Re: [PATCH v2] mm/memcontrol: fix reclaim_options leak in try_charge_memcg()

Yosry Ahmed
2026-03-18T22:06:34Z

On Wed, Mar 18, 2026 at 2:56 PM Bing Jiao <bingjiao@google.com> wrote:
>
> In try_charge_memcg(), the 'reclaim_options' variable is initialized
> once at the start of the function. However, the function contains a
> retry loop. If reclaim_options were modified during an iteration
> (e.g., by encountering a memsw limit), the modified state would
> persist into subsequent retries.
>
> This leads to incorrect reclaim behavior. Specifically,
> MEMCG_RECLAIM_MAY_SWAP is cleared when the combined memcg->memsw limit
> is reached. After reclaimation attemps, a subsequent retry may
> successfully charge memcg->memsw but fail on the memcg->memory charge.
> In this case, swapping should be permitted, but the carried-over state
> prevents it.
>
> Fix by moving the initialization of 'reclaim_options' inside the
> retry loop, ensuring a clean state for every reclaim attempt.
>
> Fixes: 73b73bac90d9 ("mm: vmpressure: don't count proactive reclaim in vmpressure")

The Fixes tag is still wrong, see my previous reply.