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b=LLGp4/+8kHfG3XaY9MW48NgLFV00TpK3bldoGF2u2IsEIe01KBpuQWuKk7hhMBjPQ JKhplgPH506WX1RmYtr3rcCl5N1uZ3qTepV2ikpQMkVY9e3Rsunc0Eq+MV8UYICgn2 DHLP8HxsWjiTqDwOpxdHXt/gUcT33tnpkmWF+YtKYxsdJKFQq7GCA3942trBjm19N8 /taG2iuEYzP4vgcD+YuryfApu1ijzfHoWtl8LIF55gFLsjNC10D0UMsrFWJD9psn61 n+W38tnK2hhNLZ/93IcvdfnskEbM2fDBJ7wzh1SGJTF7dvupS3I395I70Ei5C3wXO2 aAGqtsDFdVveQ== Date: Wed, 21 Oct 2026 13:31:32 +0100 From: "Lorenzo Stoakes (ARM)" To: "Gregory Price (Meta)" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, baoquan.he@linux.dev, baolin.wang@linux.alibaba.com, hannes@cmpxchg.org, david@kernel.org, mhocko@kernel.org, dave@stgolabs.net, roman.gushchin@linux.dev, stable@vger.kernel.org Subject: Re: [PATCH] mm/vmscan: reclaim every zone in per-node proactive reclaim Message-ID: References: <20261019185002.3428594-1-gourry@gourry.net> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261019185002.3428594-1-gourry@gourry.net> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 006A94000C X-Stat-Signature: cbcjsfxuenjqte8iqgrahyj1gxbdw37z X-Spam-Status: No, score=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1792585901-161145 X-HE-Meta: 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 4Wvf62sv rpGi8JTFTWvJF04Xu3cCoq/aG4TVAfhsJc8PcMlc93xrWm2HAFESh/ZX3DFA12foPNcOKDZ+7ximNxlMjWSfOfx5i/IdU1/Ekc/HQWGaCvEZgFrJ6629EUDUiWiwtu09wttay67UhpbhuLnffKeHc401M06wFeXxv86eD8h1oMhY4TV7q2DXH1p2iFhcqmHIO34RBlALHEKO/L1VKD3Fzd68lcqiGWJEwPPantXvPEXVJOYnXeG0EASTwipWiqT+smkaafF6UU6DbWNz9Vz4zybYfXG7prKsYKLcBSzp7hvtA0dehmnifj/DNh+gJAao5wnvPL+o8EQ6260UVPM6q46RQDg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Oct 19, 2026 at 02:50:02PM -0400, Gregory Price (Meta) wrote: > user_proactive_reclaim() limits per-node reclaim to > gfp_zone(GFP_KERNEL), which is ZONE_NORMAL. Proactive reclaim serves no > allocation, but that limit makes shrink_node() skip every ZONE_MOVABLE > folio, so writing to /sys/devices/system/node/nodeN/reclaim never > reclaims a node's movable memory. A movable-only node, such as dax/kmem > or hotplugged memory onlined movable, reclaims nothing and fails with > -EAGAIN. > > To reproduce, fill a movable-only node with clean page cache and write > 200M to its nodeN/reclaim: the write fails with -EAGAIN and the page > cache stays. The same write to a ZONE_NORMAL node frees 200MB. > > Scan every zone, as memory.reclaim does. > > Fixes: b980077899ea4 ("mm: introduce per-node proactive reclaim interface") > Cc: stable@vger.kernel.org > Signed-off-by: Gregory Price (Meta) Seems sensible to me, and since it's become the review of the ages (TM) let's try and get some kind of tag record here :P Acked-by: Lorenzo Stoakes (ARM) > --- > mm/vmscan.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index e82ba737c028d..90f7a7bf4e426 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -8180,7 +8180,7 @@ int user_proactive_reclaim(char *buf, > } else { > struct scan_control sc = { > .gfp_mask = current_gfp_context(gfp_mask), > - .reclaim_idx = gfp_zone(gfp_mask), > + .reclaim_idx = MAX_NR_ZONES - 1, > .proactive_swappiness = swappiness == -1 ? NULL : &swappiness, > .priority = DEF_PRIORITY, > .may_writepage = 1, > -- > 2.53.0-Meta > -- Cheers, Lorenzo