Merge more patches from Andrew Morton:
"The rest of MM. Plus one misc cleanup"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits)
mm/Kconfig: add MMU dependency for MIGRATION.
kernel: replace strict_strto*() with kstrto*()
mm, thp: count thp_fault_fallback anytime thp fault fails
thp: consolidate code between handle_mm_fault() and do_huge_pmd_anonymous_page()
thp: do_huge_pmd_anonymous_page() cleanup
thp: move maybe_pmd_mkwrite() out of mk_huge_pmd()
mm: cleanup add_to_page_cache_locked()
thp: account anon transparent huge pages into NR_ANON_PAGES
truncate: drop 'oldsize' truncate_pagecache() parameter
mm: make lru_add_drain_all() selective
memcg: document cgroup dirty/writeback memory statistics
memcg: add per cgroup writeback pages accounting
memcg: check for proper lock held in mem_cgroup_update_page_stat
memcg: remove MEMCG_NR_FILE_MAPPED
memcg: reduce function dereference
memcg: avoid overflow caused by PAGE_ALIGN
memcg: rename RESOURCE_MAX to RES_COUNTER_MAX
memcg: correct RESOURCE_MAX to ULLONG_MAX
mm: memcg: do not trap chargers with full callstack on OOM
mm: memcg: rework and document OOM waiting and wakeup
...
Chen Gang [Thu, 12 Sep 2013 22:14:08 +0000 (15:14 -0700)]
mm/Kconfig: add MMU dependency for MIGRATION.
MIGRATION must depend on MMU, or allmodconfig for the nommu sh
architecture fails to build:
CC mm/migrate.o
mm/migrate.c: In function 'remove_migration_pte':
mm/migrate.c:134:3: error: implicit declaration of function 'pmd_trans_huge' [-Werror=implicit-function-declaration]
if (pmd_trans_huge(*pmd))
^
mm/migrate.c:149:2: error: implicit declaration of function 'is_swap_pte' [-Werror=implicit-function-declaration]
if (!is_swap_pte(pte))
^
...
Also let CMA depend on MMU, or when NOMMU, if we select CMA, it will
select MIGRATION by force.
Signed-off-by: Chen Gang <gang.chen@asianux.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Rientjes [Thu, 12 Sep 2013 22:14:06 +0000 (15:14 -0700)]
mm, thp: count thp_fault_fallback anytime thp fault fails
Currently, thp_fault_fallback in vmstat only gets incremented if a
hugepage allocation fails. If current's memcg hits its limit or the page
fault handler returns an error, it is incorrectly accounted as a
successful thp_fault_alloc.
Count thp_fault_fallback anytime the page fault handler falls back to
using regular pages and only count thp_fault_alloc when a hugepage has
actually been faulted.
Signed-off-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.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>
- unindent most code of the function by inverting one condition;
- streamline code no-error path;
- move insert error path outside normal code path;
- call radix_tree_preload_end() earlier;
No functional changes.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
thp: account anon transparent huge pages into NR_ANON_PAGES
We use NR_ANON_PAGES as base for reporting AnonPages to user. There's
not much sense in not accounting transparent huge pages there, but add
them on printing to user.
Let's account transparent huge pages in NR_ANON_PAGES in the first place.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Ning Qu <quning@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Chris Metcalf [Thu, 12 Sep 2013 22:13:55 +0000 (15:13 -0700)]
mm: make lru_add_drain_all() selective
make lru_add_drain_all() only selectively interrupt the cpus that have
per-cpu free pages that can be drained.
This is important in nohz mode where calling mlockall(), for example,
otherwise will interrupt every core unnecessarily.
This is important on workloads where nohz cores are handling 10 Gb traffic
in userspace. Those CPUs do not enter the kernel and place pages into LRU
pagevecs and they really, really don't want to be interrupted, or they
drop packets on the floor.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Reviewed-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add memcg routines to count writeback pages, later dirty pages will also
be accounted.
After Kame's commit 89c06bd52fb9 ("memcg: use new logic for page stat
accounting"), we can use 'struct page' flag to test page state instead
of per page_cgroup flag. But memcg has a feature to move a page from a
cgroup to another one and may have race between "move" and "page stat
accounting". So in order to avoid the race we have designed a new lock:
mem_cgroup_begin_update_page_stat()
modify page information -->(a)
mem_cgroup_update_page_stat() -->(b)
mem_cgroup_end_update_page_stat()
It requires both (a) and (b)(writeback pages accounting) to be pretected
in mem_cgroup_{begin/end}_update_page_stat(). It's full no-op for
!CONFIG_MEMCG, almost no-op if memcg is disabled (but compiled in), rcu
read lock in the most cases (no task is moving), and spin_lock_irqsave
on top in the slow path.
There're two writeback interfaces to modify: test_{clear/set}_page_writeback().
And the lock order is:
--> memcg->move_lock
--> mapping->tree_lock
memcg: check for proper lock held in mem_cgroup_update_page_stat
We should call mem_cgroup_begin_update_page_stat() before
mem_cgroup_update_page_stat() to get proper locks, however the latter
doesn't do any checking that we use proper locking, which would be hard.
Suggested by Michal Hock we could at least test for rcu_read_lock_held()
because RCU is held if !mem_cgroup_disabled().
While accounting memcg page stat, it's not worth to use
MEMCG_NR_FILE_MAPPED as an extra layer of indirection because of the
complexity and presumed performance overhead. We can use
MEM_CGROUP_STAT_FILE_MAPPED directly.
Since PAGE_ALIGN is aligning up(the next page boundary), so after
PAGE_ALIGN, the value might be overflow, such as write the MAX value to
*.limit_in_bytes.
Some user programs might depend on such behaviours(like libcg, we read
the value in snapshot, then use the value to reset cgroup later), and
that will cause confusion. So we need to fix it.
Signed-off-by: Sha Zhengju <handai.szj@taobao.com> Signed-off-by: Qiang Huang <h.huangqiang@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Jeff Liu <jeff.liu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current RESOURCE_MAX is ULONG_MAX, but the value we used to set resource
limit is unsigned long long, so we can set bigger value than that which is
strange. The XXX_MAX should be reasonable max value, bigger than that
should be overflow.
Notice that this change will affect user output of default *.limit_in_bytes:
before change:
Johannes Weiner [Thu, 12 Sep 2013 22:13:44 +0000 (15:13 -0700)]
mm: memcg: do not trap chargers with full callstack on OOM
The memcg OOM handling is incredibly fragile and can deadlock. When a
task fails to charge memory, it invokes the OOM killer and loops right
there in the charge code until it succeeds. Comparably, any other task
that enters the charge path at this point will go to a waitqueue right
then and there and sleep until the OOM situation is resolved. The problem
is that these tasks may hold filesystem locks and the mmap_sem; locks that
the selected OOM victim may need to exit.
For example, in one reported case, the task invoking the OOM killer was
about to charge a page cache page during a write(), which holds the
i_mutex. The OOM killer selected a task that was just entering truncate()
and trying to acquire the i_mutex:
The OOM handling task will retry the charge indefinitely while the OOM
killed task is not releasing any resources.
A similar scenario can happen when the kernel OOM killer for a memcg is
disabled and a userspace task is in charge of resolving OOM situations.
In this case, ALL tasks that enter the OOM path will be made to sleep on
the OOM waitqueue and wait for userspace to free resources or increase
the group's limit. But a userspace OOM handler is prone to deadlock
itself on the locks held by the waiting tasks. For example one of the
sleeping tasks may be stuck in a brk() call with the mmap_sem held for
writing but the userspace handler, in order to pick an optimal victim,
may need to read files from /proc/<pid>, which tries to acquire the same
mmap_sem for reading and deadlocks.
This patch changes the way tasks behave after detecting a memcg OOM and
makes sure nobody loops or sleeps with locks held:
1. When OOMing in a user fault, invoke the OOM killer and restart the
fault instead of looping on the charge attempt. This way, the OOM
victim can not get stuck on locks the looping task may hold.
2. When OOMing in a user fault but somebody else is handling it
(either the kernel OOM killer or a userspace handler), don't go to
sleep in the charge context. Instead, remember the OOMing memcg in
the task struct and then fully unwind the page fault stack with
-ENOMEM. pagefault_out_of_memory() will then call back into the
memcg code to check if the -ENOMEM came from the memcg, and then
either put the task to sleep on the memcg's OOM waitqueue or just
restart the fault. The OOM victim can no longer get stuck on any
lock a sleeping task may hold.
Debugged by Michal Hocko.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: azurIt <azurit@pobox.sk> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:43 +0000 (15:13 -0700)]
mm: memcg: rework and document OOM waiting and wakeup
The memcg OOM handler open-codes a sleeping lock for OOM serialization
(trylock, wait, repeat) because the required locking is so specific to
memcg hierarchies. However, it would be nice if this construct would be
clearly recognizable and not be as obfuscated as it is right now. Clean
up as follows:
1. Remove the return value of mem_cgroup_oom_unlock()
2. Rename mem_cgroup_oom_lock() to mem_cgroup_oom_trylock().
3. Pull the prepare_to_wait() out of the memcg_oom_lock scope. This
makes it more obvious that the task has to be on the waitqueue
before attempting to OOM-trylock the hierarchy, to not miss any
wakeups before going to sleep. It just didn't matter until now
because it was all lumped together into the global memcg_oom_lock
spinlock section.
4. Pull the mem_cgroup_oom_notify() out of the memcg_oom_lock scope.
It is proctected by the hierarchical OOM-lock.
5. The memcg_oom_lock spinlock is only required to propagate the OOM
lock in any given hierarchy atomically. Restrict its scope to
mem_cgroup_oom_(trylock|unlock).
6. Do not wake up the waitqueue unconditionally at the end of the
function. Only the lockholder has to wake up the next in line
after releasing the lock.
Note that the lockholder kicks off the OOM-killer, which in turn
leads to wakeups from the uncharges of the exiting task. But a
contender is not guaranteed to see them if it enters the OOM path
after the OOM kills but before the lockholder releases the lock.
Thus there has to be an explicit wakeup after releasing the lock.
7. Put the OOM task on the waitqueue before marking the hierarchy as
under OOM as that is the point where we start to receive wakeups.
No point in listening before being on the waitqueue.
8. Likewise, unmark the hierarchy before finishing the sleep, for
symmetry.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:40 +0000 (15:13 -0700)]
x86: finish user fault error path with fatal signal
The x86 fault handler bails in the middle of error handling when the
task has a fatal signal pending. For a subsequent patch this is a
problem in OOM situations because it relies on pagefault_out_of_memory()
being called even when the task has been killed, to perform proper
per-task OOM state unwinding.
Shortcutting the fault like this is a rather minor optimization that
saves a few instructions in rare cases. Just remove it for
user-triggered faults.
Use the opportunity to split the fault retry handling from actual fault
errors and add locking documentation that reads suprisingly similar to
ARM's.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:39 +0000 (15:13 -0700)]
arch: mm: pass userspace fault flag to generic fault handler
Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.
Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:38 +0000 (15:13 -0700)]
arch: mm: do not invoke OOM killer on kernel fault OOM
Kernel faults are expected to handle OOM conditions gracefully (gup,
uaccess etc.), so they should never invoke the OOM killer. Reserve this
for faults triggered in user context when it is the only option.
Most architectures already do this, fix up the remaining few.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:36 +0000 (15:13 -0700)]
arch: mm: remove obsolete init OOM protection
The memcg code can trap tasks in the context of the failing allocation
until an OOM situation is resolved. They can hold all kinds of locks
(fs, mm) at this point, which makes it prone to deadlocking.
This series converts memcg OOM handling into a two step process that is
started in the charge context, but any waiting is done after the fault
stack is fully unwound.
Patches 1-4 prepare architecture handlers to support the new memcg
requirements, but in doing so they also remove old cruft and unify
out-of-memory behavior across architectures.
Patch 5 disables the memcg OOM handling for syscalls, readahead, kernel
faults, because they can gracefully unwind the stack with -ENOMEM. OOM
handling is restricted to user triggered faults that have no other
option.
Patch 6 reworks memcg's hierarchical OOM locking to make it a little
more obvious wth is going on in there: reduce locked regions, rename
locking functions, reorder and document.
Patch 7 implements the two-part OOM handling such that tasks are never
trapped with the full charge stack in an OOM situation.
This patch:
Back before smart OOM killing, when faulting tasks were killed directly on
allocation failures, the arch-specific fault handlers needed special
protection for the init process.
Now that all fault handlers call into the generic OOM killer (see commit 609838cfed97: "mm: invoke oom-killer from remaining unconverted page
fault handlers"), which already provides init protection, the
arch-specific leftovers can be removed.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 12 Sep 2013 22:13:34 +0000 (15:13 -0700)]
memcg, vmscan: do not fall into reclaim-all pass too quickly
shrink_zone starts with soft reclaim pass first and then falls back to
regular reclaim if nothing has been scanned. This behavior is natural
but there is a catch. Memcg iterators, when used with the reclaim
cookie, are designed to help to prevent from over reclaim by
interleaving reclaimers (per node-zone-priority) so the tree walk might
miss many (even all) nodes in the hierarchy e.g. when there are direct
reclaimers racing with each other or with kswapd in the global case or
multiple allocators reaching the limit for the target reclaim case. To
make it even more complicated, targeted reclaim doesn't do the whole
tree walk because it stops reclaiming once it reclaims sufficient pages.
As a result groups over the limit might be missed, thus nothing is
scanned, and reclaim would fall back to the reclaim all mode.
This patch checks for the incomplete tree walk in shrink_zone. If no
group has been visited and the hierarchy is soft reclaimable then we
must have missed some groups, in which case the __shrink_zone is called
again. This doesn't guarantee there will be some progress of course
because the current reclaimer might be still racing with others but it
would at least give a chance to start the walk without a big risk of
reclaim latencies.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 12 Sep 2013 22:13:32 +0000 (15:13 -0700)]
memcg: track all children over limit in the root
Children in soft limit excess are currently tracked up the hierarchy in
memcg->children_in_excess. Nevertheless there still might exist tons of
groups that are not in hierarchy relation to the root cgroup (e.g. all
first level groups if root_mem_cgroup->use_hierarchy == false).
As the whole tree walk has to be done when the iteration starts at
root_mem_cgroup the iterator should be able to skip the walk if there is
no child above the limit without iterating them. This can be done
easily if the root tracks all children rather than only hierarchical
children. This is done by this patch which updates root_mem_cgroup
children_in_excess if root_mem_cgroup->use_hierarchy == false so the
root knows about all children in excess.
Please note that this is not an issue for inner memcgs which have
use_hierarchy == false because then only the single group is visited so
no special optimization is necessary.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 12 Sep 2013 22:13:30 +0000 (15:13 -0700)]
memcg, vmscan: do not attempt soft limit reclaim if it would not scan anything
mem_cgroup_should_soft_reclaim controls whether soft reclaim pass is
done and it always says yes currently. Memcg iterators are clever to
skip nodes that are not soft reclaimable quite efficiently but
mem_cgroup_should_soft_reclaim can be more clever and do not start the
soft reclaim pass at all if it knows that nothing would be scanned
anyway.
In order to do that, simply reuse mem_cgroup_soft_reclaim_eligible for
the target group of the reclaim and allow the pass only if the whole
subtree wouldn't be skipped.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 12 Sep 2013 22:13:28 +0000 (15:13 -0700)]
memcg: track children in soft limit excess to improve soft limit
Soft limit reclaim has to check the whole reclaim hierarchy while doing
the first pass of the reclaim. This leads to a higher system time which
can be visible especially when there are many groups in the hierarchy.
