Re: [PATCH v2] mm/page_alloc: fix defrag_mode for non-reclaimable allocations

[Dmitry Ilvokhin]

On Fri, May 22, 2026 at 07:54:26PM -0700, Andrew Morton wrote:
> On Fri, 22 May 2026 13:05:36 +0000 Dmitry Ilvokhin <d@xxxxxxxxxxxx> wrote:
> 
> > > How serious is this to our users when running real-world workloads?
> > 
> > We observed it on a few of the Meta workloads that adopted
> > defrag_mode=1.
> > 
> > For the service under load there were 85509 SLUB allocation failures
> > messages in dmesg within 2 hours. All of them are GFP_ATOMIC allocations
> > for skbuff_head_cache, despite free pages being available in other
> > migratetype freelists (~13 GB free).
> 
> For a single machine, I assume.

Yes, all of that data is from a single machine.

> 
> > Since it is networking path from the practical point of view, this means
> > dropped packets, failed RPC requests, tail latency spikes and overall
> > service degradation.
> 
> OK, thanks.   I assume 12 failures per second isn't a disaster, and that
> there's no need to fast-track this into 7.1?

Yes, I agree. No need to fast-track this.