a mount, it will cause an
inaccurate refcount of the trans module. Also, in the error case of
option parsing, we should put the trans module if we have already got
it.
Link: http://lkml.kernel.org/r/1522154942-57339-1-git-send-email-cgxu519@gmx.com Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Miller <davem@davemloft.net> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the user uses some syscall, for example mmap(v9fs_file_mmap), it
will not update atime even if user's was set mnt_flags without
MNT_NOATIME, because v9fs defaults to settine SB_NOATIME in
v9fs_set_super.
For supporting access time updating when the user mounts with relatime,
we should not set SB_NOATIME by default.
Link: http://lkml.kernel.org/r/5AB9A377.6080906@huawei.com Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com> Reviewed-by: Greg Kurz <groug@kaod.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
9p: don't maintain dir i_nlink if the exported fs doesn't either
If the exported filesystem dir on 9p server doesn't maintain accurate
i_nlink count, e.g. always reports i_nlink as 1, then 9p should not
maintain nlink count either, otherwise drop_link would report warning
with i_nlink being zero.
For example:
- overlayfs sets nlink to 1 for merged dir
- ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has
more than EXT4_LINK_MAX (65000) links.
In this case, everytime a stat(2) call (getattr) on such exported dirs
on 9p client side, the i_nlink gets reset to 1, then operations like
rmdir(2), unlink(2) and rename(2) would cause the dir nlink to go to
zero (then negative), which results in warnings in drop_nlink() and/or
inc_nlink() calls.
This can be reproduced easily as the following steps:
- export a merged overlayfs dir via qemu virtfs to guest
- mount the exported virtfs in guest
- create two sub-directories in the root dir of the mounted 9pfs
- stat the root dir of 9pfs, this resets nlink to 1
- remove all subdirs, the second unlink/rmdir would trigger warning
Fix it by leaving i_nlink to be 1 and don't drop nlink if a directory
has nlink <= 2, which indicates that the underlying exported fs doesn't
maintain nlink count accurately. This follows what ext4 does in
ext4_dec_count().
Link: http://lkml.kernel.org/r/20180312053829.4367-1-eguan@linux.alibaba.com Signed-off-by: Eryu Guan <eguan@linux.alibaba.com> Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com> Tested-by: Roman Kapl <code@rkapl.cz> Cc: Caspar Zhang <caspar@linux.alibaba.com> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Cc: <v9fs-developer@lists.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Greg Kurz [Thu, 5 Apr 2018 23:19:44 +0000 (16:19 -0700)]
net/9p: avoid -ERESTARTSYS leak to userspace
If it was interrupted by a signal, the 9p client may need to send some
more requests to the server for cleanup before returning to userspace.
To avoid such a last minute request to be interrupted right away, the
client memorizes if a signal is pending, clears TIF_SIGPENDING, handles
the request and calls recalc_sigpending() before returning.
Unfortunately, if the transmission of this cleanup request fails for any
reason, the transport returns an error and the client propagates it
right away, without calling recalc_sigpending().
This ends up with -ERESTARTSYS from the initially interrupted request
crawling up to syscall exit, with TIF_SIGPENDING cleared by the cleanup
request. The specific signal handling code, which is responsible for
converting -ERESTARTSYS to -EINTR is not called, and userspace receives
the confusing errno value:
open: Unknown error 512 (512)
This is really hard to hit in real life. I discovered the issue while
working on hot-unplug of a virtio-9p-pci device with an instrumented
QEMU allowing to control request completion.
Both p9_client_zc_rpc() and p9_client_rpc() functions have this buggy
error path actually. Their code flow is a bit obscure and the best
thing to do would probably be a full rewrite: to really ensure this
situation of clearing TIF_SIGPENDING and returning -ERESTARTSYS can
never happen.
But given the general lack of interest for the 9p code, I won't risk
breaking more things. So this patch simply fixes the buggy paths in
both functions with a trivial label+goto.
Thanks to Laurent Dufour for his help and suggestions on how to find the
root cause and how to fix it.
Link: http://lkml.kernel.org/r/152062809886.10599.7361006774123053312.stgit@bahia.lan Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Yiwen Jiang <jiangyiwen@huawei.com> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Ron Minnich <rminnich@sandia.gov> Cc: Latchesar Ionkov <lucho@ionkov.net> Cc: David Miller <davem@davemloft.net> Cc: Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Changwei Ge [Thu, 5 Apr 2018 23:19:40 +0000 (16:19 -0700)]
ocfs2/dlm: clean up unused variable in dlm_process_recovery_data
Link: http://lkml.kernel.org/r/1522734135-7933-1-git-send-email-ge.changwei@h3c.com Signed-off-by: Changwei Ge <ge.changwei@h3c.com> Acked-by: Joseph Qi <jiangqi903@gmail.com> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Changwei Ge <ge.changwei@h3c.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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