linux-stable.git/mm/filemap.c, branch v3.17.2 Linux kernel stable tree Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-08-11T18:44:11+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-08-11T18:44:11+00:00 f6f993328b2abcab86a3c99d7bd9f2066ab03d36 Pull vfs updates from Al Viro: "Stuff in here: - acct.c fixes and general rework of mnt_pin mechanism. That allows to go for delayed-mntput stuff, which will permit mntput() on deep stack without worrying about stack overflows - fs shutdown will happen on shallow stack. IOW, we can do Eric's umount-on-rmdir series without introducing tons of stack overflows on new mntput() call chains it introduces. - Bruce's d_splice_alias() patches - more Miklos' rename() stuff. - a couple of regression fixes (stable fodder, in the end of branch) and a fix for API idiocy in iov_iter.c. There definitely will be another pile, maybe even two. I'd like to get Eric's series in this time, but even if we miss it, it'll go right in the beginning of for-next in the next cycle - the tricky part of prereqs is in this pile" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits) fix copy_tree() regression __generic_file_write_iter(): fix handling of sync error after DIO switch iov_iter_get_pages() to passing maximal number of pages fs: mark __d_obtain_alias static dcache: d_splice_alias should detect loops exportfs: update Exporting documentation dcache: d_find_alias needn't recheck IS_ROOT && DCACHE_DISCONNECTED dcache: remove unused d_find_alias parameter dcache: d_obtain_alias callers don't all want DISCONNECTED dcache: d_splice_alias should ignore DCACHE_DISCONNECTED dcache: d_splice_alias mustn't create directory aliases dcache: close d_move race in d_splice_alias dcache: move d_splice_alias namei: trivial fix to vfs_rename_dir comment VFS: allow ->d_manage() to declare -EISDIR in rcu_walk mode. cifs: support RENAME_NOREPLACE hostfs: support rename flags shmem: support RENAME_EXCHANGE shmem: support RENAME_NOREPLACE btrfs: add RENAME_NOREPLACE ... 
Pull vfs updates from Al Viro:
 "Stuff in here:

   - acct.c fixes and general rework of mnt_pin mechanism.  That allows
     to go for delayed-mntput stuff, which will permit mntput() on deep
     stack without worrying about stack overflows - fs shutdown will
     happen on shallow stack.  IOW, we can do Eric's umount-on-rmdir
     series without introducing tons of stack overflows on new mntput()
     call chains it introduces.
   - Bruce's d_splice_alias() patches
   - more Miklos' rename() stuff.
   - a couple of regression fixes (stable fodder, in the end of branch)
     and a fix for API idiocy in iov_iter.c.

  There definitely will be another pile, maybe even two.  I'd like to
  get Eric's series in this time, but even if we miss it, it'll go right
  in the beginning of for-next in the next cycle - the tricky part of
  prereqs is in this pile"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits)
  fix copy_tree() regression
  __generic_file_write_iter(): fix handling of sync error after DIO
  switch iov_iter_get_pages() to passing maximal number of pages
  fs: mark __d_obtain_alias static
  dcache: d_splice_alias should detect loops
  exportfs: update Exporting documentation
  dcache: d_find_alias needn't recheck IS_ROOT && DCACHE_DISCONNECTED
  dcache: remove unused d_find_alias parameter
  dcache: d_obtain_alias callers don't all want DISCONNECTED
  dcache: d_splice_alias should ignore DCACHE_DISCONNECTED
  dcache: d_splice_alias mustn't create directory aliases
  dcache: close d_move race in d_splice_alias
  dcache: move d_splice_alias
  namei: trivial fix to vfs_rename_dir comment
  VFS: allow ->d_manage() to declare -EISDIR in rcu_walk mode.
  cifs: support RENAME_NOREPLACE
  hostfs: support rename flags
  shmem: support RENAME_EXCHANGE
  shmem: support RENAME_NOREPLACE
  btrfs: add RENAME_NOREPLACE
  ...
__generic_file_write_iter(): fix handling of sync error after DIO 2014-08-11T16:27:40+00:00 Al Viro viro@zeniv.linux.org.uk 2014-08-08T16:39:16+00:00 60bb45297f7551833346c5cebc6d483ea17ea5f2 If DIO results in short write and sync write fails, we want to bugger off whether the DIO part has written anything or not; the logics on the return will take care of the right return value. Cc: stable@vger.kernel.org [3.16] Reported-by: Anton Altaparmakov <aia21@cam.ac.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
If DIO results in short write and sync write fails, we want to bugger off
whether the DIO part has written anything or not; the logics on the return
will take care of the right return value.

