From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DD567E93807 for ; Sun, 12 Apr 2026 22:51:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 538BA6B0096; Sun, 12 Apr 2026 18:51:04 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 510386B0098; Sun, 12 Apr 2026 18:51:04 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 426EA6B0099; Sun, 12 Apr 2026 18:51:04 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 308EA6B0096 for ; Sun, 12 Apr 2026 18:51:04 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id B93218CE74 for ; Sun, 12 Apr 2026 22:51:03 +0000 (UTC) X-FDA: 84651400806.24.67E2856 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf11.hostedemail.com (Postfix) with ESMTP id 88FDE40003 for ; Sun, 12 Apr 2026 22:51:01 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=HvMhdOti; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf11.hostedemail.com: domain of mst@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=mst@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776034261; a=rsa-sha256; cv=none; b=bDJg5R8bXAX+zVL7vQkfn6Xq85vs20HAo3733vPXK9737PIbWVcsrLLgqyemcoVUdEkGYV WwBWMNo00dd03/+k7kF/EPMiiSh/jznS15ruwNQXvVuQ5/Yppx8cKTxJCyYuuX9ggB4QyU IRA8PFjnEHFu9qTwjI/zc9htvNm9oig= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=HvMhdOti; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf11.hostedemail.com: domain of mst@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=mst@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776034261; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ZObZy/vetFZ/0CGX/0sKWeCj7TXTkOR8AcV2oS2lySk=; b=3wEfw4l8NQUNq1FCZqjpRYhuML2DfTMRKa3OYajefNl9gpCFdYtOV6IpejfM0SI8LRJZ95 2zOt3JarR0Z7bFE2fmwdbZVtnqHVI+LR75CHCKLj3wiJgo1jAlv/e62QWvYcCYLkvfcRK2 8pDvravQqMHSrWKdQr7o5fRTfSyiWPQ= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1776034260; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ZObZy/vetFZ/0CGX/0sKWeCj7TXTkOR8AcV2oS2lySk=; b=HvMhdOtibyxBwhAWHaNAFk3A6aBGnH/GzAku+k13qfIPXWWrFxxd6xPEQXzlOcmTQPyyQb BV8TRHzxYkSwWzdbf/hCNVXOJxfCWPlx2t0f54LexKCFugm9clGyG1aWKAvD676rfWjA66 NOYkxl2XlWx1zlBZ4kecp6ADBn5E9/o= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-564-LAK4itmyMbSuQwZXmwpB4A-1; Sun, 12 Apr 2026 18:50:59 -0400 X-MC-Unique: LAK4itmyMbSuQwZXmwpB4A-1 X-Mimecast-MFC-AGG-ID: LAK4itmyMbSuQwZXmwpB4A_1776034258 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-43d6d0abbeeso826907f8f.3 for ; Sun, 12 Apr 2026 15:50:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776034258; x=1776639058; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ZObZy/vetFZ/0CGX/0sKWeCj7TXTkOR8AcV2oS2lySk=; b=RE0xliTttpEs2VSV0XhAOU2fSF4SSriG0S8cDtwT2mEQbZ/k8d9saXj/QAviSklFOV lTybfBoxfmW7AhGyitaB0g5gldt8iFt+xbs0khfmJBFiSywM9ppogLREQvpiXe8gZua9 Q7zC2/kHnTFFtC+hjsiOfBwW6uNt9g3VlvFaeXJEdNDghr/JP0uSV1WZbhYeTNzJMbhI cyy7JSrf/T4EKsEBX/ZWP4RoocD+sxb72ea0T8x0BR3DK6rMGYqSTAARCRx0lS4Nlb70 w+FKPH4sburD557EO/Wghzg8D5n4rmWAjYJQDFq3Ly6W6EXlVVKtksgm3abXO/stTQFt TjwA== X-Forwarded-Encrypted: i=1; AFNElJ/IndUtebOMsmQBuTFKQy9afQY9O1RYOS4hw6wxYSNZ5aI4xL8dwh4w3yV5p0rQ7ueUApG/lHnX4w==@kvack.org X-Gm-Message-State: AOJu0YxGM3Qj/uYQcQkee7sYgSZe68LmZ//OFUgGB4KgdxlRWMkfWsyE V+lqZud5zRFzPR5vCm/dIHGyq3u2BpKLPDxTtgVMSctZugLPWP2ibFcp7hf6VQybT36gDMhe5xY tTNFHlQWVEELDSoYmfXrknGdrJTwI0ZC0VDxvau07adJNro1FLK7Y X-Gm-Gg: