From 6b1ffd2fa340aca8687ec0d1795c0be19f72a29c Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 25 Jul 2011 17:11:57 -0700 Subject: [PATCH] mm/backing-dev.c: reset bdi min_ratio in bdi_unregister() [ upstream commit ccb6108f5b0b541d3eb332c3a73e645c0f84278e ] Vito said: : The system has many usb disks coming and going day to day, with their : respective bdi's having min_ratio set to 1 when inserted. It works for : some time until eventually min_ratio can no longer be set, even when the : active set of bdi's seen in /sys/class/bdi/*/min_ratio doesn't add up to : anywhere near 100. : : This then leads to an unrelated starvation problem caused by write-heavy : fuse mounts being used atop the usb disks, a problem the min_ratio setting : at the underlying devices bdi effectively prevents. Fix this leakage by resetting the bdi min_ratio when unregistering the BDI. Signed-off-by: Peter Zijlstra Reported-by: Vito Caputo Cc: Wu Fengguang Cc: Miklos Szeredi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Andi Kleen --- mm/backing-dev.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index c0f71571982..3f2b8d037c9 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -646,6 +646,7 @@ static void bdi_prune_sb(struct backing_dev_info *bdi) void bdi_unregister(struct backing_dev_info *bdi) { if (bdi->dev) { + bdi_set_min_ratio(bdi, 0); bdi_prune_sb(bdi); if (!bdi_cap_flush_forker(bdi)) -- 2.11.4.GIT