Cc: stable@vger.kernel.org [3.16]
Reported-by: Anton Altaparmakov <aia21@cam.ac.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
mm: memcontrol: rewrite uncharge API 2014-08-08T22:57:17+00:00 Johannes Weiner hannes@cmpxchg.org 2014-08-08T21:19:22+00:00 0a31bc97c80c3fa87b32c091d9a930ac19cd0c40 The memcg uncharging code that is involved towards the end of a page's lifetime - truncation, reclaim, swapout, migration - is impressively complicated and fragile. Because anonymous and file pages were always charged before they had their page->mapping established, uncharges had to happen when the page type could still be known from the context; as in unmap for anonymous, page cache removal for file and shmem pages, and swap cache truncation for swap pages. However, these operations happen well before the page is actually freed, and so a lot of synchronization is necessary: - Charging, uncharging, page migration, and charge migration all need to take a per-page bit spinlock as they could race with uncharging. - Swap cache truncation happens during both swap-in and swap-out, and possibly repeatedly before the page is actually freed. This means that the memcg swapout code is called from many contexts that make no sense and it has to figure out the direction from page state to make sure memory and memory+swap are always correctly charged. - On page migration, the old page might be unmapped but then reused, so memcg code has to prevent untimely uncharging in that case. Because this code - which should be a simple charge transfer - is so special-cased, it is not reusable for replace_page_cache(). But now that charged pages always have a page->mapping, introduce mem_cgroup_uncharge(), which is called after the final put_page(), when we know for sure that nobody is looking at the page anymore. For page migration, introduce mem_cgroup_migrate(), which is called after the migration is successful and the new page is fully rmapped. Because the old page is no longer uncharged after migration, prevent double charges by decoupling the page's memcg association (PCG_USED and pc->mem_cgroup) from the page holding an actual charge. The new bits PCG_MEM and PCG_MEMSW represent the respective charges and are transferred to the new page during migration. mem_cgroup_migrate() is suitable for replace_page_cache() as well, which gets rid of mem_cgroup_replace_page_cache(). However, care needs to be taken because both the source and the target page can already be charged and on the LRU when fuse is splicing: grab the page lock on the charge moving side to prevent changing pc->mem_cgroup of a page under migration. Also, the lruvecs of both pages change as we uncharge the old and charge the new during migration, and putback may race with us, so grab the lru lock and isolate the pages iff on LRU to prevent races and ensure the pages are on the right lruvec afterward. Swap accounting is massively simplified: because the page is no longer uncharged as early as swap cache deletion, a new mem_cgroup_swapout() can transfer the page's memory+swap charge (PCG_MEMSW) to the swap entry before the final put_page() in page reclaim. Finally, page_cgroup changes are now protected by whatever protection the page itself offers: anonymous pages are charged under the page table lock, whereas page cache insertions, swapin, and migration hold the page lock. Uncharging happens under full exclusion with no outstanding references. Charging and uncharging also ensure that the page is off-LRU, which serializes against charge migration. Remove the very costly page_cgroup lock and set pc->flags non-atomically. [mhocko@suse.cz: mem_cgroup_charge_statistics needs preempt_disable] [vdavydov@parallels.com: fix flags definition] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Tested-by: Jet Chen <jet.chen@intel.com> Acked-by: Michal Hocko <mhocko@suse.cz> Tested-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The memcg uncharging code that is involved towards the end of a page's
lifetime - truncation, reclaim, swapout, migration - is impressively
complicated and fragile.

