Re: [PATCH 14/14] mm: Account for WRITEBACK_TEMP inbalance_dirty_pages

From: Maxim Patlasov
Date: Wed Nov 21 2012 - 07:01:54 EST


Added linux-mm@ to cc:. The patch can stand on it's own.

> Make balance_dirty_pages start the throttling when the WRITEBACK_TEMP
> counter is high enough. This prevents us from having too many dirty
> pages on fuse, thus giving the userspace part of it a chance to write
> stuff properly.
>
> Note, that the existing balance logic is per-bdi, i.e. if the fuse
> user task gets stuck in the function this means, that it either
> writes to the mountpoint it serves (but it can deadlock even without
> the writeback) or it is writing to some _other_ dirty bdi and in the
> latter case someone else will free the memory for it.

Signed-off-by: Maxim V. Patlasov <MPatlasov@xxxxxxxxxxxxx>
Signed-off-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
---
mm/page-writeback.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 830893b..499a606 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1220,7 +1220,8 @@ static void balance_dirty_pages(struct address_space *mapping,
*/
nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS);
- nr_dirty = nr_reclaimable + global_page_state(NR_WRITEBACK);
+ nr_dirty = nr_reclaimable + global_page_state(NR_WRITEBACK) +
+ global_page_state(NR_WRITEBACK_TEMP);

global_dirty_limits(&background_thresh, &dirty_thresh);


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