This patch adds a per-memcg counter of children in excess. It also
restores MEM_CGROUP_TARGET_SOFTLIMIT into mem_cgroup_event_ratelimit for a
proper batching.
If a group crosses soft limit for the first time it increases parent's
children_in_excess up the hierarchy. The similarly if a group gets below
the limit it will decrease the counter. The transition phase is recorded
in soft_contributed flag.
mem_cgroup_soft_reclaim_eligible then uses this information to better
decide whether to skip the node or the whole subtree. The rule is simple.
Skip the node with a children in excess or skip the whole subtree
otherwise.
This has been tested by a stream IO (dd if=/dev/zero of=file with
4*MemTotal size) which is quite sensitive to overhead during reclaim. The
load is running in a group with soft limit set to 0 and without any limit.
Apart from that there was a hierarchy with ~500, 2k and 8k groups (two
groups on each level) without any pages in them. base denotes to the
kernel on which the whole series is based on, rework is the kernel before
this patch and reworkoptim is with this patch applied:
System time is increased by 30-40% but it is reduced a lot comparing to
kernel without this patch. The higher time can be explained by the fact
that the original soft reclaim scanned at priority 0 so it was much more
effective for this workload (which is basically touch once and writeback).
The Elapsed time looks better though (~20%).
Both System and Elapsed are in stdev with the base kernel for all
configurations except for 8k where both System and Elapsed are up by 35%.
I do not have a good explanation for this because there is no soft reclaim
pass going on as no group is above the limit which is checked in
mem_cgroup_should_soft_reclaim.
Then I have tested kernel build with the same configuration to see the
behavior with a more general behavior.
Michal Hocko [Thu, 12 Sep 2013 22:13:26 +0000 (15:13 -0700)]
memcg: enhance memcg iterator to support predicates
The caller of the iterator might know that some nodes or even subtrees
should be skipped but there is no way to tell iterators about that so the
only choice left is to let iterators to visit each node and do the
selection outside of the iterating code. This, however, doesn't scale
well with hierarchies with many groups where only few groups are
interesting.
This patch adds mem_cgroup_iter_cond variant of the iterator with a
callback which gets called for every visited node. There are three
possible ways how the callback can influence the walk. Either the node is
visited, it is skipped but the tree walk continues down the tree or the
whole subtree of the current group is skipped.
[hughd@google.com: fix memcg-less page reclaim] Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 12 Sep 2013 22:13:25 +0000 (15:13 -0700)]
vmscan, memcg: do softlimit reclaim also for targeted reclaim
Soft reclaim has been done only for the global reclaim (both background
and direct). Since "memcg: integrate soft reclaim tighter with zone
shrinking code" there is no reason for this limitation anymore as the soft
limit reclaim doesn't use any special code paths and it is a part of the
zone shrinking code which is used by both global and targeted reclaims.
From the semantic point of view it is natural to consider soft limit
before touching all groups in the hierarchy tree which is touching the
hard limit because soft limit tells us where to push back when there is a
memory pressure. It is not important whether the pressure comes from the
limit or imbalanced zones.
This patch simply enables soft reclaim unconditionally in
mem_cgroup_should_soft_reclaim so it is enabled for both global and
targeted reclaim paths. mem_cgroup_soft_reclaim_eligible needs to learn
about the root of the reclaim to know where to stop checking soft limit
state of parents up the hierarchy. Say we have
A (over soft limit)
\
B (below s.l., hit the hard limit)
/ \
C D (below s.l.)
B is the source of the outside memory pressure now for D but we shouldn't
soft reclaim it because it is behaving well under B subtree and we can
still reclaim from C (pressumably it is over the limit).
mem_cgroup_soft_reclaim_eligible should therefore stop climbing up the
hierarchy at B (root of the memory pressure).
Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Glauber Costa <glommer@openvz.org> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michal Hocko [Thu, 12 Sep 2013 22:13:21 +0000 (15:13 -0700)]
memcg, vmscan: integrate soft reclaim tighter with zone shrinking code
This patchset is sitting out of tree for quite some time without any
objections. I would be really happy if it made it into 3.12. I do not
want to push it too hard but I think this work is basically ready and
waiting more doesn't help.
The basic idea is quite simple. Pull soft reclaim into shrink_zone in the
first step and get rid of the previous soft reclaim infrastructure.
shrink_zone is done in two passes now. First it tries to do the soft
limit reclaim and it falls back to reclaim-all mode if no group is over
the limit or no pages have been scanned. The second pass happens at the
same priority so the only time we waste is the memcg tree walk which has
been updated in the third step to have only negligible overhead.
As a bonus we will get rid of a _lot_ of code by this and soft reclaim
will not stand out like before when it wasn't integrated into the zone
shrinking code and it reclaimed at priority 0 (the testing results show
that some workloads suffers from such an aggressive reclaim). The clean
up is in a separate patch because I felt it would be easier to review that
way.
The second step is soft limit reclaim integration into targeted reclaim.
It should be rather straight forward. Soft limit has been used only for
the global reclaim so far but it makes sense for any kind of pressure
coming from up-the-hierarchy, including targeted reclaim.
The third step (patches 4-8) addresses the tree walk overhead by enhancing
memcg iterators to enable skipping whole subtrees and tracking number of
over soft limit children at each level of the hierarchy. This information
is updated same way the old soft limit tree was updated (from
memcg_check_events) so we shouldn't see an additional overhead. In fact
mem_cgroup_update_soft_limit is much simpler than tree manipulation done
previously.
__shrink_zone uses mem_cgroup_soft_reclaim_eligible as a predicate for
mem_cgroup_iter so the decision whether a particular group should be
visited is done at the iterator level which allows us to decide to skip
the whole subtree as well (if there is no child in excess). This reduces
the tree walk overhead considerably.
* TEST 1
========
My primary test case was a parallel kernel build with 2 groups (make is
running with -j8 with a distribution .config in a separate cgroup without
any hard limit) on a 32 CPU machine booted with 1GB memory and both builds
run taskset to Node 0 cpus.
I was mostly interested in 2 setups. Default - no soft limit set and -
and 0 soft limit set to both groups. The first one should tell us whether
the rework regresses the default behavior while the second one should show
us improvements in an extreme case where both workloads are always over
the soft limit.
/usr/bin/time -v has been used to collect the statistics and each
configuration had 3 runs after fresh boot without any other load on the
system.
base is mmotm-2013-07-18-16-40
rework all 8 patches applied on top of base
The improvement is really huge here (even bigger than with my previous
testing and I suspect that this highly depends on the storage). Page
fault statistics tell us at least part of the story:
Same as with my previous testing Minor faults are more or less within
noise but Major fault count is way bellow the base kernel.
While this looks as a nice win it is fair to say that 0-limit
configuration is quite artificial. So I was playing with 0-no-limit
loads as well.
* TEST 2
========
The following results are from 2 groups configuration on a 16GB machine
(single NUMA node).
- A running stream IO (dd if=/dev/zero of=local.file bs=1024) with
2*TotalMem with 0 soft limit.
- B running a mem_eater which consumes TotalMem-1G without any limit. The
mem_eater consumes the memory in 100 chunks with 1s nap after each
mmap+poppulate so that both loads have chance to fight for the memory.
The expected result is that B shouldn't be reclaimed and A shouldn't see
a big dropdown in elapsed time.
System time improved slightly as well as Elapsed. My previous testing
has shown worse numbers but this again seem to depend on the storage
speed.
My theory is that the writeback doesn't catch up and prio-0 soft reclaim
falls into wait on writeback page too often in the base kernel. The
patched kernel doesn't do that because the soft reclaim is done from the
kswapd/direct reclaim context. This can be seen on the following graph
nicely. The A's group usage_in_bytes regurarly drops really low very often.
