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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8071AC46467 for ; Thu, 5 Jan 2023 01:50:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0FCE28E0002; Wed, 4 Jan 2023 20:50:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0AD338E0001; Wed, 4 Jan 2023 20:50:59 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EB6FF8E0002; Wed, 4 Jan 2023 20:50:58 -0500 (EST) 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 D87F38E0001 for ; Wed, 4 Jan 2023 20:50:58 -0500 (EST) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id ABB11A0167 for ; Thu, 5 Jan 2023 01:50:58 +0000 (UTC) X-FDA: 80319066996.14.A95FC2A Received: from mail-wm1-f47.google.com (mail-wm1-f47.google.com [209.85.128.47]) by imf15.hostedemail.com (Postfix) with ESMTP id 212FCA0002 for ; Thu, 5 Jan 2023 01:50:56 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=Qok5PnDt; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf15.hostedemail.com: domain of jthoughton@google.com designates 209.85.128.47 as permitted sender) smtp.mailfrom=jthoughton@google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1672883457; 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=yqfl4xJm+Wld0bPquuUz0o/yojxexveabYMG4JIRCRw=; b=ifaVeQXtVlpg7pJ63MVOUvvMGz3d50ourPpTHpclEaJwa5LwOuQRcIdB3KmHKE2fy8jwJ4 AOaOMHc4nDoh5YGTR6O8xt1ltm7dkpengfCPGooAS1359KY9RdEuB9hz5xw+vZ0GsFUwGj Hzc5fk/kmRUWZiOyGGjjnwCXjc79IVo= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=Qok5PnDt; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf15.hostedemail.com: domain of jthoughton@google.com designates 209.85.128.47 as permitted sender) smtp.mailfrom=jthoughton@google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1672883457; a=rsa-sha256; cv=none; b=Nq0gZ3i8YZi6ADJqCZbPv8FOzqvyMxE5D/i2MzP6JFPjrPZEwzaMNTS2CYXY/FSheHzN4s ulMOtDwdndskoHNVVqYOOZMadPjTDC6+hB2/XRn/hyAI/ewWCgwgJM5kDdtd23VWPZvAVH FM+IhYch8wt0j3rbixtMbLm5ax1c++U= Received: by mail-wm1-f47.google.com with SMTP id m8-20020a05600c3b0800b003d96f801c48so294046wms.0 for ; Wed, 04 Jan 2023 17:50:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=yqfl4xJm+Wld0bPquuUz0o/yojxexveabYMG4JIRCRw=; b=Qok5PnDts10sjUXsNh9QcIsGF42bksh+y/PzDySJHxG0qPjMJGnjJu0D2IBu9Ljw0S bKWr6Oqgz24nXkftP02bkHPGE8PGfIlchPKVTQnioZ97vJ913mBvaoPzir/3gmdnj6S6 p0ml9kjP1sgAvonF5uWIf39mt9iE4GT9DeJ4WxTIHqdXOXm6zVA8Y4SKKWQ3qHgdfGJ6 6yGt7L2qZyt+ECDwFtr8DARAUHVnH2qTtZKmiwW33+gJILmfie2jXi7MtqyWDrpEpz0k sS6J6yd414UxQsb2UE8WdLl74rUmPEEv7VskJ2+2+kzkNqcLSXHpt/wxBVa0neVubM2o SQQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=yqfl4xJm+Wld0bPquuUz0o/yojxexveabYMG4JIRCRw=; b=p4gFM/4JwWDMQTe8t/3WOQxuLbUlFt9dovb6q6/zWwQ8xseLNJaKLzedh8jV38oUer xon5uQrg9LpJHaQQRXcZccOLJMRiJ1y81TGSRa1TPRnpe9yTDmgA/1GCQ+VlPG5kU3XW aHgn+G6NtZ8iI+9JlXj84Xe464vMZTraonkD1E22Ta/zEu7BwrTItg0EG6oWjImuehOx PZ0WydBg4eM8QpbQ20zIbhsTDZDymD0SyquPSBGaqd/tM7W03M7Gsb6BXz7DLzT4C65C nOEOSqVeZjxImfsHIXr9wA/N7HRDmMwTRTqS8xiZ7lFdp4noTYo10gIpRd4BnS78We6W +F2g== X-Gm-Message-State: AFqh2krc5Fo3ugzoymC8yKMXuULnC+sYKCEP7F/8tPEpS618GkqcNIbP EQ0UvlzXHQZxZ/tIb4JXM73DwC6FeUdrG5Answ1lTg== X-Google-Smtp-Source: AMrXdXtg7ahs4squVQDsseVSKq1N8Am3Wh9SCbdeRbHyzAK0hNiDqhlUbY8czXt2TEKWbAPu6YgC6GQxpY54u1pUQ9k= X-Received: by 2002:a05:600c:4b95:b0:3d1:da8c:7869 with SMTP id e21-20020a05600c4b9500b003d1da8c7869mr2632215wmp.26.1672883455586; Wed, 04 Jan 2023 17:50:55 -0800 (PST) MIME-Version: 1.0 References: <20230104225207.1066932-1-peterx@redhat.com> <20230104225207.1066932-2-peterx@redhat.com> In-Reply-To: <20230104225207.1066932-2-peterx@redhat.com> From: James Houghton Date: Thu, 5 Jan 2023 01:50:42 +0000 Message-ID: Subject: Re: [PATCH 1/3] mm/hugetlb: Pre-allocate pgtable pages for uffd wr-protects To: Peter Xu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Mike Kravetz , Muchun Song , Nadav Amit , Andrea Arcangeli , David Hildenbrand , Axel Rasmussen , Andrew Morton , linux-stable Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 212FCA0002 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: p73hmp5udyo1pkenkbbnec4i1a5iys5k X-HE-Tag: 1672883456-200417 X-HE-Meta: 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 2OL6yeKD 0heKABoYLxlKas6iQ+QSsiK+925tTQyv7nr0tjQtwYBossneVYePjdu0Ef9wZEbMdeWpc/3O4XjGZSgg= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jan 4, 2023 at 10:52 PM Peter Xu wrote: > > Userfaultfd-wp uses pte markers to mark wr-protected pages for both shmem > and hugetlb. Shmem has pre-allocation ready for markers, but hugetlb path > was overlooked. > > Doing so by calling huge_pte_alloc() if the initial pgtable walk fails to > find the huge ptep. It's possible that huge_pte_alloc() can fail with high > memory pressure, in that case stop the loop immediately and fail silently. > This is not the most ideal solution but it matches with what we do with > shmem meanwhile it avoids the splat in dmesg. > > Cc: linux-stable # 5.19+ > Fixes: 60dfaad65aa9 ("mm/hugetlb: allow uffd wr-protect none ptes") > Reported-by: James Houghton > Signed-off-by: Peter Xu > --- > mm/hugetlb.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) Acked-by: James Houghton