Because anonymous and file pages were always charged before they had their
page->mapping established, uncharges had to happen when the page type
could still be known from the context; as in unmap for anonymous, page
cache removal for file and shmem pages, and swap cache truncation for swap
pages.  However, these operations happen well before the page is actually
freed, and so a lot of synchronization is necessary:

- Charging, uncharging, page migration, and charge migration all need
  to take a per-page bit spinlock as they could race with uncharging.

- Swap cache truncation happens during both swap-in and swap-out, and
  possibly repeatedly before the page is actually freed.  This means
  that the memcg swapout code is called from many contexts that make
  no sense and it has to figure out the direction from page state to
  make sure memory and memory+swap are always correctly charged.

- On page migration, the old page might be unmapped but then reused,
  so memcg code has to prevent untimely uncharging in that case.
  Because this code - which should be a simple charge transfer - is so
  special-cased, it is not reusable for replace_page_cache().

But now that charged pages always have a page->mapping, introduce
mem_cgroup_uncharge(), which is called after the final put_page(), when we
know for sure that nobody is looking at the page anymore.

For page migration, introduce mem_cgroup_migrate(), which is called after
the migration is successful and the new page is fully rmapped.  Because
the old page is no longer uncharged after migration, prevent double
charges by decoupling the page's memcg association (PCG_USED and
pc->mem_cgroup) from the page holding an actual charge.  The new bits
PCG_MEM and PCG_MEMSW represent the respective charges and are transferred
to the new page during migration.

mem_cgroup_migrate() is suitable for replace_page_cache() as well,
which gets rid of mem_cgroup_replace_page_cache().  However, care
needs to be taken because both the source and the target page can
already be charged and on the LRU when fuse is splicing: grab the page
lock on the charge moving side to prevent changing pc->mem_cgroup of a
page under migration.  Also, the lruvecs of both pages change as we
uncharge the old and charge the new during migration, and putback may
race with us, so grab the lru lock and isolate the pages iff on LRU to
prevent races and ensure the pages are on the right lruvec afterward.

Swap accounting is massively simplified: because the page is no longer
uncharged as early as swap cache deletion, a new mem_cgroup_swapout() can
transfer the page's memory+swap charge (PCG_MEMSW) to the swap entry
before the final put_page() in page reclaim.

Finally, page_cgroup changes are now protected by whatever protection the
page itself offers: anonymous pages are charged under the page table lock,
whereas page cache insertions, swapin, and migration hold the page lock.
Uncharging happens under full exclusion with no outstanding references.
Charging and uncharging also ensure that the page is off-LRU, which
serializes against charge migration.  Remove the very costly page_cgroup
lock and set pc->flags non-atomically.

