linux.git/drivers/staging/android/ashmem.c, branch v3.19

Merge branch 'for-3.19' of git://linux-nfs.org/~bfields/linux

2014-12-16T23:25:31+00:00

Pull nfsd updates from Bruce Fields:
 "A comparatively quieter cycle for nfsd this time, but still with two
  larger changes:

   - RPC server scalability improvements from Jeff Layton (using RCU
     instead of a spinlock to find idle threads).

   - server-side NFSv4.2 ALLOCATE/DEALLOCATE support from Anna
     Schumaker, enabling fallocate on new clients"

* 'for-3.19' of git://linux-nfs.org/~bfields/linux: (32 commits)
  nfsd4: fix xdr4 count of server in fs_location4
  nfsd4: fix xdr4 inclusion of escaped char
  sunrpc/cache: convert to use string_escape_str()
  sunrpc: only call test_bit once in svc_xprt_received
  fs: nfsd: Fix signedness bug in compare_blob
  sunrpc: add some tracepoints around enqueue and dequeue of svc_xprt
  sunrpc: convert to lockless lookup of queued server threads
  sunrpc: fix potential races in pool_stats collection
  sunrpc: add a rcu_head to svc_rqst and use kfree_rcu to free it
  sunrpc: require svc_create callers to pass in meaningful shutdown routine
  sunrpc: have svc_wake_up only deal with pool 0
  sunrpc: convert sp_task_pending flag to use atomic bitops
  sunrpc: move rq_cachetype field to better optimize space
  sunrpc: move rq_splice_ok flag into rq_flags
  sunrpc: move rq_dropme flag into rq_flags
  sunrpc: move rq_usedeferral flag to rq_flags
  sunrpc: move rq_local field to rq_flags
  sunrpc: add a generic rq_flags field to svc_rqst and move rq_secure to it
  nfsd: minor off by one checks in __write_versions()
  sunrpc: release svc_pool_map reference when serv allocation fails
  ...

mm: vmscan: invoke slab shrinkers from shrink_zone()

2014-12-13T20:42:48+00:00

The slab shrinkers are currently invoked from the zonelist walkers in
kswapd, direct reclaim, and zone reclaim, all of which roughly gauge the
eligible LRU pages and assemble a nodemask to pass to NUMA-aware
shrinkers, which then again have to walk over the nodemask.  This is
redundant code, extra runtime work, and fairly inaccurate when it comes to
the estimation of actually scannable LRU pages.  The code duplication will
only get worse when making the shrinkers cgroup-aware and requiring them
to have out-of-band cgroup hierarchy walks as well.

Instead, invoke the shrinkers from shrink_zone(), which is where all
reclaimers end up, to avoid this duplication.

Take the count for eligible LRU pages out of get_scan_count(), which
considers many more factors than just the availability of swap space, like
zone_reclaimable_pages() currently does.  Accumulate the number over all
visited lruvecs to get the per-zone value.

Some nodes have multiple zones due to memory addressing restrictions.  To
avoid putting too much pressure on the shrinkers, only invoke them once
for each such node, using the class zone of the allocation as the pivot
zone.

For now, this integrates the slab shrinking better into the reclaim logic
and gets rid of duplicative invocations from kswapd, direct reclaim, and
zone reclaim.  It also prepares for cgroup-awareness, allowing
memcg-capable shrinkers to be added at the lruvec level without much
duplication of both code and runtime work.

This changes kswapd behavior, which used to invoke the shrinkers for each
zone, but with scan ratios gathered from the entire node, resulting in
meaningless pressure quantities on multi-zone nodes.

Zone reclaim behavior also changes.  It used to shrink slabs until the
same amount of pages were shrunk as were reclaimed from the LRUs.  Now it
merely invokes the shrinkers once with the zone's scan ratio, which makes
the shrinkers go easier on caches that implement aging and would prefer
feeding back pressure from recently used slab objects to unused LRU pages.

[vdavydov@parallels.com: assure class zone is populated]
Signed-off-by: Johannes Weiner 
Cc: Dave Chinner 
Signed-off-by: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

VFS: Rename do_fallocate() to vfs_fallocate()

2014-11-07T21:17:44+00:00

This function needs to be exported so it can be used by the NFSD module
when responding to the new ALLOCATE and DEALLOCATE operations in NFS
v4.2.  Christoph Hellwig suggested renaming the function to stay
consistent with how other vfs functions are named.

Signed-off-by: Anna Schumaker 
Signed-off-by: J. Bruce Fields

ashmem: use vfs_llseek()

2014-10-09T06:39:04+00:00

Signed-off-by: Al Viro

staging: ashmem: Avoid deadlock between read and mmap calls

2014-02-07T17:03:16+00:00

Avoid holding ashmem_mutex across code that can page fault.  Page faults
grab the mmap_sem for the process, which are also held by mmap calls
prior to calling ashmem_mmap, which locks ashmem_mutex.  The reversed
order of locking between the two can deadlock.

The calls that can page fault are read() and the ASHMEM_SET_NAME and
ASHMEM_GET_NAME ioctls.  Move the code that accesses userspace pages
outside the ashmem_mutex.

Cc: Colin Cross 
Cc: Android Kernel Team 
Signed-off-by: Todd Poynor 
[jstultz: minor commit message tweaks]
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

staging: ashmem: Fix ASHMEM_PURGE_ALL_CACHES return value

2013-10-25T05:22:39+00:00

Hopefully this isn't too late for 3.12.

In commit 7dc19d5aff (convert shrinkers to new count/scan API)
the return value to PURGE_ALL_CACHES was dropped, causing -EPERM
to always be returned.

This patch re-adds the ret assignment, setting it to the the
ashmem_shrink_count(), which is the lru_count.

(Sorry this was missed in the review!)

Fixes: 7dc19d5affd7 ("convert shrinkers to new count/scan API")
Cc: Colin Cross 
Cc: Android Kernel Team 
Cc: Glauber Costa 
Reported-by: YongQin Liu 
Signed-off-by: John Stultz 
Cc: stable  # 3.12
Acked-by: Dave Chinner 
Signed-off-by: Greg Kroah-Hartman

staging/android: Add some more kerneldoc to ashmem.c

2013-09-17T14:47:40+00:00

I am sorry if I have interpreted anything incorrectly here. This is my
second day really attempting to understand the Ashmem system.

I can not finish documenting this class at this stage - There is still
more that I have to learn. For now, however, it will have to do.

Signed-off-by: Cruz Julian Bishop 
Signed-off-by: Greg Kroah-Hartman

staging/android: Initial partial kernel-doc for ashmem.c

2013-09-17T14:47:40+00:00

I am beginning to understand the core concepts at play here.

I am nowhere near finished with this class - However, it is better if
I commit what I have documented so far tonight - That way, if I mess
up tomorrow morning, I can just roll back to here.

Sorry if this clutters things up. In the end, once *everything* is
documented, it will make understanding the Android staging driver
easier to understand as a programmer - Hopefully for both new developers
and current ones.

Signed-off-by: Cruz Julian Bishop 
Signed-off-by: Greg Kroah-Hartman

drivers: convert shrinkers to new count/scan API

2013-09-10T22:56:32+00:00

Convert the driver shrinkers to the new API.  Most changes are compile
tested only because I either don't have the hardware or it's staging
stuff.

FWIW, the md and android code is pretty good, but the rest of it makes me
want to claw my eyes out.  The amount of broken code I just encountered is
mind boggling.  I've added comments explaining what is broken, but I fear
that some of the code would be best dealt with by being dragged behind the
bike shed, burying in mud up to it's neck and then run over repeatedly
with a blunt lawn mower.

Special mention goes to the zcache/zcache2 drivers.  They can't co-exist
in the build at the same time, they are under different menu options in
menuconfig, they only show up when you've got the right set of mm
subsystem options configured and so even compile testing is an exercise in
pulling teeth.  And that doesn't even take into account the horrible,
broken code...

[glommer@openvz.org: fixes for i915, android lowmem, zcache, bcache]
Signed-off-by: Dave Chinner 
Signed-off-by: Glauber Costa 
Acked-by: Mel Gorman 
Cc: Daniel Vetter 
Cc: Kent Overstreet 
Cc: John Stultz 
Cc: David Rientjes 
Cc: Jerome Glisse 
Cc: Thomas Hellstrom 
Cc: "Theodore Ts'o" 
Cc: Adrian Hunter 
Cc: Al Viro 
Cc: Artem Bityutskiy 
Cc: Arve Hjønnevåg 
Cc: Carlos Maiolino 
Cc: Christoph Hellwig 
Cc: Chuck Lever 
Cc: Daniel Vetter 
Cc: David Rientjes 
Cc: Gleb Natapov 
Cc: Greg Thelen 
Cc: J. Bruce Fields 
Cc: Jan Kara 
Cc: Jerome Glisse 
Cc: John Stultz 
Cc: KAMEZAWA Hiroyuki 
Cc: Kent Overstreet 
Cc: Kirill A. Shutemov 
Cc: Marcelo Tosatti 
Cc: Mel Gorman 
Cc: Steven Whitehouse 
Cc: Thomas Hellstrom 
Cc: Trond Myklebust 
Signed-off-by: Andrew Morton 

Signed-off-by: Al Viro

shrinker: add node awareness

2013-09-10T22:56:31+00:00

Pass the node of the current zone being reclaimed to shrink_slab(),
allowing the shrinker control nodemask to be set appropriately for node
aware shrinkers.

Signed-off-by: Dave Chinner 
Signed-off-by: Glauber Costa 
Acked-by: Mel Gorman 
Cc: "Theodore Ts'o" 
Cc: Adrian Hunter 
Cc: Al Viro 
Cc: Artem Bityutskiy 
Cc: Arve Hjønnevåg 
Cc: Carlos Maiolino 
Cc: Christoph Hellwig 
Cc: Chuck Lever 
Cc: Daniel Vetter 
Cc: David Rientjes 
Cc: Gleb Natapov 
Cc: Greg Thelen 
Cc: J. Bruce Fields 
Cc: Jan Kara 
Cc: Jerome Glisse 
Cc: John Stultz 
Cc: KAMEZAWA Hiroyuki 
Cc: Kent Overstreet 
Cc: Kirill A. Shutemov 
Cc: Marcelo Tosatti 
Cc: Mel Gorman 
Cc: Steven Whitehouse 
Cc: Thomas Hellstrom 
Cc: Trond Myklebust 
Signed-off-by: Andrew Morton 
Signed-off-by: Al Viro