On Fri, Oct 27, 2023 at 07:32:54PM +0200, Mikulas Patocka wrote:
> So, we got no reponse from the MM maintainers. Marek - please try this
yes, how dare i go on holiday. i'll look at this when i'm back.
probably.
> patch on all the machines where you hit the bug and if you still hit the
> bug with this patch, report it.
>
> Mikulas
>
>
>
> From: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> Subject: [PATCH] dm-crypt: don't allocate large compound pages
>
> It was reported that the patch 5054e778fcd9cd29ddaa8109077cd235527e4f94
> ("dm crypt: allocate compound pages if possible") causes intermittent
> freezes [1].
>
> So far, it is not clear what is the root cause. It was reported that with
> the allocation order 3 or lower it works [1], so we restrict the order to
> 3 (that is PAGE_ALLOC_COSTLY_ORDER).
>
> [1] https://www.spinics.net/lists/dm-devel/msg56048.html
>
> Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> Reported-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
> Tested-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # v6.5+
> Fixes: 5054e778fcd9 ("dm crypt: allocate compound pages if possible")
>
> ---
> drivers/md/dm-crypt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6/drivers/md/dm-crypt.c
> ===================================================================
> --- linux-2.6.orig/drivers/md/dm-crypt.c
> +++ linux-2.6/drivers/md/dm-crypt.c
> @@ -1679,7 +1679,7 @@ static struct bio *crypt_alloc_buffer(st
> unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
> gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM;
> unsigned int remaining_size;
> - unsigned int order = MAX_ORDER - 1;
> + unsigned int order = PAGE_ALLOC_COSTLY_ORDER;
>
> retry:
> if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM))
