Re: [PATCH v4] mm/page_alloc: avoid direct compaction for costly __GFP_NORETRY allocations

[Vlastimil Babka (SUSE)]

On 9/18/26 11:28 PM, Andrew Morton wrote:
> On Fri, 18 Sep 2026 09:05:40 +0200 "Vlastimil Babka (SUSE)" <vbabka@xxxxxxxxxx> wrote:
> 
>>>> Unless I'm mistaken about that MIGRATE_HIGHATOMIC part, it seems all sashiko
>>>> concerns can be dismissed and then indeed v4 is the better version.
>>>
>>> It looks like a real issue to me, but one that already exists
>>> independent of Salvatore's change.
>>
>> But Salvatore's change (v4, not v5 IIUC) will make it worse because
>> __GFP_DIRECT_RECLAIM + __GFP_NORETRY costly order opportunistic attempts
>> with fallback will start eating the highatomic reserves too?
>>
>> In that case the fix for this should probably be part of the same PR to
>> Linus and be also stable with Fixes: 281dd25c1a01
> 
> Oh.  I thought this was settled.
> 
> I've removed "mm/page_alloc: avoid direct compaction for costly
> __GFP_NORETRY allocations" v4 from mm-hotfixes-stable and re-added it
> to mm-hotfixes-unstable and I'll await developments.

Since it's fixing a bug from 6.6 it would actually IMHO be better to
target 7.4 and not treat it as an urgent 7.3 fix.