AeBDiesBr1gXOcM1kVoD0iqm000SHYq871aFZvq1zxRMCErc82qZprzLAzHHOMyS+Q1 uGgnfOacdY/pQUaq7CYI+8MZ4IbK1UrQquAEjasmmVlSTwT8acyFpbR5Lfnk4tmOtg0sm5DLXBc F2hB//4hdOtIFlU1ln4lpbva9keuazAZus50z0kRk3m7BGc4RODM34y3hCpbx+H1F8OrTbH1hL0 7HpT5kNpxvOcmCtV+ztXUKiwJ1TB7m7mTcRVqt/RRIwzm1bgnt4PE/xvsoNzfo782fkIV4N8whr 91oDBwep85LDkPVvvn41MEk39vVCGhfzDRzpJqtPWawQWiimzvaPQ06aiyVC2fQpMuaVQQSW+tz 3VlleiM1d0QytyGsbIvmlzzv51zRGX4SU8MnF7a/WxPQ= X-Received: by 2002:a05:6000:250f:b0:43d:1c7a:8b5b with SMTP id ffacd0b85a97d-43d642d1d00mr16517155f8f.40.1776034258040; Sun, 12 Apr 2026 15:50:58 -0700 (PDT) X-Received: by 2002:a05:6000:250f:b0:43d:1c7a:8b5b with SMTP id ffacd0b85a97d-43d642d1d00mr16517133f8f.40.1776034257540; Sun, 12 Apr 2026 15:50:57 -0700 (PDT) Received: from redhat.com (IGLD-80-230-25-21.inter.net.il. [80.230.25.21]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43d7400708dsm9145343f8f.25.2026.04.12.15.50.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Apr 2026 15:50:56 -0700 (PDT) Date: Sun, 12 Apr 2026 18:50:54 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Andrew Morton , David Hildenbrand , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , linux-mm@kvack.org, virtualization@lists.linux.dev, Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport Subject: [PATCH RFC 5/9] mm: skip zeroing in alloc_anon_folio for pre-zeroed pages Message-ID: <56ae30d7f080b089e4fdc93c4d6e2353a9e0123a.1776033771.git.mst@redhat.com> References: MIME-Version: 1.0 In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: a-jZxyGHiCSuznza2X1KbjzVWByZmcBpoPtmAfxCDSU_1776034258 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Queue-Id: 88FDE40003 X-Stat-Signature: 5a1fptekfd16qhwdpbo77ys9uiorbb5s X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1776034261-897490 X-HE-Meta: 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 WDa/s7KG qi8SXD2w+J7QM9LMVdEq23+IY+XqtQOrJNShlal386uj1a9YlQVSD4+aygw69oW8l2RLOF7FezBh10APB2eBYnYSzCkLXkqMlv83eF+LifRbrt5tk1A3dbj7FCXRr3W5fmuTNzdAPanwOIIiuvh+JVkm4o1GZzfZu6zga+zH+YoOU3JF/Nu7QCKrBy8j4OekcIlzHu95FccSXtmeyRqwJhmyF57ZqyqntT7uQft4x7LiSvp+imFiSBFsyKtz98bbUyBlEoVhABp3WpJmZV52Wv2eGOAQBVbuEhEvw+ak/uZLfSnNNf9BGRZueI0t895gcmUoUoaZnjzpVUKV/BeLFkHUzxG5pBX7t6LauFNVWuWJKyLSC23UnRBzHvw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Use __GFP_PREZEROED and folio_test_clear_prezeroed() to skip folio_zero_user() in the mTHP anonymous page allocation path when the page is already zeroed. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 --- mm/memory.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 07778814b4a8..2f61321a81fd 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5176,7 +5176,7 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf) goto fallback; /* Try allocating the highest of the remaining orders. */ - gfp = vma_thp_gfp_mask(vma); + gfp = vma_thp_gfp_mask(vma) | __GFP_PREZEROED; while (orders) { addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order); folio = vma_alloc_folio(gfp, order, vma, addr); @@ -5194,7 +5194,8 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf) * that the page corresponding to the faulting address * will be hot in the cache after zeroing. */ - if (user_alloc_needs_zeroing()) + if (user_alloc_needs_zeroing() && + !folio_test_clear_prezeroed(folio)) folio_zero_user(folio, vmf->address); return folio; } -- MST