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 525E0F588C2 for ; Mon, 20 Apr 2026 12:51:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 793246B00A2; Mon, 20 Apr 2026 08:51:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7451E6B00A3; Mon, 20 Apr 2026 08:51:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 60B846B00A4; Mon, 20 Apr 2026 08:51:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 53C4E6B00A2 for ; Mon, 20 Apr 2026 08:51:07 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 04D508C8F2 for ; Mon, 20 Apr 2026 12:51:06 +0000 (UTC) X-FDA: 84678919374.21.1A58944 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf09.hostedemail.com (Postfix) with ESMTP id BBA84140002 for ; Mon, 20 Apr 2026 12:51:04 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="YiNQSON/"; spf=pass (imf09.hostedemail.com: domain of mst@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=mst@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776689464; 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=qAGKc42yexqH1EWWUAUEJrDKNbSbrVhgetE1tPIVhxk=; b=dsoQz/T2fz25Fbc1c/r761taZvT5qef7bF77Ib5EbfpTvBY9FVfs0IbQE/Dn/EEPla4HiG fZDI40j4YlhvV91qBGgC4iIa3HRLyRqaVeZjwAWBPxHljE6GVipbdrcltIdUvzXhA/h461 k4l3wrUjav3igCzfa3tPstCAEkNWmy4= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="YiNQSON/"; spf=pass (imf09.hostedemail.com: domain of mst@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=mst@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776689464; a=rsa-sha256; cv=none; b=UlphxMs8RnmCCL3v51cU7xKbj/SNNiDlxXTC3XgzNLNmGqqhjhpCVtTb4s6treJ/oUht83 aQhBFhno452Gld8JACR7WPMwZs+mZYjx3b9S0pABQnNbCTH1Yf7CempyGv3eKfL0ZBqlrK u6ysNrWFPuzEEKdKe9uxBObp5bqSqPk= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1776689464; 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=qAGKc42yexqH1EWWUAUEJrDKNbSbrVhgetE1tPIVhxk=; b=YiNQSON/8g87eryTeEMV5boZNvDQ4wLJJnMCCbXmvA2e7/T8Jz0KnRh6PjKyXgOkwX3aXc D6FPwSCxdjcyIXaD42Tqsf83dxV2TUmN51c4mzu8dkg3PP7u2npaqZfDbZIq9gQ+RriQDa hEND9dGdjgWJ5o6BLnb5bXnCkwoD8w0= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-483-7d7MWAHvN5yB8HTrx5kIlg-1; Mon, 20 Apr 2026 08:51:02 -0400 X-MC-Unique: 7d7MWAHvN5yB8HTrx5kIlg-1 X-Mimecast-MFC-AGG-ID: 7d7MWAHvN5yB8HTrx5kIlg_1776689462 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-4891f97aef0so3768855e9.2 for ; Mon, 20 Apr 2026 05:51:02 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776689461; x=1777294261; 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=qAGKc42yexqH1EWWUAUEJrDKNbSbrVhgetE1tPIVhxk=; b=ITZ9KxAOh7pu58NPUe29I9nlD+pnJX+j/oITId1blqJBbSJgNBmnFoF8QNWMGnJa9K rgmwiLA3LYjuWReYMOwFu9nMsjGffUz1cJsGIGdLskhL1IHa+thbQzTpdIQdwVqk0sjx KmkZpTONoOI1corW5+GCsXZ0/S0yKN2U7so4AEDVLH1Dhay3bsL8Iiqa/RDG5qTI8Nua 3oJ+EsypZpjZx24+2/nKRAwllluGAZFvQmGyH2qGL/gMhUd3inm6IAjhjZlV4K6Jq1z3 k1h02cBLaf0m+w4x1S6wxf7i4IL/wLtAEUN21XtYqX8YWjtrZU8sbukRdflxob34eSA5 rvvA== X-Forwarded-Encrypted: i=1; AFNElJ+hDacg1YAcJNutEUXYwgcLuzTJ5ZVnzcsCtV9EIYJ/ZWz82hzLTlNDNFPyw+jrz+tg+kgqu0EldQ==@kvack.org X-Gm-Message-State: AOJu0Yy45Vlf0fbCP1gsVpX2OcU1t9uy5IZ1iNQ1kC56PTVAM5PW3aU7 foJx8ZeaH6wu91DzSKVHCrj21tCm3XS+4wsPat1Lwk6/cki3WvTet3ByicjdJb2BU+n+G1zcg2A