[mhocko@suse.cz: mem_cgroup_charge_statistics needs preempt_disable]
[vdavydov@parallels.com: fix flags definition]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Tested-by: Jet Chen <jet.chen@intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: memcontrol: rewrite charge API 2014-08-08T22:57:17+00:00 Johannes Weiner hannes@cmpxchg.org 2014-08-08T21:19:20+00:00 00501b531c4723972aa11d6d4ebcf8d6552007c8 These patches rework memcg charge lifetime to integrate more naturally with the lifetime of user pages. This drastically simplifies the code and reduces charging and uncharging overhead. The most expensive part of charging and uncharging is the page_cgroup bit spinlock, which is removed entirely after this series. Here are the top-10 profile entries of a stress test that reads a 128G sparse file on a freshly booted box, without even a dedicated cgroup (i.e. executing in the root memcg). Before: 15.36% cat [kernel.kallsyms] [k] copy_user_generic_string 13.31% cat [kernel.kallsyms] [k] memset 11.48% cat [kernel.kallsyms] [k] do_mpage_readpage 4.23% cat [kernel.kallsyms] [k] get_page_from_freelist 2.38% cat [kernel.kallsyms] [k] put_page 2.32% cat [kernel.kallsyms] [k] __mem_cgroup_commit_charge 2.18% kswapd0 [kernel.kallsyms] [k] __mem_cgroup_uncharge_common 1.92% kswapd0 [kernel.kallsyms] [k] shrink_page_list 1.86% cat [kernel.kallsyms] [k] __radix_tree_lookup 1.62% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn After: 15.67% cat [kernel.kallsyms] [k] copy_user_generic_string 13.48% cat [kernel.kallsyms] [k] memset 11.42% cat [kernel.kallsyms] [k] do_mpage_readpage 3.98% cat [kernel.kallsyms] [k] get_page_from_freelist 2.46% cat [kernel.kallsyms] [k] put_page 2.13% kswapd0 [kernel.kallsyms] [k] shrink_page_list 1.88% cat [kernel.kallsyms] [k] __radix_tree_lookup 1.67% cat [kernel.kallsyms] [k] __pagevec_lru_add_fn 1.39% kswapd0 [kernel.kallsyms] [k] free_pcppages_bulk 1.30% cat [kernel.kallsyms] [k] kfree As you can see, the memcg footprint has shrunk quite a bit. text data bss dec hex filename 37970 9892 400 48262 bc86 mm/memcontrol.o.old 35239 9892 400 45531 b1db mm/memcontrol.o This patch (of 4): The memcg charge API charges pages before they are rmapped - i.e. have an actual "type" - and so every callsite needs its own set of charge and uncharge functions to know what type is being operated on. Worse, uncharge has to happen from a context that is still type-specific, rather than at the end of the page's lifetime with exclusive access, and so requires a lot of synchronization. Rewrite the charge API to provide a generic set of try_charge(), commit_charge() and cancel_charge() transaction operations, much like what's currently done for swap-in: mem_cgroup_try_charge() attempts to reserve a charge, reclaiming pages from the memcg if necessary. mem_cgroup_commit_charge() commits the page to the charge once it has a valid page->mapping and PageAnon() reliably tells the type. mem_cgroup_cancel_charge() aborts the transaction. This reduces the charge API and enables subsequent patches to drastically simplify uncharging. As pages need to be committed after rmap is established but before they are added to the LRU, page_add_new_anon_rmap() must stop doing LRU additions again. Revive lru_cache_add_active_or_unevictable(). [hughd@google.com: fix shmem_unuse] [hughd@google.com: Add comments on the private use of -EAGAIN] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
These patches rework memcg charge lifetime to integrate more naturally
with the lifetime of user pages.  This drastically simplifies the code and
reduces charging and uncharging overhead.  The most expensive part of
charging and uncharging is the page_cgroup bit spinlock, which is removed
entirely after this series.

Here are the top-10 profile entries of a stress test that reads a 128G
sparse file on a freshly booted box, without even a dedicated cgroup (i.e.
 executing in the root memcg).  Before:

    15.36%              cat  [kernel.kallsyms]   [k] copy_user_generic_string
    13.31%              cat  [kernel.kallsyms]   [k] memset
    11.48%              cat  [kernel.kallsyms]   [k] do_mpage_readpage
     4.23%              cat  [kernel.kallsyms]   [k] get_page_from_freelist
     2.38%              cat  [kernel.kallsyms]   [k] put_page
     2.32%              cat  [kernel.kallsyms]   [k] __mem_cgroup_commit_charge
     2.18%          kswapd0  [kernel.kallsyms]   [k] __mem_cgroup_uncharge_common
     1.92%          kswapd0  [kernel.kallsyms]   [k] shrink_page_list
     1.86%              cat  [kernel.kallsyms]   [k] __radix_tree_lookup
     1.62%              cat  [kernel.kallsyms]   [k] __pagevec_lru_add_fn

After:

