Messages in this thread | | | Date | Sun, 27 Sep 2009 01:34:58 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] bdi_sync_writeback should WB_SYNC_NONE first |
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On Fri, 25 Sep 2009 10:10:14 -0400 Chris Mason <chris.mason@oracle.com> wrote:
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index 8e1e5e1..27f8e0e 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -225,7 +225,7 @@ static void bdi_sync_writeback(struct backing_dev_info *bdi, > { > struct wb_writeback_args args = { > .sb = sb, > - .sync_mode = WB_SYNC_ALL, > + .sync_mode = WB_SYNC_NONE, > .nr_pages = LONG_MAX, > .range_cyclic = 0, > }; > @@ -236,6 +236,13 @@ static void bdi_sync_writeback(struct backing_dev_info *bdi, > > bdi_queue_work(bdi, &work); > bdi_wait_on_work_clear(&work); > + > + args.sync_mode = WB_SYNC_ALL; > + args.nr_pages = LONG_MAX; > + > + work.state = WS_USED | WS_ONSTACK; > + bdi_queue_work(bdi, &work); > + bdi_wait_on_work_clear(&work); > }
Those LONG_MAX's are a worry. What prevents a very long almost-livelock from occurring if userspace is concurrently dirtying pagecache at a high rate?
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