diff options
author | Nick Piggin <npiggin@suse.de> | 2007-10-16 12:24:53 +0400 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-16 20:42:54 +0400 |
commit | 41cb8ac025dbbf6782eae10d231e7e2336ad3724 (patch) | |
tree | 0070e26ee574338a4a3f56f574e1c126a4357c8e /mm/filemap.c | |
parent | 902aaed0d983dfd459fcb2b678608d4584782200 (diff) | |
download | linux-41cb8ac025dbbf6782eae10d231e7e2336ad3724.tar.xz |
mm: revert KERNEL_DS buffered write optimisation
Revert the patch from Neil Brown to optimise NFSD writev handling.
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r-- | mm/filemap.c | 32 |
1 files changed, 13 insertions, 19 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 7989c44cb293..c504db18ac26 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1874,27 +1874,21 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, /* Limit the size of the copy to the caller's write size */ bytes = min(bytes, count); - /* We only need to worry about prefaulting when writes are from - * user-space. NFSd uses vfs_writev with several non-aligned - * segments in the vector, and limiting to one segment a time is - * a noticeable performance for re-write + /* + * Limit the size of the copy to that of the current segment, + * because fault_in_pages_readable() doesn't know how to walk + * segments. */ - if (!segment_eq(get_fs(), KERNEL_DS)) { - /* - * Limit the size of the copy to that of the current - * segment, because fault_in_pages_readable() doesn't - * know how to walk segments. - */ - bytes = min(bytes, cur_iov->iov_len - iov_base); + bytes = min(bytes, cur_iov->iov_len - iov_base); + + /* + * Bring in the user page that we will copy from _first_. + * Otherwise there's a nasty deadlock on copying from the + * same page as we're writing to, without it being marked + * up-to-date. + */ + fault_in_pages_readable(buf, bytes); - /* - * Bring in the user page that we will copy from - * _first_. Otherwise there's a nasty deadlock on - * copying from the same page as we're writing to, - * without it being marked up-to-date. - */ - fault_in_pages_readable(buf, bytes); - } page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec); if (!page) { status = -ENOMEM; |