linux-toradex.git/fs/mbcache.c, branch v4.6-rc6

mbcache: add reusable flag to cache entries

2016-02-23T03:44:04+00:00

To reduce amount of damage caused by single bad block, we limit number
of inodes sharing an xattr block to 1024. Thus there can be more xattr
blocks with the same contents when there are lots of files with the same
extended attributes. These xattr blocks naturally result in hash
collisions and can form long hash chains and we unnecessarily check each
such block only to find out we cannot use it because it is already
shared by too many inodes.

Add a reusable flag to cache entries which is cleared when a cache entry
has reached its maximum refcount.  Cache entries which are not marked
reusable are skipped by mb_cache_entry_find_{first,next}. This
significantly speeds up mbcache when there are many same xattr blocks.
For example for xattr-bench with 5 values and each process handling
20000 files, the run for 64 processes is 25x faster with this patch.
Even for 8 processes the speedup is almost 3x. We have also verified
that for situations where there is only one xattr block of each kind,
the patch doesn't have a measurable cost.

[JK: Remove handling of setting the same value since it is not needed
anymore, check for races in e_reusable setting, improve changelog,
add measurements]

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o

mbcache: get rid of _e_hash_list_head

2016-02-23T03:42:05+00:00

Get rid of field _e_hash_list_head in cache entries and add bit field
e_referenced instead.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o

mbcache2: rename to mbcache

2016-02-23T03:35:22+00:00

Since old mbcache code is gone, let's rename new code to mbcache since
number 2 is now meaningless. This is just a mechanical replacement.

Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o

mbcache: remove mbcache

2016-02-22T17:21:14+00:00

Both ext2 and ext4 are now converted to mbcache2. Remove the old mbcache
code.

Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o

fs/mbcache: replace __builtin_log2() with ilog2()

2014-06-26T02:08:29+00:00

Fix compiler error with some gcc version(s) that do not
support __builtin_log2() by replacing __builtin_log2() with
ilog2().

Signed-off-by: T. Makphaibulchoke 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Maciej W. Rozycki

ext4: each filesystem creates and uses its own mb_cache

2014-03-18T23:24:49+00:00

This patch adds new interfaces to create and destory cache,
ext4_xattr_create_cache() and ext4_xattr_destroy_cache(), and remove
the cache creation and destory calls from ex4_init_xattr() and
ext4_exitxattr() in fs/ext4/xattr.c.

fs/ext4/super.c has been changed so that when a filesystem is mounted
a cache is allocated and attched to its ext4_sb_info structure.

fs/mbcache.c has been changed so that only one slab allocator is
allocated and used by all mbcache structures.

Signed-off-by: T. Makphaibulchoke

fs/mbcache.c: doucple the locking of local from global data

2014-03-18T23:23:20+00:00

The patch increases the parallelism of mbcache by using the built-in
lock in the hlist_bl_node to protect the mb_cache's local block and
index hash chains.  The global data mb_cache_lru_list and
mb_cache_list continue to be protected by the global
mb_cache_spinlock.

New block group spinlock, mb_cache_bg_lock is also added to serialize
accesses to mb_cache_entry's local data.

A new member e_refcnt is added to the mb_cache_entry structure to help
preventing an mb_cache_entry from being deallocated by a free while it
is being referenced by either mb_cache_entry_get() or
mb_cache_entry_find().

Signed-off-by: T. Makphaibulchoke 
Signed-off-by: "Theodore Ts'o"

fs/mbcache.c: change block and index hash chain to hlist_bl_node

2014-03-18T23:19:41+00:00

This patch changes each mb_cache's both block and index hash chains to
use a hlist_bl_node, which contains a built-in lock.  This is the
first step in decoupling of locks serializing accesses to mb_cache
global data and each mb_cache_entry local data.

Signed-off-by: T. Makphaibulchoke 
Signed-off-by: "Theodore Ts'o"

fs: convert fs shrinkers to new scan/count API

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

Convert the filesystem shrinkers to use the new API, and standardise some
of the behaviours of the shrinkers at the same time.  For example,
nr_to_scan means the number of objects to scan, not the number of objects
to free.

I refactored the CIFS idmap shrinker a little - it really needs to be
broken up into a shrinker per tree and keep an item count with the tree
root so that we don't need to walk the tree every time the shrinker needs
to count the number of objects in the tree (i.e.  all the time under
memory pressure).

[glommer@openvz.org: fixes for ext4, ubifs, nfs, cifs and glock. Fixes are needed mainly due to new code merged in the tree]
[assorted fixes folded in]
Signed-off-by: Dave Chinner 
Signed-off-by: Glauber Costa 
Acked-by: Mel Gorman 
Acked-by: Artem Bityutskiy 
Acked-by: Jan Kara 
Acked-by: Steven Whitehouse 
Cc: Adrian Hunter 
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

super: fix calculation of shrinkable objects for small numbers

2013-09-10T22:56:29+00:00

The sysctl knob sysctl_vfs_cache_pressure is used to determine which
percentage of the shrinkable objects in our cache we should actively try
to shrink.

It works great in situations in which we have many objects (at least more
than 100), because the aproximation errors will be negligible.  But if
this is not the case, specially when total_objects < 100, we may end up
concluding that we have no objects at all (total / 100 = 0, if total <
100).

This is certainly not the biggest killer in the world, but may matter in
very low kernel memory situations.

Signed-off-by: Glauber Costa 
Reviewed-by: Carlos Maiolino 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Mel Gorman 
Cc: Dave Chinner 
Cc: Al Viro 
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