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 X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0194C2D0E5 for ; Wed, 25 Mar 2020 17:49:30 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 83C47206F6 for ; Wed, 25 Mar 2020 17:49:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="duXd4P+w" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 83C47206F6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1B6426B00C1; Wed, 25 Mar 2020 13:49:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 18DCF6B00C2; Wed, 25 Mar 2020 13:49:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0CB5D6B00C3; Wed, 25 Mar 2020 13:49:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0052.hostedemail.com [216.40.44.52]) by kanga.kvack.org (Postfix) with ESMTP id EB6206B00C1 for ; Wed, 25 Mar 2020 13:49:29 -0400 (EDT) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B40181828088A for ; Wed, 25 Mar 2020 17:49:29 +0000 (UTC) X-FDA: 76634621658.26.light35_52cfd9af21d51 X-HE-Tag: light35_52cfd9af21d51 X-Filterd-Recvd-Size: 4818 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Wed, 25 Mar 2020 17:49:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=T9S9C6VxKTUm6W+o+fgxsWYwySKC7SBn9F72vKW6w/s=; b=duXd4P+w1UWs8oiwjatjs4S6Ap LpHXfdkrEuF9yW0Mp9BN8tphvYLDKGkQ+A1OjDrmTEammyJs0oXzDnCH9NtOX7y5gH0pNOHj9zdTy lTINqWE3x2/kte5iCryp+WUTA9BUJRYNQQ6hKa4gO7JBwUtROAO2ljdjrHT8Mw0TZofoZPq+tHCut L6d7WNqVpNmTuuEep1eRXlqr0rmpZ33P5mjB13McWeGjQOWbn3Nyo4g4yKv3VHOpNSrIkrBK8VNGr ZIdn4J4nmqpOpuG0FqUAvrvwFtoBdJcCQsMoiD+DFWqIPM1RvqEHe/2K3JEQ2girn5/2M/1a7kt95 7c0Fylhw==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHA9U-0000A8-Ie; Wed, 25 Mar 2020 17:49:16 +0000 Date: Wed, 25 Mar 2020 10:49:16 -0700 From: Matthew Wilcox To: Alexander Potapenko Cc: Michal Hocko , Vegard Nossum , Andrew Morton , Dmitry Vyukov , Marco Elver , Andrey Konovalov , Linux Memory Management List , Al Viro , Andreas Dilger , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , "Darrick J. Wong" , David Miller , Dmitry Torokhov , Eric Biggers , Eric Dumazet , Eric Van Hensbergen , Greg Kroah-Hartman , Harry Wentland , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Mark Rutland , "Martin K . Petersen" , Martin Schwidefsky , "Michael S. Tsirkin" , Michal Simek , Petr Mladek , Qian Cai , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , Theodore Ts'o , Thomas Gleixner , Vasily Gorbik , Wolfram Sang Subject: Re: [PATCH v5 03/38] kmsan: gfp: introduce __GFP_NO_KMSAN_SHADOW Message-ID: <20200325174916.GC22483@bombadil.infradead.org> References: <20200325161249.55095-1-glider@google.com> <20200325161249.55095-4-glider@google.com> <20200325161952.GF19542@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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, Mar 25, 2020 at 06:40:29PM +0100, Alexander Potapenko wrote: > On Wed, Mar 25, 2020 at 6:26 PM Alexander Potapenko wrote: > > > > On Wed, Mar 25, 2020 at 5:19 PM Michal Hocko wrote: > > > > > > On Wed 25-03-20 17:12:14, glider@google.com wrote: > > > > This flag is to be used by KMSAN runtime to mark that newly created > > > > memory pages don't need KMSAN metadata backing them. > > > > > > I really dislike an idea of the gfp flag. If you need some form of > > > exclusion for kmsan allocations then follow the pattern of memalloc_no{fs,io}_{save,restore} > > > History tells us that single usecase gfp flags are too tempting to abuse > > > and using incorrectly. > > > > Great idea, will do! > > Guess PF_ flags isn't a scarce resource? > > Actually, no, we are out of bits in current->flags already. > I could introduce a separate flag into struct task, but that won't > work in interrupt contexts - how do you solve that problem for FS/IO > allocations? I would suggest using bits in the section labelled: /* Unserialized, strictly 'current' */ since this doesn't need to be accessed from any other task. Michal, can we move PF_MEMALLOC_NOIO and NOFS to that area too?