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=-3.5 required=3.0 tests=BAYES_00,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 10129C07E96 for ; Thu, 8 Jul 2021 04:22:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 901AA61417 for ; Thu, 8 Jul 2021 04:22:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 901AA61417 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 565EA6B0011; Thu, 8 Jul 2021 00:22:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 53D896B005D; Thu, 8 Jul 2021 00:22:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3DD666B006C; Thu, 8 Jul 2021 00:22:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0196.hostedemail.com [216.40.44.196]) by kanga.kvack.org (Postfix) with ESMTP id 151336B0011 for ; Thu, 8 Jul 2021 00:22:20 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 69B87183CB1E3 for ; Thu, 8 Jul 2021 04:22:19 +0000 (UTC) X-FDA: 78338123598.15.4CFAFAB Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf19.hostedemail.com (Postfix) with ESMTP id D3E87B0000B6 for ; Thu, 8 Jul 2021 04:22:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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=77m8A8TvwRFVR/JL6IH9OVAJZSv5m+xL9r+uut0gWrE=; b=XPt01X6UkV7rGd6LHEXZR1NKe4 3yW7hiUcn60dUf2JhvwoW4h0q/Wu7LtxE+5EazlbwldAKTxr19PIvq+MCPol0O6DC8NjXFcqJ/WKX TjWv3OT6OB81SAXqjy4FsIVWSmxeCZ8FncVaHc540DT0r0OzOaawhAwnRSR4Ing9OSxJb8O0ke31Q YbpZeSn3Y3HtJdYkyZCRMqg70Qm53VTdYsIY/9aKL21jMOW9AMiOzicFQ3eg5LQGLrwYuPCM0z1pb 5/1FxXV97+cOCmgWBHl2dZhNe9bXkjHSeMTkKYNk8A54+Y2fIJh3LoUeNvNUE8so8qyA82+kJq78O HiV1XAew==; Received: from hch by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1m1LWv-00D4oo-4R; Thu, 08 Jul 2021 04:21:02 +0000 Date: Thu, 8 Jul 2021 05:20:53 +0100 From: Christoph Hellwig To: John Stultz Cc: Christoph Hellwig , lkml , Daniel Vetter , Christian Koenig , Sumit Semwal , Liam Mark , Chris Goldsworthy , Laura Abbott , Brian Starkey , Hridya Valsaraju , Suren Baghdasaryan , Sandeep Patil , Daniel Mentz , ??rjan Eide , Robin Murphy , Ezequiel Garcia , Simon Ser , James Jones , linux-media , dri-devel , Mel Gorman , linux-mm Subject: Re: page pools, was Re: [PATCH v9 1/5] drm: Add a sharable drm page-pool implementation Message-ID: References: <20210630013421.735092-1-john.stultz@linaro.org> <20210630013421.735092-2-john.stultz@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=XPt01X6U; spf=none (imf19.hostedemail.com: domain of BATV@casper.srs.infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=BATV@casper.srs.infradead.org; dmarc=none X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D3E87B0000B6 X-Rspam-User: nil X-Stat-Signature: ocpxj4shr55ebrr5prnbo37gydzap7qf X-HE-Tag: 1625718138-871754 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, Jul 07, 2021 at 12:35:23PM -0700, John Stultz wrote: > So, as Christian mentioned, on the TTM side it's useful, as they are > trying to avoid TLB flushes when changing caching attributes. > > For the dmabuf system heap purposes, the main benefit is moving the > page zeroing to the free path, rather than the allocation path. This > on its own doesn't save much, but allows us to defer frees (and thus > the zeroing) to the background, which can get that work out of the hot > path. I really do no think that is worth it to fragment the free pages.