From nobody Fri Dec 19 07:31:05 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7EC9CEE3F01 for ; Fri, 15 Sep 2023 02:53:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231768AbjIOCxN (ORCPT ); Thu, 14 Sep 2023 22:53:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44904 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231648AbjIOCxI (ORCPT ); Thu, 14 Sep 2023 22:53:08 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F6322701 for ; Thu, 14 Sep 2023 19:53:04 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68B15C433CA; Fri, 15 Sep 2023 02:53:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694746383; bh=i00VYLhoAf7cwF/8O1Xi88bbaOl2lSsV4k5ng0qJ0ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EyWd6QeH+I+otwhxDe5iLd5XAOviRv5NU62+pG7wOYSt1RxJd562R/9kRGV/14S6k wqwgK3S/aoyzhC6ERZqSSiw7JvU7BAbifNwCKIe6Ic1N++Fm4YodPXqekKh7wy5E4c frf4PtL+Dv7zzGaMntbeugmrQFPZnEwcCuwZ6MVTdQMvr7clAKApk58dlqzx4D9XB7 gFmgUFdVfZXcHnVsiUAYX4nj2eQscAJwIuXzXjzAOvHwZF0ZRQvEYWdpSJfowFNMuu CkJENgkBPYUg94GulS9lebSqQJdp3mZ2b0vLC1KWqzgCeo/tyq22w10Ies9ncnlHit 8JGVkX6Fe/OWA== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/8] mm/damon/vaddr: call damon_update_region_access_rate() always Date: Fri, 15 Sep 2023 02:52:45 +0000 Message-Id: <20230915025251.72816-3-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230915025251.72816-1-sj@kernel.org> References: <20230915025251.72816-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When getting mm_struct of the monitoring target process fails, there wil be no need to increase the access rate counter (nr_accesses) of the regions for the process. Hence, damon_va_check_accesses() skips calling damon_update_region_access_rate() in the case. This breaks the assumption that damon_update_region_access_rate() is called for every region, for every sampling interval. Call the function for every region even in the case. This might increase the overhead in some cases, but such case would not be frequent, so no significant impact is really expected. Signed-off-by: SeongJae Park --- mm/damon/vaddr.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index 7fc0bda73b4c..e36303271f9d 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -563,6 +563,11 @@ static void __damon_va_check_access(struct mm_struct *= mm, static unsigned long last_folio_sz =3D PAGE_SIZE; static bool last_accessed; =20 + if (!mm) { + damon_update_region_access_rate(r, false); + return; + } + /* If the region is in the last checked page, reuse the result */ if (same_target && (ALIGN_DOWN(last_addr, last_folio_sz) =3D=3D ALIGN_DOWN(r->sampling_addr, last_folio_sz))) { @@ -586,15 +591,14 @@ static unsigned int damon_va_check_accesses(struct da= mon_ctx *ctx) =20 damon_for_each_target(t, ctx) { mm =3D damon_get_mm(t); - if (!mm) - continue; same_target =3D false; damon_for_each_region(r, t) { __damon_va_check_access(mm, r, same_target); max_nr_accesses =3D max(r->nr_accesses, max_nr_accesses); same_target =3D true; } - mmput(mm); + if (mm) + mmput(mm); } =20 return max_nr_accesses; --=20 2.25.1