From nobody Thu Dec 18 08:13:21 2025 Received: from mail-pl1-f202.google.com (mail-pl1-f202.google.com [209.85.214.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E843D5EE97 for ; Fri, 6 Dec 2024 00:31:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733445107; cv=none; b=nO3Qag89YaHN86FZGbKxtvczrOw62fsVBqY6TPQcVm3S1pU6iGFLrkCIx7ehkV6mX7DuKGIDfFHYvLu+83Q7vGd8+ijd47MF9KeINV0p5fsk+dnkv1UF1TgyePZJsaeZjHynucev7epqk1uS1cFnSrfRJIPxR3jqNtCovtdnFHs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733445107; c=relaxed/simple; bh=7eooM8lictiogeSqDWNnopPiMIbG0zFPlbWX1bsoFTE=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=pAp/A4kryZ3X+xNILLErJ2np4NaXNwHdfkX32mSYv1aI0NqAZA8zz9BUtbDeVvseSfqkpm1NFLQo8Gv+6C9baHC+YEh+Q/ZDOYmp+4TYlBNOuYTS+su9K4mQfdLx31ybq9f5XIHwfrUPos2MSC/KGis2mhMA7k04sTUuM04P5gc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--yuzhao.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=3xJWIrak; arc=none smtp.client-ip=209.85.214.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--yuzhao.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="3xJWIrak" Received: by mail-pl1-f202.google.com with SMTP id d9443c01a7336-215b45a6e2aso15871965ad.2 for ; Thu, 05 Dec 2024 16:31:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1733445105; x=1734049905; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=KW2cgcwHB51Y5IYZaisd+Bp0HxAyG3VEQ4AUms4DlWs=; b=3xJWIrak1tSliUpXcCyShFM9HW3y+w1/uTZ/SeJDCrCyKOACGgj3FDBufNx8e9okx8 NPBmPdlQClLjUqaFtt6jS/gRwA0HCMc5ztfwuGxBzQPApV/93FSHvURXzqUdYu/4W7Hp meKarKNwxyQAUduvkbFxGBsmc9k7DHvqmFfhcOsV9+yDsxrYuZULdYuwoq0808rRvPo5 rPDA3TpG1N46IQiRt+W/99YMjwobvSnlW5bLlPYrdx6QNzdoZjsBlMoxnfy+OAFGAiFN +1zLcM8Hl9s9S23hHoLIHtDirc6lsrkWnfKQrZYnVYwcQ037GQheVZg6mL48cUuhV9H2 ZWmg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733445105; x=1734049905; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=KW2cgcwHB51Y5IYZaisd+Bp0HxAyG3VEQ4AUms4DlWs=; b=vtg0ul0IkoXwKgK07lZqHAUUb0ae5a5Mb75Fw3kZBHXKFD9yn2z1EuYdJl4ImkfkvD wPtGz9Y52Rj6RUw/ynr+bzytnmyuYr2WcPzg4LQTeEndhqnlPfMx9901WdKHEbCGy8Ik rimpPNngqPPTSG/aVeL+bzfgjPoRrc6pybYB1GPXKG0wUJX1J2urRov3inKCkQMrcjfV hx29qZl2JAPxcAAHyCT2Ct1ELQol/qI7Q9O2a1H7pyhXMV9c48SrJs73d9h0NMzWAb5b sv5dIOenRmdnaMZ5W+j3tV7g5R22TQ0Wx8MPZY22hQx1np3tov6YUNcAuI+oPqb9ns5w B73A== X-Forwarded-Encrypted: i=1; AJvYcCVmb3BNVHONxCOxtWS4Z7q7Ic0j+UT6iQ1VD2Efi4Ntj5LypRBRIFdSJTs40JmrJOm8jWXhYiXMjBQmjyE=@vger.kernel.org X-Gm-Message-State: AOJu0YzPanPuVlSshrmw8TPF2geHK7TxgHBJYmgIO+MDFYW3ekcjYfX9 //fDJZkPJ07ijdCfXVVHTy9WoiEeEsSrFyTJfEwxYQKL6hgolUPQwdMZwwTEyFcm97P/VJstr7M eRw== X-Google-Smtp-Source: AGHT+IGcBw64P6PC43lwi6CEzaODCf5NQzsvKmv+pkev0Vd7uHGWUIM2qXHUyE9c6qDAYcuhyiX00sGOta8= X-Received: from pllb6.prod.google.com ([2002:a17:902:e946:b0:215:83cc:b135]) (user=yuzhao job=prod-delivery.src-stubby-dispatcher) by 2002:a17:903:24d:b0:216:1367:7e3d with SMTP id d9443c01a7336-21614d67fc3mr14295335ad.31.1733445105156; Thu, 05 Dec 2024 16:31:45 -0800 (PST) Date: Thu, 5 Dec 2024 17:31:25 -0700 In-Reply-To: <20241206003126.1338283-1-yuzhao@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241206003126.1338283-1-yuzhao@google.com> X-Mailer: git-send-email 2.47.0.338.g60cca15819-goog Message-ID: <20241206003126.1338283-6-yuzhao@google.com> Subject: [PATCH mm-unstable v2 5/6] mm/mglru: rework refault detection From: Yu Zhao To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yu Zhao , Kairui Song , Kalesh Singh Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" With anon and file min_seq being able to move independently, rework workingset protection as well so that the comparison of refaults between anon and file is always on an equal footing. Specifically, make lru_gen_test_recent() return true for refaults happening within the distance of MAX_NR_GENS. For example, if min_seq of a type is max_seq-MIN_NR_GENS, refaults from min_seq-1, i.e., max_seq-MIN_NR_GENS-1, are also considered recent, since the distance max_seq-(max_seq-MIN_NR_GENS-1), i.e., MIN_NR_GENS+1 is less than MAX_NR_GENS. As an intermediate step to the final optimization, this change by itself should not have userspace-visiable effects beyond performance. Reported-by: Kairui Song Closes: https://lore.kernel.org/CAOUHufahuWcKf5f1Sg3emnqX+cODuR=3D2TQo7T4Gr= -QYLujn4RA@mail.gmail.com/ Signed-off-by: Yu Zhao Tested-by: Kalesh Singh --- mm/workingset.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/mm/workingset.c b/mm/workingset.c index ad181d1b8cf1..2c310c29f51e 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -260,11 +260,11 @@ static void *lru_gen_eviction(struct folio *folio) * Tests if the shadow entry is for a folio that was recently evicted. * Fills in @lruvec, @token, @workingset with the values unpacked from sha= dow. */ -static bool lru_gen_test_recent(void *shadow, bool file, struct lruvec **l= ruvec, +static bool lru_gen_test_recent(void *shadow, struct lruvec **lruvec, unsigned long *token, bool *workingset) { int memcg_id; - unsigned long min_seq; + unsigned long max_seq; struct mem_cgroup *memcg; struct pglist_data *pgdat; =20 @@ -273,8 +273,10 @@ static bool lru_gen_test_recent(void *shadow, bool fil= e, struct lruvec **lruvec, memcg =3D mem_cgroup_from_id(memcg_id); *lruvec =3D mem_cgroup_lruvec(memcg, pgdat); =20 - min_seq =3D READ_ONCE((*lruvec)->lrugen.min_seq[file]); - return (*token >> LRU_REFS_WIDTH) =3D=3D (min_seq & (EVICTION_MASK >> LRU= _REFS_WIDTH)); + max_seq =3D READ_ONCE((*lruvec)->lrugen.max_seq); + max_seq &=3D EVICTION_MASK >> LRU_REFS_WIDTH; + + return abs_diff(max_seq, *token >> LRU_REFS_WIDTH) < MAX_NR_GENS; } =20 static void lru_gen_refault(struct folio *folio, void *shadow) @@ -290,7 +292,7 @@ static void lru_gen_refault(struct folio *folio, void *= shadow) =20 rcu_read_lock(); =20 - recent =3D lru_gen_test_recent(shadow, type, &lruvec, &token, &workingset= ); + recent =3D lru_gen_test_recent(shadow, &lruvec, &token, &workingset); if (lruvec !=3D folio_lruvec(folio)) goto unlock; =20 @@ -331,7 +333,7 @@ static void *lru_gen_eviction(struct folio *folio) return NULL; } =20 -static bool lru_gen_test_recent(void *shadow, bool file, struct lruvec **l= ruvec, +static bool lru_gen_test_recent(void *shadow, struct lruvec **lruvec, unsigned long *token, bool *workingset) { return false; @@ -432,8 +434,7 @@ bool workingset_test_recent(void *shadow, bool file, bo= ol *workingset, bool recent; =20 rcu_read_lock(); - recent =3D lru_gen_test_recent(shadow, file, &eviction_lruvec, - &eviction, workingset); + recent =3D lru_gen_test_recent(shadow, &eviction_lruvec, &eviction, work= ingset); rcu_read_unlock(); return recent; } --=20 2.47.0.338.g60cca15819-goog