From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7403B606A31D for ; Sun, 25 Oct 2026 17:41:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=gT796LRL Received: by kanga.kvack.org (Postfix) id 178CE6B05BE; Sun, 25 Oct 2026 13:40:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1064F6B05BF; Sun, 25 Oct 2026 13:40:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EE7576B05C0; Sun, 25 Oct 2026 13:40:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id B74E86B05BE for ; Sun, 25 Oct 2026 13:40:46 -0400 (EDT) Received: from smtpin23.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 367C7140591 for ; Sun, 25 Oct 2026 17:40:46 +0000 (UTC) X-FDA: 85361863692.23.FCA1374 Received: from mta1.migadu.com (out-121.mta1.migadu.com [95.215.58.121]) by imf17.hostedemail.com (Postfix) with ESMTP id 009B640009 for ; Sun, 25 Oct 2026 17:40:43 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gT796LRL; spf=pass (imf17.hostedemail.com: domain of nico.pache@linux.dev designates 95.215.58.121 as permitted sender) smtp.mailfrom=nico.pache@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1792950044; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=wx7DtEnW/yiqV2jfL4jW638vppvg9yzl2vShHqhjnzQ=; b=RuY7Q7lpdK4AyKm5sWinZB7zH2NOw8rR0xgBfAhkOxUeZc7Sq27ZeS1IHdeJFMyQuz/jsb rOWXTfCY3iJCqeBwuwotrHN4IclStWnpZV2g0/ob+tE5gUqvmcknTmDmiBRyRiCZSkdwpv 1hSyt5YtKztxxseA7+Uwk2krr8NSqSI= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1792950044; b=Bc6u3pzzptgHl37W5LiHdesPXqfKwgK9Dri3o+h24Fe400GAfAjxKv0EvuDf/32TjHH3IL tz4jtzHtgx5vytxs9mVjcdxd7Bj/4WLJOY1yZ1Jn2z1GIik9e/k8kLRouuZZZcPafdGadO s/HFr+/TCwPEFtyAj0ikHQrdCTihLVM= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gT796LRL; spf=pass (imf17.hostedemail.com: domain of nico.pache@linux.dev designates 95.215.58.121 as permitted sender) smtp.mailfrom=nico.pache@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Envelope-To: linux-mm@kvack.org DKIM-Signature: a=rsa-sha256; bh=OWOq7n51OZNlSYTiLRU59Gz0Q2na9qpH+zMvubZiDBc=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792950042; v=1; x=1793554842; b=gT796LRLwsqHeKK5Gm1O7PXv7PjYZqZnGEQMo1b1BHHXGFRMX8GbgNDe3JAvxpKb1GxwTyLb kYgsYOtk/zUQWTCTpbRQnsMTzudDk4Qvmr7mfH71BESGSTl5FjvhQL4vGfWUspQw0BK1vrOoKCY x+IthNE1nY9xE5RZ1bLust68= X-Envelope-To: linux-mm@kvack.org Received: by mta10.migadu.com with ESMTPS id 75892baac6524e44; Sun, 25 Oct 2026 17:40:42 +0000 X-Mizu-Trace-ID: 75892baac6524e44 X-Migadu-Flow: FLOW_OUT From: "Nico Pache (Red Hat)" Date: Sun, 25 Oct 2026 11:39:46 -0600 Subject: [PATCH v2 1/2] mm/huge_memory.c: skip zero-page remapping when underused THP shrinker is disabled X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261025-b4-ksm_fixv2-v2-1-8b61ad0491f1@linux.dev> References: <20261025-b4-ksm_fixv2-v2-0-8b61ad0491f1@linux.dev> In-Reply-To: <20261025-b4-ksm_fixv2-v2-0-8b61ad0491f1@linux.dev> To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Andrew Morton , David Hildenbrand , Zi Yan , Baolin Wang , "Liam R. Howlett" , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Yu Zhao , Xu Xin , Chengming Zhou , Matthew Brost , Joshua Hahn , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Usama Arif , aarcange@redhat.com, "Nico Pache (Red Hat)" X-Mailer: b4 0.17-dev X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 009B640009 X-Stat-Signature: 1b6mdai5cy1tbpah8k4taqeb85waxxio X-Rspam-User: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1792950043-297587 X-HE-Meta: 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 CfNpbvLi E6PjHneBRCi4/L3gJpySSZChKI6JH05DE3vGnhBmGFBlkdpSTLxxenNeB35ve0Aj7iCnPxuJSouUrNT/MvtHD1VW8eYB1mZaxb6NheV1KRimK4ikNwVUuQgw8aBX9Dc8kF4mIzdsgujXqkhsVIJyiHC8CpfRFrthfTgFVqmL+xgazxqqFMKUg4dwRlNsVSTp5lHor8b+tRqpnJXLqmBiQ7AX6zn9grflDBDLvGilQHLKU1+BodkkdwhGAp8ipSwPXX8+b5rCpWR6QhbnWNvmM9KdMmEz7KS2S9BhfmalO1PXvx7KLxoRB124Ev65qZLWGcy5hpozk7Heq8IcPSZiLifYVDPHnOWdCConTIkE8kHl8B9s495cA4vGnMTYnVwk8ry4g 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 The zero-page remapping in __folio_split() was added to support the underused THP shrinker. When the shrinker is disabled via shrink_underused, gate TTU_USE_SHARED_ZEROPAGE on split_underused_thp to avoid scanning subpages for zero content unnecessarily. Suggested-by: David Hildenbrand Fixes: b1f202060afe ("mm: remap unused subpages to shared zeropage when splitting isolated thp") Signed-off-by: Nico Pache --- mm/huge_memory.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bd44d58e8684..2d56d1bff0ea 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -4104,7 +4104,8 @@ static int __folio_freeze_split_anon(struct folio *folio, out_no_split: local_irq_enable(); if (anon_vma) { - if (!ret && !folio_is_device_private(folio)) + if (!ret && !folio_is_device_private(folio) && + split_underused_thp) ttu_flags = TTU_USE_SHARED_ZEROPAGE; remap_anon_folio(folio, 1 << old_order, ttu_flags); } -- 2.56.0