K5KQ3Rwi4xnDF0gOk/UV1UbLWx9eF2PBVirlHlA19It1m8hAqQsDj X-Gm-Gg: AeBDieuLheJrASWAYV0upNpmpeHlFqEwu+uPEEVYmaRRRsE2UO/ZW0MbdRJQI2PKZLk WxXuAz64erh7zlZtnS1rAhwyN8fohVoJwykBMT0X09JgFh3AhsggAiyrX2BHPpa0q0LHmJ72pi6 C4sfMhaBHrLXZu4LJZDYogzfVJ0Vs+JQ/h4lyWQczcTSy81XVy8i0o4Gl/Fz+HhryVP1fUeiwSb f1BGFUliQg9la34hjc6t4YzAdVv0TIB99SjXLD7pTon15WIjtPY4zn6eccEFSwgvBoh5E/xs3Uh azFRaYvcCiw1xIXQCKHAZByVWN7fplMU24MRAoJY8A24r35LuWkGHYyGKqYPSF2VVPd6ApM7po9 45ryKpTF1GkyGZ7SJ2znl30+pQczXa7etd5kGAiO2tBPqKxm06HDOdw== X-Received: by 2002:a05:600c:a00f:b0:486:fe83:8621 with SMTP id 5b1f17b1804b1-488fb788924mr200859375e9.23.1776689461535; Mon, 20 Apr 2026 05:51:01 -0700 (PDT) X-Received: by 2002:a05:600c:a00f:b0:486:fe83:8621 with SMTP id 5b1f17b1804b1-488fb788924mr200858775e9.23.1776689460975; Mon, 20 Apr 2026 05:51:00 -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 5b1f17b1804b1-488fb735d3dsm184142605e9.2.2026.04.20.05.50.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2026 05:51:00 -0700 (PDT) Date: Mon, 20 Apr 2026 08:50:58 -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, Hugh Dickins , Baolin Wang Subject: [PATCH RFC v2 14/18] mm: memfd: skip zeroing for pre-zeroed hugetlb pages Message-ID: <03405f0008afd371021e98a985490dce7fab6e7d.1776689093.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: unCxiB0-i7YMBS6k5iM8NepmcmCH6n6mfnLu9NecCWs_1776689462 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Stat-Signature: d4npksjqydut514t9ra3ssf8gpbjzrsx X-Rspamd-Queue-Id: BBA84140002 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1776689464-975855 X-HE-Meta: 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 P6yRw2Nr Z2lDI7R2zDEePI1tlkrMhd7eABBfXdJ6ilBfTX0RLgwu+DynnWnnX2y5UsjwqSZ2tikA3awfnfjGlsgxd3Al/YhdPBFLhNLKEbWgYwHQDD+2VPJXjo2M+a7U64j4PntoY+aPrhhxSDto8DAsjxc+jbchffzbqhZS9mVayouFyUQomEe2l2weblPsTHWoUMal3vcrrnBoCp3mfxQX92R6yVPRieGcj6Ortt9O/uJHo7nb7z4v/RhXgl94MQFkCgi6r+SoSLf5AvBrfsIel0eMZBeKo67XFDiUyh7xD4Q9eb0482MiN0Kl+KmcMpmuRMOJ8gxYY Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Use the pghint_t output from alloc_hugetlb_folio_reserve() to skip folio_zero_user() when the page is already zeroed. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- mm/memfd.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/mm/memfd.c b/mm/memfd.c index f1c00600e19a..546149897369 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -81,6 +81,7 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx) struct hstate *h = hstate_file(memfd); int err = -ENOMEM; long nr_resv; + pghint_t hints; gfp_mask = htlb_alloc_mask(h); gfp_mask &= ~(__GFP_HIGHMEM | __GFP_MOVABLE); @@ -93,17 +94,12 @@ struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx) folio = alloc_hugetlb_folio_reserve(h, numa_node_id(), NULL, - gfp_mask, NULL); + gfp_mask, &hints); if (folio) { u32 hash; - /* - * Zero the folio to prevent information leaks to userspace. - * Use folio_zero_user() which is optimized for huge/gigantic - * pages. Pass 0 as addr_hint since this is not a faulting path - * and we don't have a user virtual address yet. - */ - folio_zero_user(folio, 0); + if (!(hints & PGHINT_ZEROED)) + folio_zero_user(folio, 0); /* * Mark the folio uptodate before adding to page cache, -- MST