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authorBrian Foster <bfoster@redhat.com>2021-01-22 16:48:20 -0800
committerDarrick J. Wong <djwong@kernel.org>2021-01-22 16:54:50 -0800
commit8321ddb2fa2964bffbc61400894a47dc3462323f (patch)
treeb8c273d96ec1173ee79e54ac242d162f20dc691e /fs/xfs/xfs_buf.h
parent10fb9ac1251fd0daa645c9e6a22270bfc72bd5e8 (diff)
xfs: don't drain buffer lru on freeze and read-only remount
xfs_buftarg_drain() is called from xfs_log_quiesce() to ensure the buffer cache is reclaimed during unmount. xfs_log_quiesce() is also called from xfs_quiesce_attr(), however, which means that cache state is completely drained for filesystem freeze and read-only remount. While technically harmless, this is unnecessarily heavyweight. Both freeze and read-only mounts allow reads and thus allow population of the buffer cache. Therefore, the transitional sequence in either case really only needs to quiesce outstanding writes to return the filesystem in a generally read-only state. Additionally, some users have reported that attempts to freeze a filesystem concurrent with a read-heavy workload causes the freeze process to stall for a significant amount of time. This occurs because, as mentioned above, the read workload repopulates the buffer LRU while the freeze task attempts to drain it. To improve this situation, replace the drain in xfs_log_quiesce() with a buffer I/O quiesce and lift the drain into the unmount path. This removes buffer LRU reclaim from freeze and read-only [re]mount, but ensures the LRU is still drained before the filesystem unmounts. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Diffstat (limited to 'fs/xfs/xfs_buf.h')
-rw-r--r--fs/xfs/xfs_buf.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index d5e31ba205e0..459ca34f26f5 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -347,6 +347,7 @@ xfs_buf_update_cksum(struct xfs_buf *bp, unsigned long cksum_offset)
extern struct xfs_buftarg *xfs_alloc_buftarg(struct xfs_mount *,
struct block_device *, struct dax_device *);
extern void xfs_free_buftarg(struct xfs_buftarg *);
+extern void xfs_buftarg_wait(struct xfs_buftarg *);
extern void xfs_buftarg_drain(struct xfs_buftarg *);
extern int xfs_setsize_buftarg(struct xfs_buftarg *, unsigned int);