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[23.128.96.18]) by mx.google.com with ESMTP id ob24si12853542ejb.701.2020.06.24.11.51.03; Wed, 24 Jun 2020 11:51:27 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@ziepe.ca header.s=google header.b=TK3CFbKk; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405996AbgFXSsH (ORCPT + 99 others); Wed, 24 Jun 2020 14:48:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405581AbgFXSsH (ORCPT ); Wed, 24 Jun 2020 14:48:07 -0400 Received: from mail-qk1-x743.google.com (mail-qk1-x743.google.com [IPv6:2607:f8b0:4864:20::743]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 25EF1C061573 for ; Wed, 24 Jun 2020 11:48:07 -0700 (PDT) Received: by mail-qk1-x743.google.com with SMTP id 145so331233qke.9 for ; Wed, 24 Jun 2020 11:48:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=eETegcECrqvywpE3KsL+8WK3hMwkFIOHNGmh0aWGRFA=; b=TK3CFbKkxiJln4JU3katp8P1wCphmM8l24Pu1y7cIzE7uqmb01MGeURvRdKy75rFUq PKojLEKtdIPvfWqaGlgUR1ZXP5NeTA26kTDgafmMoBNa8R3UoHWyIIlrUJvwmhvuTRE8 wLTSkPsFDQt5TD6zsiTgmRPBuIZbVZKyheVW48Bfqb/4qPi6U271rlHt+Kap8WhSYOaG gwIqbMm7+jrtyFheUdJuP/0bIQDCTC1e8auU1g2KXVoEB6L7Ty/1mg+E0mmfYrY1VugH 8i/FD9MJFVLBnUSbSe6jsl+QhevOv0D9zbbnoUqw3H5nSLKfybbs+dlsgvEMSEV8l+j3 qICQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=eETegcECrqvywpE3KsL+8WK3hMwkFIOHNGmh0aWGRFA=; b=S+Ogk/S0LOelbYZcIsTHhnJD09vxhQCJC/RYQUIZwMJJresG78SyMdGM/sTXdpYD5N hXVimOyoSb/C7giLI5XKZQuns8YP0oqJ1xdUdripoCXYPkByWV9IJCT3xf6DVFC8Xpj1 pJzczJmQ79D2BWF9c6LH4s+d3xkZg//GFLGUY0laQjXxZnEcM0zEVhOYhMesj5LAEujG 5hdeVLF0JnSrIbq5NoOCwGD8fdjMUbRc1kpl4siDNFJfEVrts1cW4Ji60tBI0NVbLUOr zRYAJqehVT9XOlBSHqMlpBMFPluYczMzWQ55KDfJ8HCbPmAQqVB/N1fpLdXDFissRM7/ JxxQ== X-Gm-Message-State: AOAM5313nOgCNLq3Kkfjb3rDQM6BESBEJ+RpAUGymyvNg1YHmUl7WbkG a2FPyglY/UbD44rqM0CVwhGUJESz5NhBWg== X-Received: by 2002:a37:9a01:: with SMTP id c1mr4508370qke.111.1593024486213; Wed, 24 Jun 2020 11:48:06 -0700 (PDT) Received: from ziepe.ca ([206.223.160.26]) by smtp.gmail.com with ESMTPSA id j7sm2913342qtd.53.2020.06.24.11.48.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Jun 2020 11:48:05 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.93) (envelope-from ) id 1joARI-00DgLI-MZ; Wed, 24 Jun 2020 15:48:04 -0300 Date: Wed, 24 Jun 2020 15:48:04 -0300 From: Jason Gunthorpe To: Chris Wilson Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, Andrew Morton Subject: Re: [PATCH 1/2] mm/mmu_notifier: Mark up direct reclaim paths with MAYFAIL Message-ID: <20200624184804.GL6578@ziepe.ca> References: <20200624121053.GD6578@ziepe.ca> <159300126338.4527.3968787379471939056@build.alporthouse.com> <20200624123910.GA3178169@ziepe.ca> <159300796224.4527.2014771396582759689@build.alporthouse.com> <20200624141604.GH6578@ziepe.ca> <159300850942.4527.8335506003268197914@build.alporthouse.com> <20200624142544.GI6578@ziepe.ca> <159300945202.4527.4366416413140642633@build.alporthouse.com> <20200624165057.GJ6578@ziepe.ca> <159302152915.4527.9099070806700792078@build.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <159302152915.4527.9099070806700792078@build.alporthouse.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 24, 2020 at 06:58:49PM +0100, Chris Wilson wrote: > > I'm still a little unclear on what you are trying to fix - pinned > > pages are definitely not freed, do you have some case where pages > > which are pinned are being cleaned out from the MM despite being > > pinned? Sounds a bit strange, maybe that is worth adressing directly? > > It suffices to say that pin_user_pages does not prevent try_to_unmap_one > from trying to revoke the page. This doesn't sound right.. Maybe there are some odd ball cases, but in common things like page out we absolutely cannot page out or discard pages under DMA. This would be a significant bug. What is the actual problem here? Jason