All 3 runs
http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/stream.png
resp. a detail of the single run
http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/stream-one-run.png
mem_eater seems to be doing better as well. It gets to the full
allocation size faster as can be seen on the following graph:
http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/mem_eater-one-run.png
/proc/meminfo collected during the test also shows that rework kernel
hasn't swapped that much (well almost not at all):
base: max: 123900 K avg: 56388.29 K
rework: max: 300 K avg: 128.68 K
kswapd and direct reclaim statistics are of no use unfortunatelly because
soft reclaim is not accounted properly as the counters are hidden by
global_reclaim() checks in the base kernel.
* TEST 3
========
Another test was the same configuration as TEST2 except the stream IO was
replaced by a single kbuild (16 parallel jobs bound to Node0 cpus same as
in TEST1) and mem_eater allocated TotalMem-200M so kbuild had only 200MB
left.
Again we can see a significant improvement in Elapsed (it also seems to
be more stable), there is a huge dropdown for the Major page faults and
much more swapping:
base: max: 583736 K avg: 112547.43 K
rework: max: 4012 K avg: 124.36 K
Graphs from all three runs show the variability of the kbuild quite
nicely. It even seems that it took longer after every run with the base
kernel which would be quite surprising as the source tree for the build is
removed and caches are dropped after each run so the build operates on a
freshly extracted sources everytime.
http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/kbuild-mem_eater.png
My other testing shows that this is just a matter of timing and other runs
behave differently the std for Elapsed time is similar ~50. Example of
other three runs:
http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/kbuild-mem_eater2.png
So to wrap this up. The series is still doing good and improves the soft
limit.
The testing results for bunch of cgroups with both stream IO and kbuild
loads can be found in "memcg: track children in soft limit excess to
improve soft limit".
This patch:
Memcg soft reclaim has been traditionally triggered from the global
reclaim paths before calling shrink_zone. mem_cgroup_soft_limit_reclaim
then picked up a group which exceeds the soft limit the most and reclaimed
it with 0 priority to reclaim at least SWAP_CLUSTER_MAX pages.
The infrastructure requires per-node-zone trees which hold over-limit
groups and keep them up-to-date (via memcg_check_events) which is not cost
free. Although this overhead hasn't turned out to be a bottle neck the
implementation is suboptimal because mem_cgroup_update_tree has no idea
which zones consumed memory over the limit so we could easily end up
having a group on a node-zone tree having only few pages from that
node-zone.
This patch doesn't try to fix node-zone trees management because it seems
that integrating soft reclaim into zone shrinking sounds much easier and
more appropriate for several reasons. First of all 0 priority reclaim was
a crude hack which might lead to big stalls if the group's LRUs are big
and hard to reclaim (e.g. a lot of dirty/writeback pages). Soft reclaim
should be applicable also to the targeted reclaim which is awkward right
now without additional hacks. Last but not least the whole infrastructure
eats quite some code.
After this patch shrink_zone is done in 2 passes. First it tries to do
the soft reclaim if appropriate (only for global reclaim for now to keep
compatible with the original state) and fall back to ignoring soft limit
if no group is eligible to soft reclaim or nothing has been scanned during
the first pass. Only groups which are over their soft limit or any of
their parents up the hierarchy is over the limit are considered eligible
during the first pass.
Soft limit tree which is not necessary anymore will be removed in the
follow up patch to make this patch smaller and easier to review.
Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Glauber Costa <glommer@openvz.org> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ying Han <yinghan@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile 4 from Al Viro:
"list_lru pile, mostly"
This came out of Andrew's pile, Al ended up doing the merge work so that
Andrew didn't have to.
Additionally, a few fixes.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (42 commits)
super: fix for destroy lrus
list_lru: dynamically adjust node arrays
shrinker: Kill old ->shrink API.
shrinker: convert remaining shrinkers to count/scan API
staging/lustre/libcfs: cleanup linux-mem.h
staging/lustre/ptlrpc: convert to new shrinker API
staging/lustre/obdclass: convert lu_object shrinker to count/scan API
staging/lustre/ldlm: convert to shrinkers to count/scan API
hugepage: convert huge zero page shrinker to new shrinker API
i915: bail out earlier when shrinker cannot acquire mutex
drivers: convert shrinkers to new count/scan API
fs: convert fs shrinkers to new scan/count API
xfs: fix dquot isolation hang
xfs-convert-dquot-cache-lru-to-list_lru-fix
xfs: convert dquot cache lru to list_lru
xfs: rework buffer dispose list tracking
xfs-convert-buftarg-lru-to-generic-code-fix
xfs: convert buftarg LRU to generic code
fs: convert inode and dentry shrinking to be node aware
vmscan: per-node deferred work
...
Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC fixes from Olof Johansson:
"A small batch of fixes that have trickled in over the last week of the
merge window.
Also included are few small devicetree updates for sunxi, since it
enables me to use one of their newer boards (cubieboard2) for
additional test coverage. The support for that SoC is new for 3.12,
so there's no exposure to new regressions due to it"
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
ARM: dts: sun7i: olinuxino-micro: Enable the EMAC
ARM: dts: sun7i: cubieboard2: Enable the EMAC
ARM: dts: sun7i: Add the muxing options for the EMAC
ARM: dts: sun7i: Enable the Ethernet in the A20
i2c: davinci: Fix bad dev_get_platdata() conversion
ARM: vexpress: allow dcscb and tc2_pm in a combined ARMv6+v7 build
ARM: shmobile: lager: Do not use register_type field of struct sh_eth_plat_data
ARM: pxa: ssp: Check return values from phandle lookups
ARM: PCI: versatile: Fix SMAP register offsets
ARM: PCI: versatile: Fix PCI I/O
ARM: PCI: versatile: Fix map_irq function to match hardware
ARM: ep93xx: Don't use modem interface on the second UART
ARM: shmobile: r8a7779: Update early timer initialisation order
Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm
Pull ARM fixes from Russell King:
"Just two fixes here - one for the recent addition of Neon stuff which
causes problems when this is built as a module. The other was one
spotted by Olof with the fixed-HZ stuff.
Last patch (which is at the very top) is not a fix per-se, but an
almost-end-of-merge window sorting of the select symbols in
arch/arm/Kconfig to keep them as akpm would like to reduce unnecessary
conflicts. I've also taken the liberty this time to add a comment at
the end to discourage the endless "add the next select to the bottom
of a nicely sorted list" syndrome"
* 'fixes' of git://git.linaro.org/people/rmk/linux-arm:
ARM: sort arch/arm/Kconfig
ARM: fix forced-HZ values
ARM: 7835/2: fix modular build of xor_blocks() with NEON enabled
Merge tag 'nfs-for-3.12-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
Pull NFS client bugfixes (part 2) from Trond Myklebust:
"Bugfixes:
- Fix a few credential reference leaks resulting from the
SP4_MACH_CRED NFSv4.1 state protection code.
- Fix the SUNRPC bloatometer footprint: convert a 256K hashtable into
the intended 64 byte structure.
- Fix a long standing XDR issue with FREE_STATEID
- Fix a potential WARN_ON spamming issue
- Fix a missing dprintk() kuid conversion
New features:
- Enable the NFSv4.1 state protection support for the WRITE and
COMMIT operations"
* tag 'nfs-for-3.12-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
SUNRPC: No, I did not intend to create a 256KiB hashtable
sunrpc: Add missing kuids conversion for printing
NFSv4.1: sp4_mach_cred: WARN_ON -> WARN_ON_ONCE
NFSv4.1: sp4_mach_cred: no need to ref count creds
NFSv4.1: fix SECINFO* use of put_rpccred
NFSv4.1: sp4_mach_cred: ask for WRITE and COMMIT
NFSv4.1 fix decode_free_stateid
This avoids the spinlocks and refcounts in the d_path() sequence too
(used by /proc and various other entities). See commit 8b19e34188a3 for
the equivalent getcwd() system call path.
