linux-kernel - Re: [PATCH 7/7] mm/page_alloc: Replace local

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Date:   Fri, 17 Jun 2022 08:47:08 +0200
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Yu Zhao <yuzhao@...gle.com>
Cc:     Mel Gorman <mgorman@...hsingularity.net>,
        Nicolas Saenz Julienne <nsaenzju@...hat.com>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Michal Hocko <mhocko@...nel.org>,
        Hugh Dickins <hughd@...gle.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux-MM <linux-mm@...ck.org>
Subject: Re: [PATCH 7/7] mm/page_alloc: Replace local_lock with normal
 spinlock

Hi Andrew,

On 16.06.2022 01:04, Andrew Morton wrote:
> On Thu, 16 Jun 2022 00:48:55 +0200 Marek Szyprowski <m.szyprowski@...sung.com> wrote:
>
>> In the logs I see lots of errors like:
>>
>> BUG: sleeping function called from invalid context at
>> ./include/linux/sched/mm.h:274
>>
>> BUG: scheduling while atomic: systemd-udevd/288/0x00000002
>>
>> BUG: sleeping function called from invalid context at mm/filemap.c:2647
>>
>> however there are also a fatal ones like:
>>
>> Unable to handle kernel paging request at virtual address 00000000017a87b4
>>
>>
>> The issues seems to be a bit random. Looks like memory trashing.
>> Reverting $subject on top of current linux-next fixes all those issues.
>>
>>
> This?
>
> --- a/mm/page_alloc.c~mm-page_alloc-replace-local_lock-with-normal-spinlock-fix
> +++ a/mm/page_alloc.c
> @@ -183,8 +183,10 @@ static DEFINE_MUTEX(pcp_batch_high_lock)
>   	type *_ret;							\
>   	pcpu_task_pin();						\
>   	_ret = this_cpu_ptr(ptr);					\
> -	if (!spin_trylock_irqsave(&_ret->member, flags))		\
> +	if (!spin_trylock_irqsave(&_ret->member, flags)) {		\
> +		pcpu_task_unpin();					\
>   		_ret = NULL;						\
> +	}								\
>   	_ret;								\
>   })
>   
>
> I'll drop Mel's patch for next -next.

Yes, this fixes the issues I've observed. Feel free to add:

Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland