Re: possible deadlock in __wake_up_common_lock
From: Tetsuo Handa
Date: Wed Jan 02 2019 - 20:28:52 EST
On 2019/01/03 3:19, Qian Cai wrote:
> On 1/2/19 1:06 PM, Mel Gorman wrote:
>> While I recognise there is no test case available, how often does this
>> trigger in syzbot as it would be nice to have some confirmation any
>> patch is really fixing the problem.
> I think I did manage to trigger this every time running a mmap() workload
> causing swapping and a low-memory situation .
wakeup_kswapd() is called because tlb_next_batch() is doing GFP_NOWAIT
allocation. But since tlb_next_batch() can tolerate allocation failure,
does below change in tlb_next_batch() help?
#define GFP_NOWAIT (__GFP_KSWAPD_RECLAIM)
- batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
+ batch = (void *)__get_free_pages(__GFP_NOWARN, 0);