From nobody Mon Nov 25 00:16:37 2024 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 ACD911C9ED2; Thu, 31 Oct 2024 18:38:03 +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=1730399883; cv=none; b=NH2ftcEXbuhvDsz+5UZIiIcpmep7qQNX5OHETctpm0i+R0InpoKVlIqONsDQlW+d8gN60Drge/B5OYSCi53oJDcxy5OPNtMl4FI8k2eetGUkqooSKrUQiq0xQOukNq1iJOn2yBo9k5tuq+P1sMqAXtJrouLYMHtjB79KO8tGOfY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730399883; c=relaxed/simple; bh=L0OOFAcas3acRh+BRifsG3N6Sbsa4Qrr4fl+oy8M5uA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=TiE+DMCkSNpZfD6WnAr2l0+E3GmgpT5aKxE9XlroBbT/d/U/TZOoAZ1FN40Konplg1zf270TSFrLmRyj+h9JtBnX4Ee2Ew1eWAjenAEzQ97/HDMmWmhBF3uaUYdQpEVEcCUwh7p2F3nT5PgseD5IL7sCHj/XeK/8m7uGaYwNS5U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g0P16FYT; 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="g0P16FYT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F704C4CED1; Thu, 31 Oct 2024 18:38:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730399883; bh=L0OOFAcas3acRh+BRifsG3N6Sbsa4Qrr4fl+oy8M5uA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g0P16FYTS9DnqQ14GhTEt6IbNDNM+8nRMCJYKMr4VnOSTv+27cQyXSIbjCefOL9KZ mDyvoyTBeBxmslifg0hATNkapdR1tV6Z+zWEvC75ed4xObZEwlahgRv4dadBxmuclo z1oj7KAkBMuqJplhnZ9rvzT22HwZyV9LxGiF4nUT6DGZwq8qNQYjXVLj9HNH7u76iL 92Go4qFwtmoG9dJV02X4z8D6l0lMzPzjO5C8ptBvgUK0t60WBe85iP3UPEBImoHUuX PNwI1+0H2G3T6weBaN3q4A+1Ue7MsGmNTLSm5tKvoPkEDOV2nJFchrQkWsb5J3Ry17 +BLbh7BR8+bCA== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, stable@vger.kernel.org Subject: [PATCH 2/2] mm/damon/core: handle zero schemes apply interval Date: Thu, 31 Oct 2024 11:37:57 -0700 Message-Id: <20241031183757.49610-3-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241031183757.49610-1-sj@kernel.org> References: <20241031183757.49610-1-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 logics to determine if this is the time to apply damos schemes assumes next_apply_sis is always set larger than current passed_sample_intervals. And therefore assume continuously incrementing passed_sample_intervals will make it reaches to the next_apply_sis in future. The logic hence does apply the scheme and update next_apply_sis only if passed_sample_intervals is same to next_apply_sis. If Schemes apply interval is set as zero, however, next_apply_sis is set same to current passed_sample_intervals, respectively. And passed_sample_intervals is incremented before doing the next_apply_sis check. Hence, next_apply_sis becomes larger than next_apply_sis, and the logic says it is not the time to apply schemes and update next_apply_sis. In other words, DAMON stops applying schemes until passed_sample_intervals overflows. Based on the documents and the common sense, a reasonable behavior for such inputs would be applying the schemes for every sampling interval. Handle the case by removing the assumption. Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interv= al") Cc: # 6.7.x Signed-off-by: SeongJae Park --- mm/damon/core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 931526fb2d2e..511c3f61ab44 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1412,7 +1412,7 @@ static void damon_do_apply_schemes(struct damon_ctx *= c, damon_for_each_scheme(s, c) { struct damos_quota *quota =3D &s->quota; =20 - if (c->passed_sample_intervals !=3D s->next_apply_sis) + if (c->passed_sample_intervals < s->next_apply_sis) continue; =20 if (!s->wmarks.activated) @@ -1636,7 +1636,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c) bool has_schemes_to_apply =3D false; =20 damon_for_each_scheme(s, c) { - if (c->passed_sample_intervals !=3D s->next_apply_sis) + if (c->passed_sample_intervals < s->next_apply_sis) continue; =20 if (!s->wmarks.activated) @@ -1656,9 +1656,9 @@ static void kdamond_apply_schemes(struct damon_ctx *c) } =20 damon_for_each_scheme(s, c) { - if (c->passed_sample_intervals !=3D s->next_apply_sis) + if (c->passed_sample_intervals < s->next_apply_sis) continue; - s->next_apply_sis +=3D + s->next_apply_sis =3D c->passed_sample_intervals + (s->apply_interval_us ? s->apply_interval_us : c->attrs.aggr_interval) / sample_interval; } --=20 2.39.5