* On Mon, Apr 18, 2011 at 10:02:04AM +1000, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
On Sun, Apr 17, 2011 at 09:53:08PM +0530, Raghavendra D Prabhu wrote:In the function bdi_wakeup_thread_delayed, no checks are performed on dirty_writeback_interval unlike other places and timeout is being set to zero as result, thus defeating the purpose. So, I have changed it to be passed default value of interval which is 500 centiseconds, when it is set to zero. I have also verified this and tested it.
Signed-off-by: Raghavendra D Prabhu <rprabhu@xxxxxxxxxxx> --- mm/backing-dev.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index befc875..d06533c 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -336,7 +336,10 @@ void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi) { unsigned long timeout; - timeout = msecs_to_jiffies(dirty_writeback_interval * 10); + if (dirty_writeback_interval) + timeout = msecs_to_jiffies(dirty_writeback_interval * 10); + else + timeout = msecs_to_jiffies(5000); mod_timer(&bdi->wb.wakeup_timer, jiffies + timeout); }Isn't the problem that the sysctl handler does not have a min/max valid value set? I.e. to prevent invalid values from being set in the first place? Cheers, Dave.
0 is a valid value for dirty_writeback_interval which according to the definition/documentation is disabled when set to 0. In other places, a constraint check is done on that value except here.
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