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Subject: RE:(3) [PATCH] zram_drv: allow reclaim on bio_alloc
Reply-To: jaewon31.kim@samsung.com
Sender: Jaewon Kim <jaewon31.kim@samsung.com>
From:   Jaewon Kim <jaewon31.kim@samsung.com>
To:     Minchan Kim <minchan@kernel.org>,
        Jaewon Kim <jaewon31.kim@samsung.com>
CC:     Christoph Hellwig <hch@infradead.org>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        YongTaek Lee <ytk.lee@samsung.com>,
        "jaewon31.kim@gmail.com" <jaewon31.kim@gmail.com>
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Date:   Wed, 08 Sep 2021 09:41:46 +0900
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> 
> 
>--------- Original Message ---------
>Sender : Minchan Kim <minchan@kernel.org>
>Date : 2021-09-08 02:00 (GMT+9)
>Title : Re: (2) [PATCH] zram_drv: allow reclaim on bio_alloc
> 
>Hi Jaewon,
> 
>On Mon, Sep 06, 2021 at 06:14:48PM +0900, Jaewon Kim wrote:
>> > 
>> > 
>> >--------- Original Message ---------
>> >Sender : Christoph Hellwig <hch@infradead.org>
>> >Date : 2021-09-06 17:39 (GMT+9)
>> >Title : Re: [PATCH] zram_drv: allow reclaim on bio_alloc
>> > 
>> >On Mon, Sep 06, 2021 at 02:29:26PM +0900, Jaewon Kim wrote:
>> >> The read_from_bdev_async is not called on atomic context. So GFP_NOIO is
>> >> available rather than GFP_ATOMIC. If there were reclaimable pages with
>> >> GFP_NOIO, we can avoid allocation failure and page fault failure.
>> >> 
>> >> Reported-by: Yong-Taek Lee <ytk.lee@samsung.com>
>> >> Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
> 
>Looks reasonable to me.
>Feel free to add after dealing with Christoph's comment.
> 
>Acked-by: Minchan Kim <minchan@kernel.org>
> 
>Thank you.

Thank you, I will send v2 patch soon.

> 
>> >> ---
>> >>  drivers/block/zram/zram_drv.c | 2 +-
>> >>  1 file changed, 1 insertion(+), 1 deletion(-)
>> >> 
>> >> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
>> >> index fcaf2750f68f..53be528a39a2 100644
>> >> --- a/drivers/block/zram/zram_drv.c
>> >> +++ b/drivers/block/zram/zram_drv.c
>> >> @@ -587,7 +587,7 @@ static int read_from_bdev_async(struct zram *zram, struct bio_vec *bvec,
>> >>  {
>> >>          struct bio *bio;
>> >>  
>> >> -        bio = bio_alloc(GFP_ATOMIC, 1);
>> >> +        bio = bio_alloc(GFP_NOIO|__GFP_HIGHMEM, 1);
>> > 
>> >Passing __GFP_HIGHMEM to bio_alloc does not make any sense whatsoever.
>> > 
>> Correct, let me remove __GFP_HIGHMEM if I send v2 patch.
>> Thank you
>