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authorAbhi Das <adas@redhat.com>2017-08-04 19:15:32 +0200
committerBob Peterson <rpeterso@redhat.com>2017-08-10 17:51:03 +0200
commitb066a4eebd4f5ea77f7e5c7d13104d38e1a1d4bf (patch)
treeb8f53940b11052f2cb444f21586063eed0c1f3e5 /fs/gfs2/log.c
parentgfs2: Clean up waiting on glocks (diff)
downloadlinux-b066a4eebd4f5ea77f7e5c7d13104d38e1a1d4bf.tar.xz
linux-b066a4eebd4f5ea77f7e5c7d13104d38e1a1d4bf.zip
gfs2: forcibly flush ail to relieve memory pressure
On systems with low memory, it is possible for gfs2 to infinitely loop in balance_dirty_pages() under heavy IO (creating sparse files). balance_dirty_pages() attempts to write out the dirty pages via gfs2_writepages() but none are found because these dirty pages are being used by the journaling code in the ail. Normally, the journal has an upper threshold which when hit triggers an automatic flush of the ail. But this threshold can be higher than the number of allowable dirty pages and result in the ail never being flushed. This patch forces an ail flush when gfs2_writepages() fails to write anything. This is a good indication that the ail might be holding some dirty pages. Signed-off-by: Abhi Das <adas@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Diffstat (limited to '')
-rw-r--r--fs/gfs2/log.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 9a624f694400..31585c2d22fe 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -898,6 +898,10 @@ static inline int gfs2_jrnl_flush_reqd(struct gfs2_sbd *sdp)
static inline int gfs2_ail_flush_reqd(struct gfs2_sbd *sdp)
{
unsigned int used_blocks = sdp->sd_jdesc->jd_blocks - atomic_read(&sdp->sd_log_blks_free);
+
+ if (test_and_clear_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags))
+ return 1;
+
return used_blocks + atomic_read(&sdp->sd_log_blks_needed) >=
atomic_read(&sdp->sd_log_thresh2);
}