From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 385603242B1 for ; Sun, 12 Apr 2026 22:50:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776034259; cv=none; b=D+mvVBJQPy/UKrkx43ke0nzI+S2oogfaArgLeWkr34KG8MZGxS4SzjNLAxDHsQUEUyKP/w6KltrRn0TxMPVjBW4QnVxv1p74o86nQ/YD1gNJCUYed+UZNdbKCZhBzHDdiObIWxe4J0/rlIpZK/Wa5OBVZ1aLt4ycwv8aJTWNO1E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776034259; c=relaxed/simple; bh=3c1PROdbIMYmY2GV+qxQCYKAu2jqElfAQaiDsBAfyhY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pr3hy+1ct2emjWsQ/B6E/K6l0LpIM0yvrYtZ6wdLfZT/Ahf9HSP9O99MrOUfPn3HrNjWMtyEt9UlcK15vZnYRoqOrbyvE8c5ls/0we/hn7vADFGunIfDtpBKrhZJBZa6+V59WNOj1npMeJ1fflHEOLmRd7F9PTmN3q0RXbwJRNI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=IABUpWQw; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=rlMYtvHB; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IABUpWQw"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="rlMYtvHB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1776034257; 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=KFX8n0nPntDWisBxedrwOsXfOmZ1OSsMtUQjLyBO7ck=; b=IABUpWQw/lGVFgTh0ebihC5sWxM1hZ+twgt5Cz+J2OtGQQIKb/Edo+XsjX1cHX2V7tlfoy vCzqvBo94zIXKOFRuw0cPsqrYhdWaHMpIdRUNWwdkjLGkw99yIfG8cHZ2V3lYhu7ncF5DH Bd3xiIYDt2JLb/M3j8zd3RXAfkB/a5o= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-558-D-V-BiHyMMmwNkfVdhRnxg-1; Sun, 12 Apr 2026 18:50:56 -0400 X-MC-Unique: D-V-BiHyMMmwNkfVdhRnxg-1 X-Mimecast-MFC-AGG-ID: D-V-BiHyMMmwNkfVdhRnxg_1776034255 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-43d7757463eso179314f8f.0 for ; Sun, 12 Apr 2026 15:50:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1776034255; x=1776639055; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=KFX8n0nPntDWisBxedrwOsXfOmZ1OSsMtUQjLyBO7ck=; b=rlMYtvHBalBHp6PctH6cJaWCFS3Ynp1au9CaRiTF7a4beyCVunLA3kgNTYWySkY9dZ sTegZshRyKtTDSouEVZXJeVdNly+qzpyoeoXlYgtOqGFWSVVqP9TJsAWHc8i69Es8bk3 jB6bxfCmvWLHuCPB8UyyCF0anskF9GkATdDv5RFM2yQkxExrCrUH7g0gyL9WnIhpQRKp HOoD2AS86gDh0TsTLwIL4mcAtLuX+4fJmBCiCIFaZXhx1WSi0SgGwkig2ISlCeBZTrQc 30W5ObaZP7i+qjgemiJj/XxfEG4910iIxdA8ok/xNRfBwoL3+QRDzULHcq1eYEQUEL2+ 3tXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776034255; x=1776639055; 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=KFX8n0nPntDWisBxedrwOsXfOmZ1OSsMtUQjLyBO7ck=; b=ht9r4pwhCMV+QWT6WZdHg9wPHbk3ZQO0Rt4W5uZpblEBDX2GPXvV0VvUcY6sGJJ+bb 6oTk+kNTErRp3V/4kHCjhC/Kj6f5RHEvuWgOJaw2LJc2q7XGZNUnULIBwoPn/fikEFoq lB2mMbU8uFZosD8MH/L2Znr5Gwc7q97LJWybA2fp09IJ/hygtUX1xlqrMHAqBk8V2BMB zyJ6TlYKAt2XuvxkPj18VB4xksQUoa5aBBieGY4YIFmQWq5fwajNv842wxxUw5cgPknC wnXPzlmZ8nuYP9gTMOjPjKFx8AYRBqjx3TJGNVIGAeNYqIPYj6Mc9S8E5w/T+UHscLDx Qqkg== X-Gm-Message-State: AOJu0YxkjzdySWy73v5e6FDgUm91iVjZRR+9kec34LtnkSG17TPUNjdR yWKXYeJMA5SJ0aGPZ9PQGs6s4Wa7oSq4sYoAdluk1KZtOTGpXKIH/rxu3AUaycuaoK/H9ssjdl4 KAgOkfuY/VRwqvVEWY3611RbodWAND33dYrO+0As3yka11Z9xd0kM8feIq77SByDy2d62qTfSSh qyXCynZqM0Qr/f640V8629tiiHrdnmD2fH1lelmcuAqcE= X-Gm-Gg: AeBDieuwpIw48qJTVKY3hRUk4cTXaVlPyc2vJ6qAmYQokVuf+pjhrc32m7pYKTyuL0R 1bss8EWnKuuZ/eUGTtZsA6W6a2LkeoLzXdSuoSmekuAIQe0O/ZSrA3v91+9c+FuuXSZLK0pFuZF t2Q5FUu7IPGlWPt6V/rKPUVLBty5mxyMp1u5ANurI7L3aYG695z5SF57iPxtn2oqaUiRq3RuzdT 1duZa1Q4TLrEAxxe7OluRQodxqnwk5mrOk+TfTH2iySwA1nWvlj8Ek5JGvpQJCv24of7+BusMND VHyTSnTmCC5dRvN+8t/tNY8xGe6ufkW3DH4rDacA5EzvEUaVfaap+DxCPfHqatnrWkgQQStyF1n FiYnd4XcbzV2x42sKlwDAlNwDFWjF9ij0NqE0gndmUho= X-Received: by 2002:a5d:6e5e:0:b0:43c:f5d0:4f6a with SMTP id ffacd0b85a97d-43d595cd582mr15728280f8f.21.1776034254700; Sun, 12 Apr 2026 15:50:54 -0700 (PDT) X-Received: by 2002:a5d:6e5e:0:b0:43c:f5d0:4f6a with SMTP id ffacd0b85a97d-43d595cd582mr15728249f8f.21.1776034254149; Sun, 12 Apr 2026 15:50:54 -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-43d63dec27fsm27061714f8f.11.2026.04.12.15.50.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Apr 2026 15:50:52 -0700 (PDT) Date: Sun, 12 Apr 2026 18:50:50 -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 4/9] mm: skip zeroing in vma_alloc_zeroed_movable_folio for pre-zeroed pages Message-ID: <027a31beac698f90e76aa68ba6a6101ba60246d0.1776033771.git.mst@redhat.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent Use __GFP_PREZEROED and folio_test_clear_prezeroed() to skip clear_user_highpage() when the page is already zeroed. On x86, vma_alloc_zeroed_movable_folio is overridden by a macro that uses __GFP_ZERO directly, so this change has no effect there. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 --- include/linux/highmem.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index af03db851a1d..b649e7e315f4 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -322,8 +322,10 @@ struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma, { struct folio *folio; - folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr); - if (folio && user_alloc_needs_zeroing()) + folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_PREZEROED, + 0, vma, vaddr); + if (folio && user_alloc_needs_zeroing() && + !folio_test_clear_prezeroed(folio)) clear_user_highpage(&folio->page, vaddr); return folio; -- MST