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[74.12.30.48]) by smtp.gmail.com with ESMTPSA id j15-20020a05620a288f00b006a5d2eb58b2sm15868309qkp.33.2022.07.19.13.49.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Jul 2022 13:49:09 -0700 (PDT) Date: Tue, 19 Jul 2022 16:49:08 -0400 From: Peter Xu To: Nadav Amit Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Mike Rapoport , Axel Rasmussen , Nadav Amit , Andrea Arcangeli , Andrew Cooper , Andy Lutomirski , Dave Hansen , David Hildenbrand , Peter Zijlstra , Thomas Gleixner , Will Deacon , Yu Zhao , Nick Piggin Subject: Re: [RFC PATCH 02/14] userfaultfd: try to map write-unprotected pages Message-ID: References: <20220718120212.3180-1-namit@vmware.com> <20220718120212.3180-3-namit@vmware.com> MIME-Version: 1.0 In-Reply-To: <20220718120212.3180-3-namit@vmware.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=f4tXHIxx; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf25.hostedemail.com: domain of peterx@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=peterx@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658263757; 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=0dY9FUBIg9nO3hNynwxm9uMsgMR67CPlIx/HDrEEy+A=; b=0JxOZ/aAMkhw7a5a+diZ8WT2NLGy/bKntaVcAObgnKpk9L3mUo3dFYKk0x/92zbcJfSZ0D Q4jlgDoDkQY/nppmPTL/5tCJWWiS04R7lW1dD9pxHggulAN90BKRTO+gfZex1a2Ro4OA/X 1U50ljEiSz4xxPW4mno4QsilXL50FIo= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658263757; a=rsa-sha256; cv=none; b=gjfJm9GzVq2IE9uZcICHCOzCJ7RIZEmBqR5484u/3Fi74sSVJgKx5eZnOxe2QZz7Mb/gFl arrwKe6EtJHNPHE5Su125uAsCKM37Vj6+WrwtEoTXQzABVrkpqzGMYWu48MVS2PND+okRF iU8PCAm0j3BxnYc9tP/071SmK+/7+as= X-Rspamd-Queue-Id: 1BA0DA009E Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=f4tXHIxx; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf25.hostedemail.com: domain of peterx@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=peterx@redhat.com X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: fattjb6en7rcwacfmqx8mtbt91q5h6x7 X-HE-Tag: 1658263756-826754 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 Mon, Jul 18, 2022 at 05:02:00AM -0700, Nadav Amit wrote: > From: Nadav Amit > > When using userfaultfd write-(un)protect ioctl, try to change the PTE to > be writable. This would save a page-fault afterwards. > > Cc: Andrea Arcangeli > Cc: Andrew Cooper > Cc: Andrew Morton > Cc: Andy Lutomirski > Cc: Dave Hansen > Cc: David Hildenbrand > Cc: Peter Xu > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: Will Deacon > Cc: Yu Zhao > Cc: Nick Piggin > Signed-off-by: Nadav Amit Acked-by: Peter Xu -- Peter Xu