From: NeilBrown Date: Fri, 16 Feb 2007 09:28:38 +0000 (-0800) Subject: [PATCH] knfsd: stop NFSD writes from being broken into lots of little writes to files... X-Git-Tag: v2.6.21-rc1~99 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=29dbb3fc8020f025bc38b262ec494e19fd3eac02;p=pandora-kernel.git [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 Cc: Norman Weathers Cc: Vladimir V. Saveliev Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed