Re: [PATCH] mm/page_alloc: only set ALLOC_HIGHATOMIC for __GPF_HIGH allocations

[Thadeu Lima de Souza Cascardo <cascardo@igalia.com>]

On Fri, Aug 29, 2025 at 11:30:17AM +0200, Vlastimil Babka wrote:
> On 8/29/25 10:56, Sergey Senozhatsky wrote:
> > On (25/08/29 10:38), Vlastimil Babka wrote:
> >> On 8/29/25 10:36, Vlastimil Babka wrote:
> >> > On 8/14/25 19:22, Thadeu Lima de Souza Cascardo wrote:
> > [..]
> >> > Agreed with others that this change matches the original intention and it
> >> > must have been an oversight. Also found nothing to the contrary in the
> >> > original threads.
> >> 
> >> Oops, forgot to add
> >> 
> >> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> > 
> > Thank you!
> > 
> > FWIW
> > Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> > 
> > This needs Cc: stable@vger.kernel.org  all the way down to 5.15,
> > as far as I can tell.
> 
> If that problem bothers users of LTS kernels in that range, we can do that.
> I wonder a bit how it was only found out now as a regression in the
> browser/desktop environment test if it's that old? Is there another factor
> i.e. some new frequesnt source of allocations that trigger it?

That is not. It is just that there was an upgrade all the way back from 5.4
and, then, I caught this while doing some code inspection and reviewing the
patchset I referred to.

Well, I also tested that it really happens and caught a unix socket skb
allocation triggering that as it masks off __GFP_DIRECT_RECLAIM.

Cascardo.