linux/drivers/staging/pohmelfs
Nick Piggin 2a4419b5b2 fs: fs_struct rwlock to spinlock
fs: fs_struct rwlock to spinlock

struct fs_struct.lock is an rwlock with the read-side used to protect root and
pwd members while taking references to them. Taking a reference to a path
typically requires just 2 atomic ops, so the critical section is very small.
Parallel read-side operations would have cacheline contention on the lock, the
dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a
real parallelism increase.

Replace it with a spinlock to avoid one or two atomic operations in typical
path lookup fastpath.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-18 08:35:46 -04:00
..
Kconfig Staging: pohmelfs: fix kconfig dependencies 2009-04-03 14:53:36 -07:00
Makefile Staging: pohmelfs: kconfig/makefile and vfs changes. 2009-04-03 14:53:36 -07:00
config.c Staging: Use kmemdup 2010-05-17 16:31:15 -07:00
crypto.c Staging: pohmelfs: fix spaces and TAB coding style issue in crypto.c 2010-05-11 11:35:41 -07:00
dir.c Staging: pohmelfs: fix spaces and TAB coding style issue in dir.c 2010-05-11 11:35:41 -07:00
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2010-08-10 11:26:52 -07:00
lock.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
mcache.c Staging: pohmelfs: distributed locking and cache coherency protocol. 2009-04-03 14:53:34 -07:00
net.c Staging: pohmelfs: fix spaces and TAB coding style issue in net.c 2010-05-11 11:35:41 -07:00
netfs.h Staging: pohmelfs: fix spaces and TAB coding style issue in netfs.h 2010-05-11 11:35:41 -07:00
path_entry.c fs: fs_struct rwlock to spinlock 2010-08-18 08:35:46 -04:00
trans.c Staging: pohmelfs: sync with the development tree 2009-09-15 12:02:30 -07:00