linux-stable.git/mm/percpu.c, branch v3.17.2

percpu: free percpu allocation info for uniprocessor system

2014-08-16T12:59:02+00:00

Currently, only SMP system free the percpu allocation info.
Uniprocessor system should free it too. For example, one x86 UML
virtual machine with 256MB memory, UML kernel wastes one page memory.

Signed-off-by: Honggang Li 
Signed-off-by: Tejun Heo 
Cc: stable@vger.kernel.org

percpu: Use ALIGN macro instead of hand coding alignment calculation

2014-06-19T15:00:27+00:00

Signed-off-by: Christoph Lameter 
Signed-off-by: Tejun Heo

percpu: make pcpu_alloc_chunk() use pcpu_mem_free() instead of kfree()

2014-04-14T20:18:06+00:00

pcpu_chunk_struct_size = sizeof(struct pcpu_chunk) +
	BITS_TO_LONGS(pcpu_unit_pages) * sizeof(unsigned long)

It hardly could be ever bigger than PAGE_SIZE even for large-scale machine,
but for consistency with its couterpart pcpu_mem_zalloc(),
use pcpu_mem_free() instead.

Commit b4916cb17c26 ("percpu: make pcpu_free_chunk() use
pcpu_mem_free() instead of kfree()") addressed this problem, but
missed this one.

tj: commit message updated

Signed-off-by: Jianyu Zhan 
Signed-off-by: Tejun Heo 
Fixes: 099a19d91ca4 ("percpu: allow limited allocation before slab is online)
Cc: stable@vger.kernel.org

percpu: renew the max_contig if we merge the head and previous block

2014-03-29T13:29:42+00:00

During pcpu_alloc_area(), we might merge the current head with the
previous block. Since we have calculated the max_contig using the
size of previous block before we skip it, and now we update the size
of previous block, so we should renew the max_contig.

Signed-off-by: Jianyu Zhan 
Signed-off-by: Tejun Heo

percpu: allocation size should be even

2014-03-17T20:10:29+00:00

723ad1d90b56 ("percpu: store offsets instead of lengths in ->map[]")
updated percpu area allocator to use the lowest bit, instead of sign,
to signify whether the area is occupied and forced min align to 2;
unfortunately, it forgot to force the allocation size to be even
causing malfunctions for the very rare odd-sized allocations.

Always force the allocations to be even sized.

tj: Wrote patch description.

Original-patch-by: Al Viro 
Signed-off-by: Tejun Heo

percpu: speed alloc_pcpu_area() up

2014-03-07T12:52:26+00:00

If we know that first N areas are all in use, we can obviously skip
them when searching for a free one.  And that kind of hint is very
easy to maintain.

Signed-off-by: Al Viro 
Signed-off-by: Tejun Heo

percpu: store offsets instead of lengths in ->map[]

2014-03-07T12:52:26+00:00

Current code keeps +-length for each area in chunk->map[].  It has
several unpleasant consequences:
	* even if we know that first 50 areas are all in use, allocation
still needs to go through all those areas just to sum their sizes, just
to get the offset of free one.
	* freeing needs to find the array entry refering to the area
in question; again, the need to sum the sizes until we reach the offset
we are interested in.  Note that offsets are monotonous, so simple
binary search would do here.

	New data representation: array of  pairs.
Each pair is represented by one int - we use offset|1 for 
and offset for  (we make sure that all offsets are even).
In the end we put a sentry entry - .  The first
entry is <0, flag>; it would be possible to store together the flag
for Nth area and offset for N+1st, but that leads to much hairier code.

In other words, where the old variant would have
	4, -8, -4, 4, -12, 100
(4 bytes free, 8 in use, 4 in use, 4 free, 12 in use, 100 free) we store
	<0,0>, <4,1>, <12,1>, <16,0>, <20,1>, <32,0>, <132,1>
i.e.
	0, 5, 13, 16, 21, 32, 133

This commit switches to new data representation and takes care of a couple
of low-hanging fruits in free_pcpu_area() - one is the switch to binary
search, another is not doing two memmove() when one would do.  Speeding
the alloc side up (by keeping track of how many areas in the beginning are
known to be all in use) also becomes possible - that'll be done in the next
commit.

Signed-off-by: Al Viro 
Signed-off-by: Tejun Heo

perpcu: fold pcpu_split_block() into the only caller

2014-03-07T12:52:26+00:00

... and simplify the results a bit.  Makes the next step easier
to deal with - we will be changing the data representation for
chunk->map[] and it's easier to do if the code in question is
not split between pcpu_alloc_area() and pcpu_split_block().

Signed-off-by: Al Viro 
Signed-off-by: Tejun Heo

Merge branch 'akpm' (incoming from Andrew)

2014-01-22T03:05:45+00:00

Merge first patch-bomb from Andrew Morton:

 - a couple of misc things

 - inotify/fsnotify work from Jan

 - ocfs2 updates (partial)

 - about half of MM

* emailed patches from Andrew Morton : (117 commits)
  mm/migrate: remove unused function, fail_migrate_page()
  mm/migrate: remove putback_lru_pages, fix comment on putback_movable_pages
  mm/migrate: correct failure handling if !hugepage_migration_support()
  mm/migrate: add comment about permanent failure path
  mm, page_alloc: warn for non-blockable __GFP_NOFAIL allocation failure
  mm: compaction: reset scanner positions immediately when they meet
  mm: compaction: do not mark unmovable pageblocks as skipped in async compaction
  mm: compaction: detect when scanners meet in isolate_freepages
  mm: compaction: reset cached scanner pfn's before reading them
  mm: compaction: encapsulate defer reset logic
  mm: compaction: trace compaction begin and end
  memcg, oom: lock mem_cgroup_print_oom_info
  sched: add tracepoints related to NUMA task migration
  mm: numa: do not automatically migrate KSM pages
  mm: numa: trace tasks that fail migration due to rate limiting
  mm: numa: limit scope of lock for NUMA migrate rate limiting
  mm: numa: make NUMA-migrate related functions static
  lib/show_mem.c: show num_poisoned_pages when oom
  mm/hwpoison: add '#' to hwpoison_inject
  mm/memblock: use WARN_ONCE when MAX_NUMNODES passed as input parameter
  ...

mm/percpu.c: use memblock apis for early memory allocations

2014-01-22T00:19:47+00:00

Switch to memblock interfaces for early memory allocator instead of
bootmem allocator.  No functional change in beahvior than what it is in
current code from bootmem users points of view.

Archs already converted to NO_BOOTMEM now directly use memblock
interfaces instead of bootmem wrappers build on top of memblock.  And
the archs which still uses bootmem, these new apis just fallback to
exiting bootmem APIs.

Signed-off-by: Santosh Shilimkar 
Cc: "Rafael J. Wysocki" 
Cc: Arnd Bergmann 
Cc: Christoph Lameter 
Cc: Greg Kroah-Hartman 
Cc: Grygorii Strashko 
Cc: H. Peter Anvin 
Cc: Johannes Weiner 
Cc: KAMEZAWA Hiroyuki 
Cc: Konrad Rzeszutek Wilk 
Cc: Michal Hocko 
Cc: Paul Walmsley 
Cc: Pavel Machek 
Cc: Russell King 
Cc: Tejun Heo 
Cc: Tony Lindgren 
Cc: Yinghai Lu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds