On 12/12/19 11:04 AM, Davidlohr Bueso wrote: > There have been deadlock reports[1, 2] where put_page is called > from softirq context and this causes trouble with the hugetlb_lock, > as well as potentially the subpool lock. > > For such an unlikely scenario, lets not add irq dancing overhead > to the lock+unlock operations, which could incur in expensive > instruction dependencies, particularly when considering hard-irq > safety. For example PUSHF+POPF on x86. > > Instead, just use a workqueue and do the free_huge_page() in regular > task context. > > [1] https://lore.kernel.org/lkml/20191211194615.18502-1-longman@xxxxxxxxxx/ > [2] https://lore.kernel.org/lkml/20180905112341.21355-1-aneesh.kumar@xxxxxxxxxxxxx/ > > Reported-by: Waiman Long <longman@xxxxxxxxxx> > Reported-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> > Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx> Thank you Davidlohr. The patch does seem fairly simple and straight forward. I need to brush up on my workqueue knowledge to provide a full review. Longman, Do you have a test to reproduce the issue? If so, can you try running with this patch. -- Mike Kravetz
