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

[Andrew Morton]

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.

> 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?