From: sashiko-bot@kernel.org
To: "SJ Park" <sj@kernel.org>
Cc: damon@lists.linux.dev
Subject: Re: [PATCH 1/8] mm/damon/core: skip applying scheme if region split for quota fails
Date: Tue, 01 Sep 2026 13:28:24 +0000 [thread overview]
Message-ID: <20260901132824.A11051F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260901131850.98037-2-sj@kernel.org>
> damos_apply_scheme() splits a region and apply the action to the
> subregion if it is needed for not violating the quota. The split
> operation (damon_split_region_at()) could fail for allocation failure.
> In the case, the quota could be violated. From the user's perspective,
> DAMOS becomes more aggressive than expected under the extreme situation.
> Handle the failure.
>
> The user impact is not critical. The failure of damon_split_region_at()
> is unlikely since it is arguably too small to fail. Also DAMOS being
> aggressive is limited to the single region. Users can set
> min_nr_regions to set the maximum size of each region. If it is
> reasonably set, the transient overhead shouldn't be critical.
>
> The issue was discovered [1] by Sashiko.
>
> [1] https://lore.kernel.org/20260718171523.87547-1-sj@kernel.org
>
> Fixes: 2b8a248d5873 ("mm/damon/schemes: implement size quota for schemes application speed control")
> Cc: <stable@vger.kernel.org> # 5.16.x
> Signed-off-by: SJ Park <sj@kernel.org>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260901131850.98037-1-sj@kernel.org?part=1
next prev parent reply other threads:[~2026-09-01 13:28 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-01 13:18 [PATCH 0/8] mm/damon: fix DAMOS bugs in core, paddr and vaddr SJ Park
2026-09-01 13:18 ` [PATCH 1/8] mm/damon/core: skip applying scheme if region split for quota fails SJ Park
2026-09-01 13:28 ` sashiko-bot [this message]
2026-09-01 13:18 ` [PATCH 2/8] mm/damon/paddr: respect folio end for DAMOS_STAT SJ Park
2026-09-01 13:27 ` sashiko-bot
2026-09-01 13:18 ` [PATCH 3/8] mm/damon/paddr: respect folio end for DAMOS actions except STAT SJ Park
2026-09-01 13:27 ` sashiko-bot
2026-09-01 13:18 ` [PATCH 4/8] mm/damon/vaddr: respect folio end for DAMOS_STAT SJ Park
2026-09-01 13:29 ` sashiko-bot
2026-09-01 13:18 ` [PATCH 5/8] mm/damon/vaddr: respect folio end for DAMOS_MIGRATE_{HOT,COLD} SJ Park
2026-09-01 13:26 ` sashiko-bot
2026-09-01 13:18 ` [PATCH 6/8] mm/damon/core: handle extreme memory state in damon_get_node_mem_bp() SJ Park
2026-09-01 13:35 ` sashiko-bot
2026-09-01 13:18 ` [PATCH 7/8] mm/damon/core: handle extreme memory state in get_node_memcg_used_bp() SJ Park
2026-09-01 13:41 ` sashiko-bot
2026-09-01 14:29 ` SJ Park
2026-09-01 13:18 ` [PATCH 8/8] mm/damon/core: handle extreme memory state in get_in_active_mem_bp() SJ Park
2026-09-01 13:36 ` sashiko-bot
2026-09-01 14:30 ` SJ Park
2026-09-01 14:30 ` [PATCH 0/8] mm/damon: fix DAMOS bugs in core, paddr and vaddr SJ Park
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