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 02902606A31B for ; Sun, 25 Oct 2026 21:49:12 +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=gWkUhUFU Received: by kanga.kvack.org (Postfix) id 0F8766B05B0; Sun, 25 Oct 2026 17:49:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0A95B6B05B1; Sun, 25 Oct 2026 17:49:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F057B6B05B2; Sun, 25 Oct 2026 17:49:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id D0A1D6B05B0 for ; Sun, 25 Oct 2026 17:49:10 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 2A2F41C0F79 for ; Sun, 25 Oct 2026 21:48:52 +0000 (UTC) X-FDA: 85362488904.19.E484F6A Received: from mta1.migadu.com (out-240.mta1.migadu.com [95.215.58.240]) by imf07.hostedemail.com (Postfix) with ESMTP id F3EFF40003 for ; Sun, 25 Oct 2026 21:48:49 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gWkUhUFU; spf=pass (imf07.hostedemail.com: domain of nico.pache@linux.dev designates 95.215.58.240 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=1792964930; 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=7wQNgAvrV53M6g73xXbn+Hsa5Wpgb9uHDA2CEi88MY8=; b=yot9ZgM260pw+zW/NKnHn5AAPU9pBn60GSc4UwfeKEIDEypNcvHcij/wuApuvnNyb2O0AO 8yom8qqQBM0AvJwiOdYy+WoKPVQqXM0ZBOK1zdfjdS1e+YyUvIS9062kVozQNF5ZNsaZ9Q ldg/nLOnj30RCntAUzTCCXPPqEniUGE= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1792964930; b=zLE+LIbKhWoztDegDJOySOyk4XV3FjihaT7ii54LjPnefjZbWoCJNRjGmfi7GtrXqwScT5 d8VRX+/YuM2U31Av4Z8PdGBXg4woUTVQcSSi8yrVm6VfBTxWOvhdpSAjGVKBQS7YOqM23f mOANHaDSZLoD2F+Rpjzhe/YKYGjGZIg= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=gWkUhUFU; spf=pass (imf07.hostedemail.com: domain of nico.pache@linux.dev designates 95.215.58.240 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=FW93I9g2tFhlVSvMbZvJhIsiJI9bo4PZOSNREMcmxDA=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792964928; v=1; x=1793569728; b=gWkUhUFUyP2n9w1XqfxuzV06+ZqN3YN+wNJCYBrB4HxP5Nwf4YoA/Ifr7LPlYyKV633fnYzN ZQA0k94WlZsm0a64RNpARKHYrHVnMTF+ivYvmRNLgLaeOBang+tBO6hINmNWwGhQVq7MrwtftlD 8ilzZwtbnrH9kXJ2kDI26e2M= X-Envelope-To: linux-mm@kvack.org Received: by smtp.migadu.com with ESMTPS id e5eed0b9c945e22a; Sun, 25 Oct 2026 21:48:48 +0000 X-Mizu-Trace-ID: e5eed0b9c945e22a X-Migadu-Flow: FLOW_OUT Message-ID: Date: Sun, 25 Oct 2026 15:48:43 -0600 X-Archived-By: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/2] mm/huge_memory.c: skip zero-page remapping when underused THP shrinker is disabled To: Barry Song Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , David Hildenbrand , Zi Yan , Baolin Wang , "Liam R. Howlett" , Ryan Roberts , Dev Jain , 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 References: <20261025-b4-ksm_fixv2-v2-0-8b61ad0491f1@linux.dev> <20261025-b4-ksm_fixv2-v2-1-8b61ad0491f1@linux.dev> Content-Language: en-US From: Nico Pache In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: F3EFF40003 X-Stat-Signature: wdto4kgutbjirhypghw41sgcnqozbzjd X-Rspam-User: X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1792964929-41254 X-HE-Meta: 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 fOc+xY1A fugF2FSdpn4V/WXxnKS6jRi0SG/y841CjJYwm6Gyu/MCb7rjt8XgueAUlHhB8f/mstm/UCPPpRVy6PuUeV45fS/okGPH8wnKl8N5zFO+s/aAgJPSXVoBSBnrhYNVTBCRvxXtn6I/vsU6Lb0vuBUhR7Q9LczYKv0BAKpKkBVRrPNIkwJ5NMnS1YPaIVPgf/AUw5mjrGgPQudYBAh80vJp6R2vlbJ07PhPifZhN8SkjWcGFBX+rAV44SyUHnmB8UYpGqghmPoZ7zfbL0/jNfcWv+QvhRCwOVvQ5k7iANqzAl52Slk649wQvxqLLj58BKZxqu8nNQSiFdqrNhwFp5794TwohTra8KIroT4e1/C+juC/c+coA2c9gQJBt4xQ/XA3mrIt3XAI00f9RArt4/57ZWBvLRhcCeQFNwz2njVq63flrIykI3T6kFJUgEBm/xTEEwUzp 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 10/25/26 2:28 PM, Barry Song wrote: > On Mon, Oct 26, 2026 at 1:40 AM Nico Pache (Red Hat) > wrote: >> >> 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 > > is b1f202060afe a correct fixes tag? as > commit b1f202060afe has no even "split_underused_thp" there. I believe so. IIUC these two series were merged together. While 81d3ff3c6f7 introduces the toggle, b1f202060afe is where the behavior started. I guess you could argue that the Fixes should include both? Not entirely sure! -- Nico > > it was introduced by 81d3ff3c6f7 ("mm: add sysfs entry to disable > splitting underused THPs").