[Cluster-devel] [PATCH] gfs2: forcibly flush ail to relieve memory pressure

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
| 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.
| 
| Resolves: rhbz#1389079
| Signed-off-by: Abhi Das <adas@redhat.com>
| ---
|  fs/gfs2/aops.c   | 14 +++++++++++++-
|  fs/gfs2/incore.h |  1 +
|  fs/gfs2/log.c    |  4 ++++
|  3 files changed, 18 insertions(+), 1 deletion(-)
Hi,

Looks good. This is now pushed to the for-next branch of the linux-gfs2 tree:
https://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2.git/commit/fs/gfs2?h=for-next&id=9513f7bd924e64b4a75bdb99f6d85027b799e1ba

Regards,

Bob Peterson
Red Hat File Systems