From 0d19bf0cb60fa5b274eb1ab488c4b0c3e02ccb8a Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 25 Jul 2011 17:11:57 -0700 Subject: mm/backing-dev.c: reset bdi min_ratio in bdi_unregister() commit ccb6108f5b0b541d3eb332c3a73e645c0f84278e upstream. 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman Change-Id: Iac6bcdd20e8656bc227eddb283aca3f8efd9fd1e Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/35646 Tested-by: Per VAHLNE Reviewed-by: Jonas ABERG --- mm/backing-dev.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index f032e6e1e09..e56fe35cef0 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -606,6 +606,7 @@ 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); trace_writeback_bdi_unregister(bdi); bdi_prune_sb(bdi); del_timer_sync(&bdi->wb.wakeup_timer); -- cgit v1.2.3