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Groups > linux.kernel > #1363031
| From | Jens Axboe <axboe@fb.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC |
| Date | 2016-03-22 22:50 +0100 |
| Message-ID | <rfClA-23H-5@gated-at.bofh.it> (permalink) |
| References | <rfyKZ-88A-3@gated-at.bofh.it> <rfyL0-88A-31@gated-at.bofh.it> <rfCbU-20m-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 03/22/2016 03:34 PM, Dave Chinner wrote: > On Tue, Mar 22, 2016 at 11:55:16AM -0600, Jens Axboe wrote: >> If you call sync, the initial call to wakeup_flusher_threads() ends up >> calling wb_start_writeback() with reason=WB_REASON_SYNC, but >> wb_start_writeback() always uses WB_SYNC_NONE as the writeback mode. >> Ensure that we use WB_SYNC_ALL for a sync operation. > > This seems wrong to me. We want background write to happen as > quickly as possible and /not block/ when we first kick sync. It's not going to block. wakeup_flusher_threads() async queues writeback work through wb_start_writeback(). > The latter blocking passes of sync use WB_SYNC_ALL to ensure that we > block waiting for all remaining IO to be issued and waited on, but > the background writeback doesn't need to do this. That's fine, they can get to wait on the previously issued IO, which was properly submitted with WB_SYNC_ALL. Maybe I'm missing your point? -- Jens Axboe
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[PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC Jens Axboe <axboe@fb.com> - 2016-03-22 19:00 +0100
Re: [PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC Dave Chinner <david@fromorbit.com> - 2016-03-22 22:40 +0100
Re: [PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC Jens Axboe <axboe@fb.com> - 2016-03-22 22:50 +0100
Re: [PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC Jens Axboe <axboe@fb.com> - 2016-03-22 23:00 +0100
Re: [PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC Dave Chinner <david@fromorbit.com> - 2016-03-22 23:10 +0100
Re: [PATCH 2/6] writeback: wb_start_writeback() should use WB_SYNC_ALL for WB_REASON_SYNC Jens Axboe <axboe@fb.com> - 2016-03-22 23:10 +0100
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