Messages in this thread | | | Subject | Re: [PATCH] bcache: add separate workqueue for journal_write to avoid deadlock | From | Eddie Chapman <> | Date | Thu, 27 Sep 2018 16:53:06 +0100 |
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On 27/09/18 16:23, Coly Li wrote: > > On 9/27/18 9:45 PM, guoju wrote: >> After write SSD completed, bcache schedule journal_write work to >> system_wq, that is a public workqueue in system, without WQ_MEM_RECLAIM >> flag. system_wq is also a bound wq, and there may be no idle kworker on >> current processor. Creating a new kworker may unfortunately need to >> reclaim memory first, by shrinking cache and slab used by vfs, which >> depends on bcache device. That's a deadlock. >> >> This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM >> flag. It's rescuer thread will work to avoid the deadlock. >> >> Signed-off-by: guoju <fangguoju@gmail.com> > > Nice catch, this fix is quite important. I will try to submit to Jens ASAP. > > Thanks. > > Coly Li
Once this goes into 4.19, would this be a candidate for backporting to any stable kernels, or does it only fix something introduced in this cycle?
thanks, Eddie
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