[RFC][PATCH 08/16] writeback: do not lose default bdi wake-ups
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From: Artem Bityutskiy on 16 Jul 2010 09:00 From: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> Currently the default bdi can lose wake ups. E.g., if 'bdi_queue_work()' is called when 'bdi_forker_thread()' is executing code after if (bdi_has_dirty_io(me->bdi)) wb_do_writeback(me, 0); but before 'set_current_state(TASK_INTERRUPTIBLE)'. This is unlikely, and the result is not very severe - we'll just delay the execution of the work, but this is still not very nice. This patch fixes the issue by checking whether the default bdi has works before the forker thread goes sleep. This patch also removes strange comment about a temporary measure, because there is nothing temporary there - many FSes use default bdi. Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy(a)nokia.com> --- mm/backing-dev.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 14fe1bb..ab783b9 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -335,10 +335,6 @@ static int bdi_forker_thread(void *ptr) struct backing_dev_info *bdi, *tmp; struct task_struct *task; - /* - * Temporary measure, we want to make sure we don't see - * dirty data on the default backing_dev_info - */ if (bdi_has_dirty_io(me->bdi)) wb_do_writeback(me, 0); @@ -358,6 +354,10 @@ static int bdi_forker_thread(void *ptr) bdi_add_default_flusher_thread(bdi); } + /* Keep working if default bdi still has some works */ + if (!list_empty(&me->bdi->work_list)) + __set_current_state(TASK_RUNNING); + if (list_empty(&bdi_pending_list)) { unsigned long wait; -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |