From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794342113; b=ATbEpeZV3oohT0Pii5a2884cgC3bLARwnqmXTwENZznROFPEEnHjSS+PttE4QIJ+Ayio +t5HdfE2xoP10t9EH9ejkc8ccaOEj0KTmhf5NKlTj2bUxB8UwG2QIQjCMSoWcRTjijI+w q9buMOnAewk/pFNZjihpq33K1BE/G8+iMCMvuUrt5eok+XmfJBpueMm5FzlCvuxzka0/j wXAC/2DsL4EvqVEGam5TbQc8pmCES4u+LFUPtT2wsJ96Zk/f1+93TPqSntbmIincb+OUN BHtNOuwEI48u4YltpnAKZEKFg5XufMBxxXq2BeYTMfrx5dcs708pKGZCJ9h3z7XqgrQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794342113; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-Id:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=7JJu+pEdf5RpGWIdVT2qEG1znfhrEKZZwrV03y/iAoI=; b=F8XuAmsyy37wT6RzS6L0tZk7xyxtkFgknS9Lsq5ebuwoGCPTc6brr1foVPDSQ9d1Gd68 BdgNZsq0dE6FuHOR8mQpWCMyczHoohLXqrxGRuVUj/WdTnJv6sZ3DKi8fwYkLNZWMhsBP hZXHwBpo5jU4MFJAgx3uJI1Tq8OhdPG1J2eK9gI2w2H6BnxzbnzYAu6NT02PlZz0GNcNA vwg2LjU/QvBtQEDqB2OACTf9u7BRCFSyfdb9PlLEYHlBrHb0D3zTinlkARgYky4EYycWV bWv1RndsFL2EAxiloYTxy4r9bavvjiOc1umt3R3u32H4utzTN7a3hoR3rHaJp/68CyQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=miFoIWG3; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29655606A326 for ; Tue, 10 Nov 2026 20:21:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=miFoIWG3 Received: by smtp.kernel.org (Postfix) with ESMTPSA id D905E1F008A2; Tue, 10 Nov 2026 20:21:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794342112; bh=7JJu+pEdf5RpGWIdVT2qEG1znfhrEKZZwrV03y/iAoI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=miFoIWG3dgLkKgXAj1MJKO5fngFq5HWLOOs4WJ/f/Orob1wWYcjdTWw/j+T4tRVN0 BnI7+CLwya1zmINYBZxcTChBr312r/qscW2ZELYLZK4hA1HMoHyeC3r1+aYD3Ffzrf q3VVIBdamdMDlXGzDY2VnLRYS5YCOm/lOdVWAscZmUa5amK0xr8EzTn5NJsnbkcB3B Ot0sA1N+nMV7B3jRYn4WnIVtRIy9zARMLn9lwrIeERuCokDb4YjuU6d2GiA/BEiEiv rhUYMMIcaO1fU2juotsMOIg4eKrWV0vjx4jNWd+KvQLxl9AWEe2QHj+yMgybjJBfu5 tPboBO33YPqcw== From: "Barry Song (Xiaomi)" To: akpm@linux-foundation.org, linux-mm@kvack.org Cc: axelrasmussen@google.com, baolin.wang@linux.alibaba.com, baoquan.he@linux.dev, hannes@cmpxchg.org, hui.zhu@linux.dev, kasong@tencent.com, kunwu.chan@gmail.com, liam@infradead.org, lianux.mm@gmail.com, linux-kernel@vger.kernel.org, liuxiang.277@bytedance.com, lyugaofei@xiaomi.com, mhocko@kernel.org, mhocko@suse.com, qi.zheng@linux.dev, ridong.chen@linux.dev, rppt@kernel.org, ryncsn@gmail.com, shakeel.butt@linux.dev, surenb@google.com, wangzicheng@honor.com, weixugc@google.com, yuanchu@google.com, zhangbo56@xiaomi.com, zhuhui@kylinos.cn, sidchintamaneni@gmail.com, Barry Song , Kunwu Chan Subject: [PATCH v6 15/15] mm/mglru: Avoid scan anon while swapcache is low for GFP_NOIO allocation Date: Wed, 11 Nov 2026 04:20:25 +0800 Message-Id: <20261110202025.25736-16-baohua@kernel.org> X-Mailer: git-send-email 2.39.3 (Apple Git-146) In-Reply-To: <20261110202025.25736-1-baohua@kernel.org> References: <20261110202025.25736-1-baohua@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Bo Zhang With GFP_NOIO, we cannot reclaim anon folios unless they are in the swap cache. CLRU skips anon reclaim when the swap cache is very low by commit 74d9aa0d8e98 ("mm: vmscan: avoid anon scanning for GFP_NOIO with low swapcache"). Apply the same logic to MGLRU. The new scan-budget-based mechanism makes this straightforward to implement. Thanks also to Xiang Liu, who previously attempted to fix this before we had the scan-budget-based model [1]. [1] https://lore.kernel.org/linux-mm/179248830836.1744016.8424217811286616919.noio-mglru-rfc-v2@bytedance.com/ Cc: Xiang Liu Signed-off-by: Bo Zhang Co-developed-by: Barry Song (Xiaomi) Signed-off-by: Barry Song (Xiaomi) Reviewed-by: Kunwu Chan --- mm/vmscan.c | 44 ++++++++++++++++++++++---------------------- 1 file changed, 22 insertions(+), 22 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 379339220878..fa0245a07caa 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -272,13 +272,6 @@ static inline bool reclaimable_anon_is_low(struct mem_cgroup *memcg, if (!sc || (sc->gfp_mask & __GFP_IO)) return false; - /* - * FIXME: MGLRU doesn't fully respect can_reclaim_anon_pages() for the - * scanning type, so only apply this to the traditional LRU for now. - */ - if (lru_gen_enabled()) - return false; - if (memcg) { struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); @@ -4206,12 +4199,14 @@ static void set_initial_priority(struct pglist_data *pgdat, struct scan_control sc->priority = clamp(priority, DEF_PRIORITY / 2, DEF_PRIORITY); } -static void lruvec_evictable_size(struct lruvec *lruvec, int swappiness, - unsigned long nr[]) +static void lruvec_evictable_size(struct lruvec *lruvec, struct scan_control *sc, + int swappiness, unsigned long nr[]) { int type; unsigned long seq; struct lru_gen_folio *lrugen = &lruvec->lrugen; + struct mem_cgroup *memcg = lruvec_memcg(lruvec); + int nid = lruvec_pgdat(lruvec)->node_id; DEFINE_MAX_SEQ(lruvec); DEFINE_MIN_SEQ(lruvec); @@ -4219,6 +4214,8 @@ static void lruvec_evictable_size(struct lruvec *lruvec, int swappiness, nr[LRU_GEN_FILE] = 0; for_each_evictable_type(type, swappiness) { + if (type == LRU_GEN_ANON && !can_reclaim_anon_pages(memcg, nid, sc)) + continue; for (seq = min_seq[type]; seq <= max_seq; seq++) nr[type] += lruvec_gen_size(lrugen, type, seq, sc->reclaim_idx + 1); } @@ -4229,7 +4226,7 @@ static bool lruvec_is_sizable(struct lruvec *lruvec, struct scan_control *sc) unsigned long total, sizes[ANON_AND_FILE]; int swappiness = get_swappiness(lruvec, sc); - lruvec_evictable_size(lruvec, swappiness, sizes); + lruvec_evictable_size(lruvec, sc, swappiness, sizes); total = sizes[LRU_GEN_ANON] + sizes[LRU_GEN_FILE]; /* whether the size is big enough to be helpful */ @@ -4893,23 +4890,19 @@ static void lru_gen_balance_scan(struct lruvec *lruvec, struct scan_control *sc, { struct lru_gen_folio *lrugen = &lruvec->lrugen; u64 refault_rate[ANON_AND_FILE], anon_factor, file_factor; - u64 anon_scan, file_scan, total; + u64 anon_scan, file_scan; u64 anon_weight, file_weight; int size_bias; - total = nr[LRU_GEN_ANON] + nr[LRU_GEN_FILE]; - if (!total) - return; - - if (swappiness <= MIN_SWAPPINESS) { + if (swappiness <= MIN_SWAPPINESS) nr[LRU_GEN_ANON] = 0; - nr[LRU_GEN_FILE] = min_t(u64, total_scan, nr[LRU_GEN_FILE]); - return; - } - if (swappiness == SWAPPINESS_ANON_ONLY) { + if (swappiness == SWAPPINESS_ANON_ONLY) nr[LRU_GEN_FILE] = 0; + + if (!nr[LRU_GEN_ANON] || !nr[LRU_GEN_FILE]) { nr[LRU_GEN_ANON] = min_t(u64, total_scan, nr[LRU_GEN_ANON]); + nr[LRU_GEN_FILE] = min_t(u64, total_scan, nr[LRU_GEN_FILE]); return; } @@ -5113,12 +5106,19 @@ static bool should_run_aging(struct lruvec *lruvec, unsigned long max_seq, struct scan_control *sc, int swappiness, bool do_balance) { + struct pglist_data *pgdat = lruvec_pgdat(lruvec); + struct mem_cgroup *memcg = lruvec_memcg(lruvec); DEFINE_MIN_SEQ(lruvec); /* have to run aging, since eviction is not possible anymore */ if (evictable_min_seq(min_seq, swappiness) + MIN_NR_GENS > max_seq) return true; + /* run aging when GFP_NOIO limits anon reclaim with few swapcache folios */ + if (swappiness && min_seq[LRU_GEN_FILE] + MIN_NR_GENS > max_seq && + reclaimable_anon_is_low(memcg, pgdat->node_id, sc)) + return true; + /* try to avoid aging, do gentle reclaim at the default priority */ if (sc->priority == DEF_PRIORITY) return false; @@ -5137,7 +5137,7 @@ static void lru_gen_prepare_scan(struct lruvec *lruvec, struct scan_control *sc, { unsigned long total; - lruvec_evictable_size(lruvec, swappiness, nr_to_scan); + lruvec_evictable_size(lruvec, sc, swappiness, nr_to_scan); total = nr_to_scan[LRU_GEN_ANON] + nr_to_scan[LRU_GEN_FILE]; /* Just scrape all pages calculated above if this memcg was deleted */ @@ -5888,7 +5888,7 @@ static int run_eviction(struct lruvec *lruvec, unsigned long seq, struct scan_co if (sc->nr_reclaimed >= nr_to_reclaim) return 0; - lruvec_evictable_size(lruvec, swappiness, nr_to_scan); + lruvec_evictable_size(lruvec, sc, swappiness, nr_to_scan); lru_gen_balance_scan(lruvec, sc, swappiness, nr_to_reclaim - sc->nr_reclaimed, nr_to_scan); -- 2.34.1