And unlike getcwd(), d_path() doesn't copy the result to user space, so
I don't need to fear _that_ particular bug happening again.
Russell King [Thu, 12 Sep 2013 20:24:42 +0000 (21:24 +0100)]
ARM: sort arch/arm/Kconfig
Keep arch/arm/Kconfig select statements sorted alphabetically. I've
added a comment at the bottom of the main bank for CONFIG_ARM to this
effect so hopefully this will keep things more in order.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
vfs: use __getname/__putname for getcwd() system call
It's a pathname. It should use the pathname allocators and
deallocators, and PATH_MAX instead of PAGE_SIZE. Never mind that the
two are commonly the same.
With this, the allocations scale up nicely too, and I can do getcwd()
system calls at a rate of about 300M/s, with no lock contention
anywhere.
Of course, nobody sane does that, especially since getcwd() is
traditionally a very slow operation in Unix. But this was also the
simplest way to benchmark the prepend_path() improvements by Waiman, and
once I saw the profiles I couldn't leave it well enough alone.
But apart from being an performance improvement (from using per-cpu slab
allocators instead of the raw page allocator), it's actually a valid and
real cleanup.
vfs: don't copy things to user space holding the rcu readlock
Oops. That wasn't very smart. We don't actually need the RCU lock any
more by the time we copy the cwd string to user space, but I had
stupidly surrounded the whole thing with it.
Introduced by commit 8b19e34188a3 ("vfs: make getcwd() get the root and
pwd path under rcu")
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds
Pull led updates from Bryan Wu:
"Sorry for the late pull request, since I'm just back from vacation.
LED subsystem updates for 3.12:
- pca9633 driver DT supporting and pca9634 chip supporting
- restore legacy device attributes for lp5521
- other fixing and updates"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds: (28 commits)
leds: wm831x-status: Request a REG resource
leds: trigger: ledtrig-backlight: Fix invalid memory access in fb_event notification callback
leds-pca963x: Fix device tree parsing
leds-pca9633: Rename to leds-pca963x
leds-pca9633: Add mutex to the ledout register
leds-pca9633: Unique naming of the LEDs
leds-pca9633: Add support for PCA9634
leds: lp5562: use LP55xx common macros for device attributes
Documentation: leds-lp5521,lp5523: update device attribute information
leds: lp5523: remove unnecessary writing commands
leds: lp5523: restore legacy device attributes
leds: lp5523: LED MUX configuration on initializing
leds: lp5523: make separate API for loading engine
leds: lp5521: remove unnecessary writing commands
leds: lp5521: restore legacy device attributes
leds: lp55xx: add common macros for device attributes
leds: lp55xx: add common data structure for program
Documentation: leds: Fix a typo
leds: ss4200: Fix incorrect placement of __initdata
leds: clevo-mail: Fix incorrect placement of __initdata
...
Merge tag 'stable/for-linus-3.12-rc0-tag-three' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull Xen balloon driver bug-fixes from Stefano Stabellini:
- fix a preemption bug in xen/balloon.c;
- remove an harmful BUG_ON in xen/balloon.c that can trigger in
non-erroneous situations.
* tag 'stable/for-linus-3.12-rc0-tag-three' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/balloon: remove BUG_ON in increase_reservation
xen/balloon: ensure preemption is disabled when using a scratch page
Merge tag 'pm+acpi-fixes-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes from Rafael Wysocki:
"All of these commits are fixes that have emerged recently and some of
them fix bugs introduced during this merge window.
Specifics:
1) ACPI-based PCI hotplug (ACPIPHP) fixes related to spurious events
After the recent ACPIPHP changes we've seen some interesting
breakage on a system that triggers device check notifications
during boot for non-existing devices. Although those
notifications are really spurious, we should be able to deal with
them nevertheless and that shouldn't introduce too much overhead.
Four commits to make that work properly.
2) Memory hotplug and hibernation mutual exclusion rework
This was maent to be a cleanup, but it happens to fix a classical
ABBA deadlock between system suspend/hibernation and ACPI memory
hotplug which is possible if they are started roughly at the same
time. Three commits rework memory hotplug so that it doesn't
acquire pm_mutex and make hibernation use device_hotplug_lock
which prevents it from racing with memory hotplug.
The ACPI LPSS driver crashes during boot on Apple Macbook Air with
Haswell that has slightly unusual BIOS configuration in which one
of the LPSS device's _CRS method doesn't return all of the
information expected by the driver. Fix from Mika Westerberg, for
stable.
4) ACPICA fix related to Store->ArgX operation
AML interpreter fix for obscure breakage that causes AML to be
executed incorrectly on some machines (observed in practice).
From Bob Moore.
5) ACPI core fix for PCI ACPI device objects lookup
There still are cases in which there is more than one ACPI device
object matching a given PCI device and we don't choose the one
that the BIOS expects us to choose, so this makes the lookup take
more criteria into account in those cases.
6) Fix to prevent cpuidle from crashing in some rare cases
If the result of cpuidle_get_driver() is NULL, which can happen on
some systems, cpuidle_driver_ref() will crash trying to use that
pointer and the Daniel Fu's fix prevents that from happening.
7) cpufreq fixes related to CPU hotplug
Stephen Boyd reported a number of concurrency problems with
cpufreq related to CPU hotplug which are addressed by a series of
fixes from Srivatsa S Bhat and Viresh Kumar.
8) cpufreq fix for time conversion in time_in_state attribute
Time conversion carried out by cpufreq when user space attempts to
read /sys/devices/system/cpu/cpu*/cpufreq/stats/time_in_state
won't work correcty if cputime_t doesn't map directly to jiffies.
Fix from Andreas Schwab.
9) Revert of a troublesome cpufreq commit
Commit 7c30ed5 (cpufreq: make sure frequency transitions are
serialized) was intended to address some known concurrency
problems in cpufreq related to the ordering of transitions, but
unfortunately it introduced several problems of its own, so I
decided to revert it now and address the original problems later
in a more robust way.
10) Intel Haswell CPU models for intel_pstate from Nell Hardcastle.
11) cpufreq fixes related to system suspend/resume
The recent cpufreq changes that made it preserve CPU sysfs
attributes over suspend/resume cycles introduced a possible NULL
pointer dereference that caused it to crash during the second
attempt to suspend. Three commits from Srivatsa S Bhat fix that
problem and a couple of related issues.
12) cpufreq locking fix
cpufreq_policy_restore() should acquire the lock for reading, but
it acquires it for writing. Fix from Lan Tianyu"
* tag 'pm+acpi-fixes-3.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (25 commits)
cpufreq: Acquire the lock in cpufreq_policy_restore() for reading
cpufreq: Prevent problems in update_policy_cpu() if last_cpu == new_cpu
cpufreq: Restructure if/else block to avoid unintended behavior
cpufreq: Fix crash in cpufreq-stats during suspend/resume
intel_pstate: Add Haswell CPU models
Revert "cpufreq: make sure frequency transitions are serialized"
cpufreq: Use signed type for 'ret' variable, to store negative error values
cpufreq: Remove temporary fix for race between CPU hotplug and sysfs-writes
cpufreq: Synchronize the cpufreq store_*() routines with CPU hotplug
cpufreq: Invoke __cpufreq_remove_dev_finish() after releasing cpu_hotplug.lock
cpufreq: Split __cpufreq_remove_dev() into two parts
cpufreq: Fix wrong time unit conversion
cpufreq: serialize calls to __cpufreq_governor()
cpufreq: don't allow governor limits to be changed when it is disabled
ACPI / bind: Prefer device objects with _STA to those without it
ACPI / hotplug / PCI: Avoid parent bus rescans on spurious device checks
ACPI / hotplug / PCI: Use _OST to notify firmware about notify status
ACPI / hotplug / PCI: Avoid doing too much for spurious notifies
ACPICA: Fix for a Store->ArgX when ArgX contains a reference to a field.
