diff options
author | NeilBrown <neilb@suse.de> | 2007-02-16 01:28:38 -0800 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-16 08:14:01 -0800 |
commit | 29dbb3fc8020f025bc38b262ec494e19fd3eac02 (patch) | |
tree | 579877f8d80e04e0908253b782b8e58c742b3fe6 /mm/memory.c | |
parent | 3160a711ef754758e7f85ae371cf900252c1a392 (diff) |
[PATCH] knfsd: stop NFSD writes from being broken into lots of little writes to filesystem
When NFSD receives a write request, the data is typically in a number of
1448 byte segments and writev is used to collect them together.
Unfortunately, generic_file_buffered_write passes these to the filesystem
one at a time, so an e.g. 32K over-write becomes a series of partial-page
writes to each page, causing the filesystem to have to pre-read those pages
- wasted effort.
generic_file_buffered_write handles one segment of the vector at a time as
it has to pre-fault in each segment to avoid deadlocks. When writing from
kernel-space (and nfsd does) this is not an issue, so
generic_file_buffered_write does not need to break and iovec from nfsd into
little pieces.
This patch avoids the splitting when get_fs is KERNEL_DS as it is
from NFSd.
This issue was introduced by commit 6527c2bdf1f833cc18e8f42bd97973d583e4aa83
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Norman Weathers <norman.r.weathers@conocophillips.com>
Cc: Vladimir V. Saveliev <vs@namesys.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
0 files changed, 0 insertions, 0 deletions