]> git.baikalelectronics.ru Git - kernel.git/commit
[XFS] remove old vmap cache
authorNick Piggin <npiggin@suse.de>
Tue, 6 Jan 2009 03:40:44 +0000 (14:40 +1100)
committerLachlan McIlroy <lachlan@redback.melbourne.sgi.com>
Tue, 6 Jan 2009 03:40:44 +0000 (14:40 +1100)
commit05bc52a2341b62edfaacd3e18d4e802016292d09
tree24f5f4ba78bf3722609e20a9346976226b95878a
parente2931d156cf78c22fe9bec012d0ce970695de685
[XFS] remove old vmap cache

XFS's vmap batching simply defers a number (up to 64) of vunmaps, and keeps
track of them in a list. To purge the batch, it just goes through the list and
calls vunamp on each one. This is pretty poor: a global TLB flush is generally
still performed on each vunmap, with the most expensive parts of the operation
being the broadcast IPIs and locking involved in the SMP callouts, and the
locking involved in the vmap management -- none of these are avoided by just
batching up the calls. I'm actually surprised it ever made much difference.
(Now that the lazy vmap allocator is upstream, this description is not quite
right, but the vunmap batching still doesn't seem to do much)

Rip all this logic out of XFS completely. I will improve vmap performance
and scalability directly in subsequent patch.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
fs/xfs/linux-2.6/xfs_buf.c