RE:(3) [PATCH] zram_drv: allow reclaim on bio_alloc

From: Jaewon Kim
Date: Tue Sep 07 2021 - 20:42:02 EST


>
>
>--------- Original Message ---------
>Sender : Minchan Kim <minchan@xxxxxxxxxx>
>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@xxxxxxxxxxxxx>
>> >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@xxxxxxxxxxx>
>> >> Signed-off-by: Jaewon Kim <jaewon31.kim@xxxxxxxxxxx>
>
>Looks reasonable to me.
>Feel free to add after dealing with Christoph's comment.
>
>Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
>
>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
>