    15.67%           cat  [kernel.kallsyms]   [k] copy_user_generic_string
    13.48%           cat  [kernel.kallsyms]   [k] memset
    11.42%           cat  [kernel.kallsyms]   [k] do_mpage_readpage
     3.98%           cat  [kernel.kallsyms]   [k] get_page_from_freelist
     2.46%           cat  [kernel.kallsyms]   [k] put_page
     2.13%       kswapd0  [kernel.kallsyms]   [k] shrink_page_list
     1.88%           cat  [kernel.kallsyms]   [k] __radix_tree_lookup
     1.67%           cat  [kernel.kallsyms]   [k] __pagevec_lru_add_fn
     1.39%       kswapd0  [kernel.kallsyms]   [k] free_pcppages_bulk
     1.30%           cat  [kernel.kallsyms]   [k] kfree

As you can see, the memcg footprint has shrunk quite a bit.

   text    data     bss     dec     hex filename
  37970    9892     400   48262    bc86 mm/memcontrol.o.old
  35239    9892     400   45531    b1db mm/memcontrol.o

This patch (of 4):

The memcg charge API charges pages before they are rmapped - i.e.  have an
actual "type" - and so every callsite needs its own set of charge and
uncharge functions to know what type is being operated on.  Worse,
uncharge has to happen from a context that is still type-specific, rather
than at the end of the page's lifetime with exclusive access, and so
requires a lot of synchronization.

Rewrite the charge API to provide a generic set of try_charge(),
commit_charge() and cancel_charge() transaction operations, much like
what's currently done for swap-in:

  mem_cgroup_try_charge() attempts to reserve a charge, reclaiming
  pages from the memcg if necessary.

  mem_cgroup_commit_charge() commits the page to the charge once it
  has a valid page->mapping and PageAnon() reliably tells the type.

  mem_cgroup_cancel_charge() aborts the transaction.

This reduces the charge API and enables subsequent patches to
drastically simplify uncharging.

As pages need to be committed after rmap is established but before they
are added to the LRU, page_add_new_anon_rmap() must stop doing LRU
additions again.  Revive lru_cache_add_active_or_unevictable().

[hughd@google.com: fix shmem_unuse]
[hughd@google.com: Add comments on the private use of -EAGAIN]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: describe mmap_sem rules for __lock_page_or_retry() and callers 2014-08-07T01:01:20+00:00 Paul Cassella cassella@cray.com 2014-08-06T23:07:24+00:00 9a95f3cf7b33d66fa64727cff8cd2f2a9d09f335 Add a comment describing the circumstances in which __lock_page_or_retry() will or will not release the mmap_sem when returning 0. Add comments to lock_page_or_retry()'s callers (filemap_fault(), do_swap_page()) noting the impact on VM_FAULT_RETRY returns. Add comments on up the call tree, particularly replacing the false "We return with mmap_sem still held" comments. Signed-off-by: Paul Cassella <cassella@cray.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Add a comment describing the circumstances in which
__lock_page_or_retry() will or will not release the mmap_sem when
returning 0.

Add comments to lock_page_or_retry()'s callers (filemap_fault(),
do_swap_page()) noting the impact on VM_FAULT_RETRY returns.

Add comments on up the call tree, particularly replacing the false "We
return with mmap_sem still held" comments.

