From nobody Tue Apr 7 15:27:22 2026 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 C2973C0502C for ; Sat, 27 Aug 2022 09:03:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235352AbiH0JDp (ORCPT ); Sat, 27 Aug 2022 05:03:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232280AbiH0JDU (ORCPT ); Sat, 27 Aug 2022 05:03:20 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93F6E29812 for ; Sat, 27 Aug 2022 02:03:18 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id x19so3562142plc.5 for ; Sat, 27 Aug 2022 02:03:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=references:in-reply-to:message-id:date:subject:cc:to:from:from:to :cc; bh=BnthDXQwip9Q9g75mHYulJV0YY03kw/VBBFjsliYM+A=; b=oJYgfkP4CP3NNgASktL4x7ODjcR3+HD3vZEwb07NsH609p1YZorhMYaw3uBuhLsaSu LZl0QJbmhi0jUukkNquR9EvRQwgy1orz6Qlv9WmSDCJ2x/HAt8SuOhGRRAclg8A068o0 H6cfWJZSar0AKRZ3vshQt11x9r00U0mbpgkpZSeMSS1XYqBpesH0f5xFjODDp+uhyaJ0 wXCO8cvU6XjxJ3rp9P2CjOjUN1KMdy5Uu2ZDItMGzCzspltNns3YcHzTAc1sFYUDEM2c 7UXykdPmR0Y8hi+57sQCVryu7P2/zquX1LjrNBhpnUvGRqEkT+xapyZkXJm6wZ35As4O X0Qg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=references:in-reply-to:message-id:date:subject:cc:to:from :x-gm-message-state:from:to:cc; bh=BnthDXQwip9Q9g75mHYulJV0YY03kw/VBBFjsliYM+A=; b=KD5yggKON17YPXVR8FHH5QBlkAS59ecf9/YQr9XZeLtNUUhnvoqF0AsUsrrE7MR54E qHwi17f0FcEcujRObf4f260ZCxl+5+tWDNQGs5LftRthc6eu3XfwzEtpJQrpPm0cf/PN M3hBNFmzCp+5chclxcVgEjh9NvxN2QFrjYEfK9Klfba7QDLSg34mesLRFAadZMWyTzSl dPVUaHHgYnEc+axRRNUpVqC2z9ol3gzd9rrph4aXAA8TYOoxxWPfxNRKwod717VUyXku k/OqAdAfmKMtm2nfH3gde51J+ggSK+n+Kg1WYU8DYHJONKGYv4CTtFrdchOn6PwXjA5R u2nw== X-Gm-Message-State: ACgBeo3tgZo0zpIq8FWtGzjYEDY+hoHm1wIPs8Z0Ch9rEBoXgPaz13Py gOszy3/MbMEC3w5aZfpgPQ== X-Google-Smtp-Source: AA6agR5cNMunEZrg1m2YWRxKj5/mEUiiHmC6GSFb8/9x4IAe9RfU9EnhJkNT4Z4v232c7q5+3WCBeQ== X-Received: by 2002:a17:90b:1644:b0:1fb:ab0c:c5bf with SMTP id il4-20020a17090b164400b001fbab0cc5bfmr8493090pjb.27.1661590998059; Sat, 27 Aug 2022 02:03:18 -0700 (PDT) Received: from localhost.localdomain ([43.132.141.8]) by smtp.gmail.com with ESMTPSA id s88-20020a17090a69e100b001fb09316a26sm2943332pjj.43.2022.08.27.02.03.15 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 27 Aug 2022 02:03:17 -0700 (PDT) From: xiakaixu1987@gmail.com X-Google-Original-From: kaixuxia@tencent.com To: sj@kernel.org, akpm@linux-foundation.org Cc: damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kaixu Xia Subject: [PATCH v2 2/2] mm/damon/vaddr: remove comparison between mm and last_mm when checking region accesses Date: Sat, 27 Aug 2022 17:02:51 +0800 Message-Id: <1661590971-20893-3-git-send-email-kaixuxia@tencent.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1661590971-20893-1-git-send-email-kaixuxia@tencent.com> References: <1661590971-20893-1-git-send-email-kaixuxia@tencent.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Kaixu Xia The damon regions that belong to the same damon target have the same 'struct mm_struct *mm', so it's unnecessary to compare the mm and last_mm objects among the damon regions in one damon target when checking accesses. But the check is necessary when the target changed in '__damon_va_check_accesses()', so we can simplify the whole operation by using the bool 'same_target' to indicate whether the target changed. Signed-off-by: Kaixu Xia Reviewed-by: SeongJae Park --- mm/damon/vaddr.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index e481f81c3efb..5f66c826ee3a 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -533,15 +533,14 @@ static bool damon_va_young(struct mm_struct *mm, unsi= gned long addr, * r the region to be checked */ static void __damon_va_check_access(struct mm_struct *mm, - struct damon_region *r) + struct damon_region *r, bool same_target) { - static struct mm_struct *last_mm; static unsigned long last_addr; static unsigned long last_page_sz =3D PAGE_SIZE; static bool last_accessed; =20 /* If the region is in the last checked page, reuse the result */ - if (mm =3D=3D last_mm && (ALIGN_DOWN(last_addr, last_page_sz) =3D=3D + if (same_target && (ALIGN_DOWN(last_addr, last_page_sz) =3D=3D ALIGN_DOWN(r->sampling_addr, last_page_sz))) { if (last_accessed) r->nr_accesses++; @@ -552,7 +551,6 @@ static void __damon_va_check_access(struct mm_struct *m= m, if (last_accessed) r->nr_accesses++; =20 - last_mm =3D mm; last_addr =3D r->sampling_addr; } =20 @@ -562,14 +560,17 @@ static unsigned int damon_va_check_accesses(struct da= mon_ctx *ctx) struct mm_struct *mm; struct damon_region *r; unsigned int max_nr_accesses =3D 0; + bool same_target; =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); + __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); } --=20 2.27.0