From nobody Tue Feb 10 03:00:14 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0CFC218ADD; Thu, 16 Oct 2025 21:47:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760651262; cv=none; b=MO/hxOJXatYDtu27OlhLXF9ozSwf908BAkHCwk/Oq0Z0bxJshUC5qbgbZm2nSNgSsWuEW0S5B5y1NS2E2xncLp2Xu795rYstaKzSJ9K4pKKSxsSgAETiVxRUxaEiqRVegd3sUDHfQ7ditN1jDRclJbvaqe7R9A2dADQgn5iW6lk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760651262; c=relaxed/simple; bh=UUnCkanvoPf80rfrjE5y8KYyMoRR90dpdf30uhflryc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TLzTAGJ3gUVjvybwAZt+vDhCYRvaqbYHs6bIyFLLucdYv7G7azD01+miz5ceRgAUqFM2vrByd/4J0A79eww6Uixuyc8OXwEjhXjbZ59dpe9Qb6njv9X9E1gsKLIIXmDse3INdgVDj5v1tgoptLpq7mNAgHUY2VrZaG7Vo1QAjhA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j5RZ9Zd9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="j5RZ9Zd9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DFE6C116B1; Thu, 16 Oct 2025 21:47:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760651262; bh=UUnCkanvoPf80rfrjE5y8KYyMoRR90dpdf30uhflryc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=j5RZ9Zd9vlngL+iwpjUimBM6yuyRDpeqGgN3hWpLniLlmPJVypAaKX3AROSCCMpck 5u0FhXhO86Zusk/grZihXHecJ71vNGlsWNfjT/8D9v9J5KLJ3vHEPLe4ap0EQYIK4q Pdw7KMbhrudeHwlhdg+1QbWa+aC09cQiX/ywv2bwUrkvrizFGsv6cD2tN0NxLOFYTD R2IrJLDlG/wZrjhLPfLc4w9fsQby8mPBLMhMQgGuLJTbjWdeO1yPJHzWKhW/T0PLLL TMgVXl3kSACRYTA8y8z3i5Cr8csflXLxQqHHELklyOAZMvSn5SucfA+dANi4ghXXiY 7JC3CFvPFrnDg== From: SeongJae Park To: Cc: SeongJae Park , Andrew Morton , bijan311@gmail.com, damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 1/5] mm/damon/core: add damon_target->obsolete for pin-point removal Date: Thu, 16 Oct 2025 14:47:28 -0700 Message-ID: <20251016214736.84286-2-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251016214736.84286-1-sj@kernel.org> References: <20251016214736.84286-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" DAMON's monitoring targets parameters update function, damon_commit_targets(), is not providing a way to remove a target in the middle of existing targets list. Extend the API by adding a field to struct damon_target. If the field of a damon_commit_targets() source target is set, it indicates the matcing target on the existing targets list is obsolete. damon_commit_targets() understands that and remove those from the list, while respecting the index based matching for other non-obsolete targets. Signed-off-by: SeongJae Park Reviewed-by: Bijan Tabatabai --- include/linux/damon.h | 6 ++++++ mm/damon/core.c | 10 +++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/linux/damon.h b/include/linux/damon.h index 524dea87cac7..8a7b45b9e40d 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -92,17 +92,23 @@ struct damon_region { * @nr_regions: Number of monitoring target regions of this target. * @regions_list: Head of the monitoring target regions of this target. * @list: List head for siblings. + * @obsolete: Whether the commit destination target is obsolete. * * Each monitoring context could have multiple targets. For example, a co= ntext * for virtual memory address spaces could have multiple target processes.= The * @pid should be set for appropriate &struct damon_operations including t= he * virtual address spaces monitoring operations. + * + * @obsolte is used only for damon_commit_targets() source targets, to spe= cify + * the matching destination targets are obsolte. Read damon_commit_target= s() + * to see how it is handled. */ struct damon_target { struct pid *pid; unsigned int nr_regions; struct list_head regions_list; struct list_head list; + bool obsolete; }; =20 /** diff --git a/mm/damon/core.c b/mm/damon/core.c index 70e66562a1b3..3242a9573db0 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -492,6 +492,7 @@ struct damon_target *damon_new_target(void) t->nr_regions =3D 0; INIT_LIST_HEAD(&t->regions_list); INIT_LIST_HEAD(&t->list); + t->obsolete =3D false; =20 return t; } @@ -1213,7 +1214,11 @@ static int damon_commit_targets( =20 damon_for_each_target_safe(dst_target, next, dst) { src_target =3D damon_nth_target(i++, src); - if (src_target) { + /* + * If src target is obsolete, do not commit the parameters to + * the dst target, and further remove the dst target. + */ + if (src_target && !src_target->obsolete) { err =3D damon_commit_target( dst_target, damon_target_has_pid(dst), src_target, damon_target_has_pid(src), @@ -1236,6 +1241,9 @@ static int damon_commit_targets( damon_for_each_target_safe(src_target, next, src) { if (j++ < i) continue; + /* target to remove has no matching dst */ + if (src_target->obsolete) + return -EINVAL; new_target =3D damon_new_target(); if (!new_target) return -ENOMEM; --=20 2.47.3