ACPI / hotplug / PCI: Don't trim devices before scanning the namespace
...
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Various fixes.
The -g perf report lockup you reported is only partially addressed,
patches that fix the excessive runtime are still being worked on"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86: Fix uncore PCI fixed counter handling
uprobes: Fix utask->depth accounting in handle_trampoline()
perf/x86: Add constraint for IVB CYCLE_ACTIVITY:CYCLES_LDM_PENDING
perf: Fix up MMAP2 buffer space reservation
perf tools: Add attr->mmap2 support
perf kvm: Fix sample_type manipulation
perf evlist: Fix id pos in perf_evlist__open()
perf trace: Handle perf.data files with no tracepoints
perf session: Separate progress bar update when processing events
perf trace: Check if MAP_32BIT is defined
perf hists: Fix formatting of long symbol names
perf evlist: Fix parsing with no sample_id_all bit set
perf tools: Add test for parsing with no sample_id_all bit
perf trace: Check control+C more often
vfs: make getcwd() get the root and pwd path under rcu
This allows us to skip all the crazy spinlocks and reference count
updates, and instead use the fs sequence read-lock to get an atomic
snapshot of the root and cwd information.
We might want to make the rule that "prepend_path()" is always called
with the RCU lock held, but the RCU lock nests fine and this is the
minimal fix.
Let's not pollute the include files with inline functions that are only
used in a single place. Especially not if we decide we might want to
change the semantics of said function to make it more efficient..
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs updates from Chris Mason:
"This is against 3.11-rc7, but was pulled and tested against your tree
as of yesterday. We do have two small incrementals queued up, but I
wanted to get this bunch out the door before I hop on an airplane.
This is a fairly large batch of fixes, performance improvements, and
cleanups from the usual Btrfs suspects.
We've included Stefan Behren's work to index subvolume UUIDs, which is
targeted at speeding up send/receive with many subvolumes or snapshots
in place. It closes a long standing performance issue that was built
in to the disk format.
Mark Fasheh's offline dedup work is also here. In this case offline
means the FS is mounted and active, but the dedup work is not done
inline during file IO. This is a building block where utilities are
able to ask the FS to dedup a series of extents. The kernel takes
care of verifying the data involved really is the same. Today this
involves reading both extents, but we'll continue to evolve the
patches"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (118 commits)
Btrfs: optimize key searches in btrfs_search_slot
Btrfs: don't use an async starter for most of our workers
Btrfs: only update disk_i_size as we remove extents
Btrfs: fix deadlock in uuid scan kthread
Btrfs: stop refusing the relocation of chunk 0
Btrfs: fix memory leak of uuid_root in free_fs_info
btrfs: reuse kbasename helper
btrfs: return btrfs error code for dev excl ops err
Btrfs: allow partial ordered extent completion
Btrfs: convert all bug_ons in free-space-cache.c
Btrfs: add support for asserts
Btrfs: adjust the fs_devices->missing count on unmount
Btrf: cleanup: don't check for root_refs == 0 twice
Btrfs: fix for patch "cleanup: don't check the same thing twice"
Btrfs: get rid of one BUG() in write_all_supers()
Btrfs: allocate prelim_ref with a slab allocater
Btrfs: pass gfp_t to __add_prelim_ref() to avoid always using GFP_ATOMIC
Btrfs: fix race conditions in BTRFS_IOC_FS_INFO ioctl
Btrfs: fix race between removing a dev and writing sbs
Btrfs: remove ourselves from the cluster list under lock
...
Waiman Long [Thu, 12 Sep 2013 14:55:35 +0000 (10:55 -0400)]
dcache: get/release read lock in read_seqbegin_or_lock() & friend
This patch modifies read_seqbegin_or_lock() and need_seqretry() to use
newly introduced read_seqlock_excl() and read_sequnlock_excl()
primitives so that they won't change the sequence number even if they
fall back to take the lock. This is OK as no change to the protected
data structure is being made.
It will prevent one fallback to lock taking from cascading into a series
of lock taking reducing performance because of the sequence number
change. It will also allow other sequence readers to go forward while
an exclusive reader lock is taken.
This patch also updates some of the inaccurate comments in the code.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
To: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Waiman Long [Thu, 12 Sep 2013 14:55:34 +0000 (10:55 -0400)]
seqlock: Add a new locking reader type
The sequence lock (seqlock) was originally designed for the cases where
the readers do not need to block the writers by making the readers retry
the read operation when the data change.
Since then, the use cases have been expanded to include situations where
a thread does not need to change the data (effectively a reader) at all
but have to take the writer lock because it can't tolerate changes to
the protected structure. Some examples are the d_path() function and
the getcwd() syscall in fs/dcache.c where the functions take the writer
lock on rename_lock even though they don't need to change anything in
the protected data structure at all. This is inefficient as a reader is
now blocking other sequence number reading readers from moving forward
by pretending to be a writer.
This patch tries to eliminate this inefficiency by introducing a new
type of locking reader to the seqlock locking mechanism. This new
locking reader will try to take an exclusive lock preventing other
writers and locking readers from going forward. However, it won't
affect the progress of the other sequence number reading readers as the
sequence number won't be changed.
Signed-off-by: Waiman Long <Waiman.Long@hp.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tag 'sound-3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ASoC: mc13783: add spi errata fix
ASoC: rsnd: fixup flag name of rsnd_scu_platform_info
ALSA: hda - Add CS4208 codec support for MacBook 6,1 and 6,2
ALSA: hda - Add Toshiba Satellite C870 to MSI blacklist
ASoC: fsl_spdif: Select regmap-mmio
ALSA: hda - unmute pin amplifier in infoframe setup for Haswell
ALSA: hda - define is_haswell() to check if a display audio codec is Haswell
ALSA: hda - Add dock speaker support for ASUS TX300
ASoC: kirkwood: change the compatible string of the kirkwood-i2s driver
ASoC: atmel: disable error interrupt
ASoC: fsl: imx-audmux: Do not call imx_audmux_parse_dt_defaults() on non-dt kernel
Pull watchdog updates from Wim Van Sebroeck:
- New watchdog driver for Allwinner A10/A13
- some devm_ioremap_resource simplifications
- a s3c2410_wdt change that removes the global variables
* git://www.linux-watchdog.org/linux-watchdog:
watchdog: s3c2410_wdt: simplify use of devm_ioremap_resource
watchdog: simplify platform_get_resource_byname/devm_ioremap_resource
watchdog: ts72xx_wdt: simplify use of devm_ioremap_resource
watchdog: nuc900_wdt.c: simplify use of devm_ioremap_resource
watchdog: sunxi: New watchdog driver for Allwinner A10/A13
watchdog: s3c2410_wdt: remove the global variables
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux
Pull thermal management updates from Zhang Rui:
"We have a lot of SOC changes and a few thermal core fixes this time.
The biggest change is about exynos thermal driver restructure. The
patch set adds TMU (Thermal management Unit) driver support for
exynos5440 platform. There are 3 instances of the TMU controllers so
necessary cleanup/re-structure is done to handle multiple thermal
zone.
The next biggest change is the introduction of the imx thermal driver.
It adds the imx thermal support using Temperature Monitor (TEMPMON)
block found on some Freescale i.MX SoCs. The driver uses syscon
regmap interface to access TEMPMON control registers and calibration
data, and supports cpufreq as the cooling device.
Highlights:
- restructure exynos thermal driver.
- introduce new imx thermal driver.
- fix a bug in thermal core, which powers on the fans unexpectedly
after resume from suspend"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: (46 commits)
drivers: thermal: add check when unregistering cpu cooling
thermal: thermal_core: allow binding with limits on bind_params
drivers: thermal: make usage of CONFIG_THERMAL_HWMON optional
drivers: thermal: parent virtual hwmon with thermal zone
thermal: hwmon: move hwmon support to single file
thermal: exynos: Clean up non-DT remnants
thermal: exynos: Fix potential NULL pointer dereference
thermal: exynos: Fix typos in Kconfig
thermal: ti-soc-thermal: Ensure to compute thermal trend
thermal: ti-soc-thermal: Set the bandgap mask counter delay value
thermal: ti-soc-thermal: Initialize counter_delay field for TI DRA752 sensors
thermal: step_wise: return instance->target by default
thermal: step_wise: cdev only needs update on a new target state
Thermal/cpu_cooling: Return directly for the cpu out of allowed_cpus in the cpufreq_thermal_notifier()
thermal: exynos_tmu: fix wrong error check for mapped memory
thermal: imx: implement thermal alarm interrupt handling
thermal: imx: dynamic passive and SoC specific critical trip points
Documentation: thermal: Explain the exynos thermal driver model
ARM: dts: thermal: exynos: Add documentation for Exynos SoC thermal bindings
thermal: exynos: Support for TMU regulator defined at device tree
...
Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6
Pull CIFS fixes from Steve French:
"CIFS update including case insensitive file name matching improvements
for UTF-8 to Unicode, various small cifs fixes, SMB2/SMB3 leasing
improvements, support for following SMB2 symlinks, SMB3 packet signing
improvements"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6: (25 commits)
CIFS: Respect epoch value from create lease context v2
CIFS: Add create lease v2 context for SMB3
CIFS: Move parsing lease buffer to ops struct
CIFS: Move creating lease buffer to ops struct
CIFS: Store lease state itself rather than a mapped oplock value
CIFS: Replace clientCanCache* bools with an integer
[CIFS] quiet sparse compile warning
cifs: Start using per session key for smb2/3 for signature generation
cifs: Add a variable specific to NTLMSSP for key exchange.
cifs: Process post session setup code in respective dialect functions.
CIFS: convert to use le32_add_cpu()
CIFS: Fix missing lease break
CIFS: Fix a memory leak when a lease break comes
cifs: add winucase_convert.pl to Documentation/ directory
cifs: convert case-insensitive dentry ops to use new case conversion routines
cifs: add new case-insensitive conversion routines that are based on wchar_t's
[CIFS] Add Scott to list of cifs contributors
cifs: Move and expand MAX_SERVER_SIZE definition
cifs: Expand max share name length to 256
cifs: Move string length definitions to uapi
...
Commit 05b016ecf5e7a "ARC: Setup Vector Table Base in early boot" moved
the Interrupt vector Table setup out of arc_init_IRQ() which is called
for all CPUs, to entry point of boot cpu only, breaking booting of others.
Fix by adding the same to entry point of non-boot CPUs too.
read_arc_build_cfg_regs() printing IVT Base Register didn't help the
casue since it prints a synthetic value if zero which is totally bogus,
so fix that to print the exact Register.
[vgupta: Remove the now stale comment from header of arc_init_IRQ and
also added the commentary for halt-on-reset]
net/sunrpc/auth_generic.c: In function ‘generic_key_timeout’:
net/sunrpc/auth_generic.c:241: warning: format ‘%d’ expects type ‘int’, but
argument 2 has type ‘kuid_t’
* pm-cpufreq:
cpufreq: Acquire the lock in cpufreq_policy_restore() for reading
cpufreq: Prevent problems in update_policy_cpu() if last_cpu == new_cpu
cpufreq: Restructure if/else block to avoid unintended behavior
cpufreq: Fix crash in cpufreq-stats during suspend/resume
There was a bug in the handling of SNB-EP/IVB-EP uncore PCI
fixed counters, e.g., IMC.
It would cause erratic values to be returned for the IMC
clockticks event. This was due to a bogus hwc->config value
which was then written to PCI config space.
The erratic values can be seen via:
$ perf stat -a -C 0 -e uncore_imc_0/clockticks/ -I 1000 sleep 10
The fixed counter has most fields marked as reserved with
hw reset values of 0. Yet the kernel was defaulting to a
hwc->config = ~0 and that was causing the issues.
This patch sets the hwc->config values for fixed uncore event
to 0. Now, the values of IMC clockticks is correct.
uprobes: Fix utask->depth accounting in handle_trampoline()
Currently utask->depth is simply the number of allocated/pending
return_instance's in uprobe_task->return_instances list.
handle_trampoline() should decrement this counter every time we
handle/free an instance, but due to typo it does this only if
->chained == T. This means that in the likely case this counter
is never decremented and the probed task can't report more than
MAX_URETPROBE_DEPTH events.
Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
* Handle perf.data files with no tracepoints in 'perf trace', fixing a
segfault.
* Fix up MMAP2 buffer space reservation, a problem that was caught via
'perf test' consistency tests.
* Add attr->mmap2 support in the tools, a patch that should've been merged
together with the kernel counterpart:
13d7a24 "perf: Add attr->mmap2 attribute to an event".
Merging it allowed us to catch the MMAP buffer space reservation problem via
'perf test'. From Stephane Eranian.
The tools deals with older kernels by disabling this feature, resetting the
perf_event_attr.mmap2 bit, when -EINVAL is returned by perf_event_open, just
like with perf_event_attr.{sample_id_all,exclude_{guest,host}}.
When such fallback happens the perf_missing_features.mmap2 flag is set to
true and can be used by tooling that strictly needs this feature to check
for its availability on the running kernel.
* Make sure we can find PERF_SAMPLE_ID in the variable part of PERF_RECORD_
ring buffer records in 'perf kvm', where direct manipulation of sample_type
was being done.
Fixed by making use of the perf_evlist__set_sample_bit() helper and by
setting the evlist->id_pos in perf_evlist__open(), from Adrian Hunter.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
This reverts the Linux for Workgroups thing. And no, before somebody
asks, we're not doing Linux95. Not for a few years, at least.
Sure, the flag added some color to the logo, and could have remained as
a testament to my leet gimp skills. But no. And I'll do this early, to
avoid the chance of forgetting when I'm doing the actual rc1 release on
the road.
Merge tag 'ecryptfs-3.12-rc1-crypt-ctx' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs
Pull eCryptfs fixes from Tyler Hicks:
"Two small fixes to the code that initializes the per-file crypto
contexts"
* tag 'ecryptfs-3.12-rc1-crypt-ctx' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
ecryptfs: avoid ctx initialization race
ecryptfs: remove check for if an array is NULL
Merge branch 'for-v3.12-fix' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping
Pull DMA-mapping fix from Marek Szyprowski:
"A build bugfix for the device tree support for reserved memory
regions. Due to superfluous include the common code failed to build
on ARM64 and MIPS architectures.
The patch that caused the build break has lived at linux-next for
about two weeks and noone noticed the issue, what convinced me that
everything was ok"
* 'for-v3.12-fix' of git://git.linaro.org/people/mszyprowski/linux-dma-mapping:
drivers: of: fix build break if asm/dma-contiguous.h is missing
Merge tag 'for-3.12' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf
Pull dma-buf updates from Sumit Semwal:
"Yet another small one - dma-buf framework now supports size discovery
of the buffer via llseek"
* tag 'for-3.12' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf:
dma-buf: Expose buffer size to userspace (v2)
dma-buf: Check return value of anon_inode_getfile
Merge first patch-bomb from Andrew Morton:
- Some pidns/fork/exec tweaks
- OCFS2 updates
- Most of MM - there remain quite a few memcg parts which depend on
pending core cgroups changes. Which might have been already merged -
I'll check tomorrow...
- Various misc stuff all over the place
- A few block bits which I never got around to sending to Jens -
relatively minor things.