Signed-off-by: Paul Cassella <cassella@cray.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: replace init_page_accessed by __SetPageReferenced 2014-08-07T01:01:19+00:00 Hugh Dickins hughd@google.com 2014-08-06T23:06:43+00:00 eb39d618f9e80f81cfc5788cf1b252d141c2f0c3 Do we really need an exported alias for __SetPageReferenced()? Its callers better know what they're doing, in which case the page would not be already marked referenced. Kill init_page_accessed(), just __SetPageReferenced() inline. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Prabhakar Lad <prabhakar.csengg@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Do we really need an exported alias for __SetPageReferenced()? Its
callers better know what they're doing, in which case the page would not
be already marked referenced.  Kill init_page_accessed(), just
__SetPageReferenced() inline.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Prabhakar Lad <prabhakar.csengg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-08-04T23:23:30+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-08-04T23:23:30+00:00 98959948a7ba33cf8c708626e0d2a1456397e1c6 Pull scheduler updates from Ingo Molnar: - Move the nohz kick code out of the scheduler tick to a dedicated IPI, from Frederic Weisbecker. This necessiated quite some background infrastructure rework, including: * Clean up some irq-work internals * Implement remote irq-work * Implement nohz kick on top of remote irq-work * Move full dynticks timer enqueue notification to new kick * Move multi-task notification to new kick * Remove unecessary barriers on multi-task notification - Remove proliferation of wait_on_bit() action functions and allow wait_on_bit_action() functions to support a timeout. (Neil Brown) - Another round of sched/numa improvements, cleanups and fixes. (Rik van Riel) - Implement fast idling of CPUs when the system is partially loaded, for better scalability. (Tim Chen) - Restructure and fix the CPU hotplug handling code that may leave cfs_rq and rt_rq's throttled when tasks are migrated away from a dead cpu. (Kirill Tkhai) - Robustify the sched topology setup code. (Peterz Zijlstra) - Improve sched_feat() handling wrt. static_keys (Jason Baron) - Misc fixes. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) sched/fair: Fix 'make xmldocs' warning caused by missing description sched: Use macro for magic number of -1 for setparam sched: Robustify topology setup sched: Fix sched_setparam() policy == -1 logic sched: Allow wait_on_bit_action() functions to support a timeout sched: Remove proliferation of wait_on_bit() action functions sched/numa: Revert "Use effective_load() to balance NUMA loads" sched: Fix static_key race with sched_feat() sched: Remove extra static_key*() function indirection sched/rt: Fix replenish_dl_entity() comments to match the current upstream code sched: Transform resched_task() into resched_curr() sched/deadline: Kill task_struct->pi_top_task sched: Rework check_for_tasks() sched/rt: Enqueue just unthrottled rt_rq back on the stack in __disable_runtime() sched/fair: Disable runtime_enabled on dying rq sched/numa: Change scan period code to match intent sched/numa: Rework best node setting in task_numa_migrate() sched/numa: Examine a task move when examining a task swap sched/numa: Simplify task_numa_compare() sched/numa: Use effective_load() to balance NUMA loads ... 
Pull scheduler updates from Ingo Molnar:

 - Move the nohz kick code out of the scheduler tick to a dedicated IPI,
   from Frederic Weisbecker.

  This necessiated quite some background infrastructure rework,
  including:

   * Clean up some irq-work internals
   * Implement remote irq-work
   * Implement nohz kick on top of remote irq-work
   * Move full dynticks timer enqueue notification to new kick
   * Move multi-task notification to new kick
   * Remove unecessary barriers on multi-task notification

 - Remove proliferation of wait_on_bit() action functions and allow
   wait_on_bit_action() functions to support a timeout.  (Neil Brown)

 - Another round of sched/numa improvements, cleanups and fixes.  (Rik
   van Riel)

 - Implement fast idling of CPUs when the system is partially loaded,
   for better scalability.  (Tim Chen)

 - Restructure and fix the CPU hotplug handling code that may leave
   cfs_rq and rt_rq's throttled when tasks are migrated away from a dead
   cpu.  (Kirill Tkhai)

 - Robustify the sched topology setup code.  (Peterz Zijlstra)

 - Improve sched_feat() handling wrt.  static_keys (Jason Baron)

 - Misc fixes.

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits)
  sched/fair: Fix 'make xmldocs' warning caused by missing description
  sched: Use macro for magic number of -1 for setparam
  sched: Robustify topology setup
  sched: Fix sched_setparam() policy == -1 logic
  sched: Allow wait_on_bit_action() functions to support a timeout
  sched: Remove proliferation of wait_on_bit() action functions
  sched/numa: Revert "Use effective_load() to balance NUMA loads"
  sched: Fix static_key race with sched_feat()
  sched: Remove extra static_key*() function indirection
  sched/rt: Fix replenish_dl_entity() comments to match the current upstream code
  sched: Transform resched_task() into resched_curr()
  sched/deadline: Kill task_struct->pi_top_task
  sched: Rework check_for_tasks()
  sched/rt: Enqueue just unthrottled rt_rq back on the stack in __disable_runtime()
  sched/fair: Disable runtime_enabled on dying rq
  sched/numa: Change scan period code to match intent
  sched/numa: Rework best node setting in task_numa_migrate()
  sched/numa: Examine a task move when examining a task swap
  sched/numa: Simplify task_numa_compare()
  sched/numa: Use effective_load() to balance NUMA loads
  ...
mm: fix filemap.c pagecache_get_page() kernel-doc warnings 2014-07-31T00:16:13+00:00 Randy Dunlap rdunlap@infradead.org 2014-07-30T23:08:37+00:00 75325189c9e4df5f67eec5ec5b0d90759084887b Fix kernel-doc warnings in mm/filemap.c: pagecache_get_page(): Warning(..//mm/filemap.c:1054): No description found for parameter 'cache_gfp_mask' Warning(..//mm/filemap.c:1054): No description found for parameter 'radix_gfp_mask' Warning(..//mm/filemap.c:1054): Excess function parameter 'gfp_mask' description in 'pagecache_get_page' Fixes: 2457aec63745 ("mm: non-atomically mark page accessed during page cache allocation where possible") [mgorman@suse.de: change everything] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Fix kernel-doc warnings in mm/filemap.c: pagecache_get_page():

  Warning(..//mm/filemap.c:1054): No description found for parameter 'cache_gfp_mask'
  Warning(..//mm/filemap.c:1054): No description found for parameter 'radix_gfp_mask'
  Warning(..//mm/filemap.c:1054): Excess function parameter 'gfp_mask' description in 'pagecache_get_page'

Fixes: 2457aec63745 ("mm: non-atomically mark page accessed during page cache allocation where possible")

[mgorman@suse.de: change everything]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sched: Remove proliferation of wait_on_bit() action functions 2014-07-16T13:10:39+00:00 NeilBrown neilb@suse.de 2014-07-07T05:16:04+00:00 743162013d40ca612b4cb53d3a200dff2d9ab26e The current "wait_on_bit" interface requires an 'action' function to be provided which does the actual waiting. There are over 20 such functions, many of them identical. Most cases can be satisfied by one of just two functions, one which uses io_schedule() and one which just uses schedule(). So: Rename wait_on_bit and wait_on_bit_lock to wait_on_bit_action and wait_on_bit_lock_action to make it explicit that they need an action function. Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io which are *not* given an action function but implicitly use a standard one. The decision to error-out if a signal is pending is now made based on the 'mode' argument rather than being encoded in the action function. All instances of the old wait_on_bit and wait_on_bit_lock which can use the new version have been changed accordingly and their action functions have been discarded. wait_on_bit{_lock} does not return any specific error code in the event of a signal so the caller must check for non-zero and interpolate their own error code as appropriate. The wait_on_bit() call in __fscache_wait_on_invalidate() was ambiguous as it specified TASK_UNINTERRUPTIBLE but used fscache_wait_bit_interruptible as an action function. David Howells confirms this should be uniformly "uninterruptible" The main remaining user of wait_on_bit{,_lock}_action is NFS which needs to use a freezer-aware schedule() call. A comment in fs/gfs2/glock.c notes that having multiple 'action' functions is useful as they display differently in the 'wchan' field of 'ps'. (and /proc/$PID/wchan). As the new bit_wait{,_io} functions are tagged "__sched", they will not show up at all, but something higher in the stack. So the distinction will still be visible, only with different function names (gds2_glock_wait versus gfs2_glock_dq_wait in the gfs2/glock.c case). Since first version of this patch (against 3.15) two new action functions appeared, on in NFS and one in CIFS. CIFS also now uses an action function that makes the same freezer aware schedule call as NFS. Signed-off-by: NeilBrown <neilb@suse.de> Acked-by: David Howells <dhowells@redhat.com> (fscache, keys) Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2) Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Steve French <sfrench@samba.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown Signed-off-by: Ingo Molnar <mingo@kernel.org> 
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().

So:
 Rename wait_on_bit and        wait_on_bit_lock to
        wait_on_bit_action and wait_on_bit_lock_action
 to make it explicit that they need an action function.

 Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
 which are *not* given an action function but implicitly use
 a standard one.
 The decision to error-out if a signal is pending is now made
 based on the 'mode' argument rather than being encoded in the action
 function.

 All instances of the old wait_on_bit and wait_on_bit_lock which
 can use the new version have been changed accordingly and their
 action functions have been discarded.
 wait_on_bit{_lock} does not return any specific error code in the
 event of a signal so the caller must check for non-zero and
 interpolate their own error code as appropriate.

The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"

The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.

A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack.  So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).

Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS.  CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12T17:30:18+00:00 Linus Torvalds torvalds@linux-foundation.org 2014-06-12T17:30:18+00:00 16b9057804c02e2d351e9c8f606e909b43cbd9e7 Pull vfs updates from Al Viro: "This the bunch that sat in -next + lock_parent() fix. This is the minimal set; there's more pending stuff. In particular, I really hope to get acct.c fixes merged this cycle - we need that to deal sanely with delayed-mntput stuff. In the next pile, hopefully - that series is fairly short and localized (kernel/acct.c, fs/super.c and fs/namespace.c). In this pile: more iov_iter work. Most of prereqs for ->splice_write with sane locking order are there and Kent's dio rewrite would also fit nicely on top of this pile" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits) lock_parent: don't step on stale ->d_parent of all-but-freed one kill generic_file_splice_write() ceph: switch to iter_file_splice_write() shmem: switch to iter_file_splice_write() nfs: switch to iter_splice_write_file() fs/splice.c: remove unneeded exports ocfs2: switch to iter_file_splice_write() ->splice_write() via ->write_iter() bio_vec-backed iov_iter optimize copy_page_{to,from}_iter() bury generic_file_aio_{read,write} lustre: get rid of messing with iovecs ceph: switch to ->write_iter() ceph_sync_direct_write: stop poking into iov_iter guts ceph_sync_read: stop poking into iov_iter guts new helper: copy_page_from_iter() fuse: switch to ->write_iter() btrfs: switch to ->write_iter() ocfs2: switch to ->write_iter() xfs: switch to ->write_iter() ... 
Pull vfs updates from Al Viro:
 "This the bunch that sat in -next + lock_parent() fix.  This is the
  minimal set; there's more pending stuff.

  In particular, I really hope to get acct.c fixes merged this cycle -
  we need that to deal sanely with delayed-mntput stuff.  In the next
  pile, hopefully - that series is fairly short and localized
  (kernel/acct.c, fs/super.c and fs/namespace.c).  In this pile: more
  iov_iter work.  Most of prereqs for ->splice_write with sane locking
  order are there and Kent's dio rewrite would also fit nicely on top of
  this pile"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits)
  lock_parent: don't step on stale ->d_parent of all-but-freed one
  kill generic_file_splice_write()
  ceph: switch to iter_file_splice_write()
  shmem: switch to iter_file_splice_write()
  nfs: switch to iter_splice_write_file()
  fs/splice.c: remove unneeded exports
  ocfs2: switch to iter_file_splice_write()
  ->splice_write() via ->write_iter()
  bio_vec-backed iov_iter
  optimize copy_page_{to,from}_iter()
  bury generic_file_aio_{read,write}
  lustre: get rid of messing with iovecs
  ceph: switch to ->write_iter()
  ceph_sync_direct_write: stop poking into iov_iter guts
  ceph_sync_read: stop poking into iov_iter guts
  new helper: copy_page_from_iter()
  fuse: switch to ->write_iter()
  btrfs: switch to ->write_iter()
  ocfs2: switch to ->write_iter()
  xfs: switch to ->write_iter()
  ...