]> nv-tegra.nvidia Code Review - linux-2.6.git/commit
mm: optimize kill_bdev()
authorPeter Zijlstra <a.p.zijlstra@chello.nl>
Sun, 6 May 2007 21:49:55 +0000 (14:49 -0700)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>
Mon, 7 May 2007 19:12:55 +0000 (12:12 -0700)
commitf9a14399aea13830d8af6798a53207bb0a900945
treeb2501f1ce1d2a4564cd9a29c55705e524f594ad1
parentf98393a64ca1392130724c3acb4e3f325801d2b6
mm: optimize kill_bdev()

Remove duplicate work in kill_bdev().

It currently invalidates and then truncates the bdev's mapping.
invalidate_mapping_pages() will opportunistically remove pages from the
mapping.  And truncate_inode_pages() will forcefully remove all pages.

The only thing truncate doesn't do is flush the bh lrus.  So do that
explicitly.  This avoids (very unlikely) but possible invalid lookup
results if the same bdev is quickly re-issued.

It also will prevent extreme kernel latencies which are observed when
blockdevs which have a large amount of pagecache are unmounted, by avoiding
invalidate_mapping_pages() on that path.  invalidate_mapping_pages() has no
cond_resched (it can be called under spinlock), whereas truncate_inode_pages()
has one.

[akpm@linux-foundation.org: restore nrpages==0 optimisation]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/block_dev.c
fs/buffer.c
include/linux/buffer_head.h