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authorJeff Layton <jlayton@redhat.com>2017-07-31 10:29:38 -0400
committerJeff Layton <jlayton@redhat.com>2017-08-01 08:39:29 -0400
commitffb959bbdf923b4f89a08a04aba2501b1b16d164 (patch)
treefa248b66c3b36982ee41ca1c51807b453b4d9e22 /include/linux/fs.h
parent3b49c9a1e984b524142afc7536041d8c66877113 (diff)
downloadlwn-ffb959bbdf923b4f89a08a04aba2501b1b16d164.tar.gz
lwn-ffb959bbdf923b4f89a08a04aba2501b1b16d164.zip
mm: remove optimizations based on i_size in mapping writeback waits
Marcelo added this i_size based optimization with a patch in 2004 (commitid is from the linux-history tree): commit 765dad09b4ac101a32d87af2bb793c3060497d3c Author: Marcelo Tosatti <marcelo.tosatti@cyclades.com> Date: Tue Sep 7 17:51:17 2004 -0700 small wait_on_page_writeback_range() optimization filemap_fdatawait() calls wait_on_page_writeback_range() with -1 as "end" parameter. This is not needed since we know the EOF from the inode. Use that instead. There may be races here, particularly with clustered or network filesystems. It also seems like a bit of a layering violation since we're operating on an address_space here, not an inode. Finally, it's also questionable whether this optimization really helps on workloads that we care about. Should we be optimizing for writeback vs. truncate races in a codepath where we expect to wait anyway? It doesn't seem worth the risk. Remove this optimization from the filemap_fdatawait codepaths. This means that filemap_fdatawait becomes a trivial wrapper around filemap_fdatawait_range. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@redhat.com>
Diffstat (limited to 'include/linux/fs.h')
-rw-r--r--include/linux/fs.h7
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h
index af592ca3d509..909210bd6366 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2538,10 +2538,15 @@ extern int invalidate_inode_pages2_range(struct address_space *mapping,
extern int write_inode_now(struct inode *, int);
extern int filemap_fdatawrite(struct address_space *);
extern int filemap_flush(struct address_space *);
-extern int filemap_fdatawait(struct address_space *);
extern int filemap_fdatawait_keep_errors(struct address_space *mapping);
extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
loff_t lend);
+
+static inline int filemap_fdatawait(struct address_space *mapping)
+{
+ return filemap_fdatawait_range(mapping, 0, LLONG_MAX);
+}
+
extern bool filemap_range_has_page(struct address_space *, loff_t lstart,
loff_t lend);
extern int __must_check file_fdatawait_range(struct file *file, loff_t lstart,