From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.202 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792950046; b=Jhu4AGHfJkacyXW6gJd1ymHcBXqUi8kp+S0tAId6T0pxjjbPZE8kQgwNseY/D2hqHGAC GJLdzl4ke2NQpDltmpeiTM4pvNe5O5x4PexzOdGGLKSORJ4n6jXqigfpABWfPwg8h++mp 8Eceq1+OeNUVwftd+VmSQFblI4SA1O5Gt5I2C6YEbUd+KkRK1KlMB4HG03RFx7URf4PIu QX7JhDf+2coAv6ufRGmcvHNozrdNnwOtivaoHEPTi/94o8Y5+9aE0AEHyU9ewW8BOWfDh CP4vSdooD94+rd/gEaHoaGQ7XlkG3n78Vtv4nAxqQE97YXALb6ajYOv9f6Zv8KqwGLg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792950046; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:Date:Subject:MIME-Version: Content-Type:Content-Transfer-Encoding:Message-Id:References: In-Reply-To:To:Cc:X-Mailer; bh=wx7DtEnW/yiqV2jfL4jW638vppvg9yzl2vShHqhjnzQ=; b=LTk0OFkWGliz6Csxv+1jwW1qV0zz05nGSg8lpZj0M83P92AV7Oj+GUlFWuZQVW/gh5Y5 hdazO+dqswQHhdY0LIbUBQoricLQD1G1HP5P6zwMftVLtPAG/hJLNDop7QOHOAVPKfEq3 g5fSNC09X4YCIzPbHL0dgHn+J/YgXtirOKOZDebMF9gtOmtt7HzWLfaC3GEoHXN25cHZ8 DakVWq9SebdWtVzIhbZZIDwv3sMsPYiP4803rvzR3TYvqSIwmMjGx7kWKESkohi4AF1oF Jg5VyXEL3tkOnbLkY+lut8a6o9vZoxwUrKB9le2NDElxHooxxOEJWYh7hQUAWoKb1TA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=gT796LRL; arc=none smtp.remote-ip=91.218.175.202 Received: from mta0.migadu.com (out-202.mta0.migadu.com [91.218.175.202]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81C23606A32F for ; Sun, 25 Oct 2026 17:40:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 81C23606A32F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev 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 X-Envelope-To: linux-kernel@vger.kernel.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-kernel@vger.kernel.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-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-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 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