- MAINTAINERS maintenance
- A small number of lib/ updates
- checkpatch updates
- epoll
- firmware/dmi-scan
- Some kprobes work for S390
- drivers/rtc updates
- hfsplus feature work
- vmcore feature work
- rbtree upgrades
- AOE updates
- pktcdvd cleanups
- PPS
- memstick
- w1
- New "inittmpfs" feature, which does the obvious
- More IPC work from Davidlohr.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (303 commits)
lz4: fix compression/decompression signedness mismatch
ipc: drop ipc_lock_check
ipc, shm: drop shm_lock_check
ipc: drop ipc_lock_by_ptr
ipc, shm: guard against non-existant vma in shmdt(2)
ipc: document general ipc locking scheme
ipc,msg: drop msg_unlock
ipc: rename ids->rw_mutex
ipc,shm: shorten critical region for shmat
ipc,shm: cleanup do_shmat pasta
ipc,shm: shorten critical region for shmctl
ipc,shm: make shmctl_nolock lockless
ipc,shm: introduce shmctl_nolock
ipc: drop ipcctl_pre_down
ipc,shm: shorten critical region in shmctl_down
ipc,shm: introduce lockless functions to obtain the ipc object
initmpfs: use initramfs if rootfstype= or root= specified
initmpfs: make rootfs use tmpfs when CONFIG_TMPFS enabled
initmpfs: move rootfs code from fs/ramfs/ to init/
initmpfs: move bdi setup from init_rootfs to init_ramfs
...
LZ4 compression and decompression functions require different in
signedness input/output parameters: unsigned char for compression and
signed char for decompression.
Change decompression API to require "(const) unsigned char *".
After previous cleanups and optimizations, this function is no longer
heavily used and we don't have a good reason to keep it. Update the few
remaining callers and get rid of it.
As suggested by Andrew, add a generic initial locking scheme used
throughout all sysv ipc mechanisms. Documenting the ids rwsem, how rcu
can be enough to do the initial checks and when to actually acquire the
kern_ipc_perm.lock spinlock.
I found that adding it to util.c was generic enough.
Clean up some of the messy do_shmat() spaghetti code, getting rid of
out_free and out_put_dentry labels. This makes shortening the critical
region of this function in the next patch a little easier to do and read.
With the *_INFO, *_STAT, IPC_RMID and IPC_SET commands already optimized,
deal with the remaining SHM_LOCK and SHM_UNLOCK commands. Take the
shm_perm lock after doing the initial auditing and security checks. The
rest of the logic remains unchanged.
While the INFO cmd doesn't take the ipc lock, the STAT commands do acquire
it unnecessarily. We can do the permissions and security checks only
holding the rcu lock.
Similar to semctl and msgctl, when calling msgctl, the *_INFO and *_STAT
commands can be performed without acquiring the ipc object.
Add a shmctl_nolock() function and move the logic of *_INFO and *_STAT out
of msgctl(). Since we are just moving functionality, this change still
takes the lock and it will be properly lockless in the next patch.
ipc,shm: introduce lockless functions to obtain the ipc object
This is the third and final patchset that deals with reducing the amount
of contention we impose on the ipc lock (kern_ipc_perm.lock). These
changes mostly deal with shared memory, previous work has already been
done for semaphores and message queues:
With these patches applied, a custom shm microbenchmark stressing shmctl
doing IPC_STAT with 4 threads a million times, reduces the execution
time by 50%. A similar run, this time with IPC_SET, reduces the
execution time from 3 mins and 35 secs to 27 seconds.
Patches 1-8: replaces blindly taking the ipc lock for a smarter
combination of rcu and ipc_obtain_object, only acquiring the spinlock
when updating.
Patch 9: renames the ids rw_mutex to rwsem, which is what it already was.
Patch 10: is a trivial mqueue leftover cleanup
Patch 11: adds a brief lock scheme description, requested by Andrew.
This patch:
Add shm_obtain_object() and shm_obtain_object_check(), which will allow us
to get the ipc object without acquiring the lock. Just as with other
forms of ipc, these functions are basically wrappers around
ipc_obtain_object*().
Rob Landley [Wed, 11 Sep 2013 21:26:13 +0000 (14:26 -0700)]
initmpfs: use initramfs if rootfstype= or root= specified
Command line option rootfstype=ramfs to obtain old initramfs behavior, and
use ramfs instead of tmpfs for stub when root= defined (for cosmetic
reasons).
[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Rob Landley <rob@landley.net> Cc: Jeff Layton <jlayton@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Stephen Warren <swarren@nvidia.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jim Cromie <jim.cromie@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rob Landley [Wed, 11 Sep 2013 21:26:10 +0000 (14:26 -0700)]
initmpfs: move rootfs code from fs/ramfs/ to init/
When the rootfs code was a wrapper around ramfs, having them in the same
file made sense. Now that it can wrap another filesystem type, move it in
with the init code instead.
This also allows a subsequent patch to access rootfstype= command line
arg.
Signed-off-by: Rob Landley <rob@landley.net> Cc: Jeff Layton <jlayton@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Stephen Warren <swarren@nvidia.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jim Cromie <jim.cromie@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rob Landley [Wed, 11 Sep 2013 21:26:08 +0000 (14:26 -0700)]
initmpfs: move bdi setup from init_rootfs to init_ramfs
Even though ramfs hasn't got a backing device, commit e0bf68ddec4f ("mm:
bdi init hooks") added one anyway, and put the initialization in
init_rootfs() since that's the first user, leaving it out of init_ramfs()
to avoid duplication.
But initmpfs uses init_tmpfs() instead, so move the init into the
filesystem's init function, add a "once" guard to prevent duplicate
initialization, and call the filesystem init from rootfs init.
This goes part of the way to allowing ramfs to be built as a module.
[akpm@linux-foundation.org; using bit 1 was odd] Signed-off-by: Rob Landley <rob@landley.net> Cc: Jeff Layton <jlayton@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Stephen Warren <swarren@nvidia.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jim Cromie <jim.cromie@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jan Kara [Wed, 11 Sep 2013 21:26:05 +0000 (14:26 -0700)]
lib/radix-tree.c: make radix_tree_node_alloc() work correctly within interrupt
With users of radix_tree_preload() run from interrupt (block/blk-ioc.c is
one such possible user), the following race can happen:
radix_tree_preload()
...
radix_tree_insert()
radix_tree_node_alloc()
if (rtp->nr) {
ret = rtp->nodes[rtp->nr - 1];
<interrupt>
...
radix_tree_preload()
...
radix_tree_insert()
radix_tree_node_alloc()
if (rtp->nr) {
ret = rtp->nodes[rtp->nr - 1];
And we give out one radix tree node twice. That clearly results in radix
tree corruption with different results (usually OOPS) depending on which
two users of radix tree race.
We fix the problem by making radix_tree_node_alloc() always allocate fresh
radix tree nodes when in interrupt. Using preloading when in interrupt
doesn't make sense since all the allocations have to be atomic anyway and
we cannot steal nodes from process-context users because some users rely
on radix_tree_insert() succeeding after radix_tree_preload().
in_interrupt() check is somewhat ugly but we cannot simply key off passed
gfp_mask as that is acquired from root_gfp_mask() and thus the same for
all preload users.
Another part of the fix is to avoid node preallocation in
radix_tree_preload() when passed gfp_mask doesn't allow waiting. Again,
preallocation in such case doesn't make sense and when preallocation would
happen in interrupt we could possibly leak some allocated nodes. However,
some users of radix_tree_preload() require following radix_tree_insert()
to succeed. To avoid unexpected effects for these users,
radix_tree_preload() only warns if passed gfp mask doesn't allow waiting
and we provide a new function radix_tree_maybe_preload() for those users
which get different gfp mask from different call sites and which are
prepared to handle radix_tree_insert() failure.
Signed-off-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
projects / mirror_ubuntu-eoan-kernel.git / log