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 D277FCA0EE4 for ; Sat, 16 Aug 2025 07:34:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6E6848E023C; Sat, 16 Aug 2025 03:34:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 697648E000B; Sat, 16 Aug 2025 03:34:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5C6628E023C; Sat, 16 Aug 2025 03:34:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 46D638E000B for ; Sat, 16 Aug 2025 03:34:22 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 0899358A26 for ; Sat, 16 Aug 2025 07:34:22 +0000 (UTC) X-FDA: 83781807564.25.A60C082 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf21.hostedemail.com (Postfix) with ESMTP id 5B79A1C0003 for ; Sat, 16 Aug 2025 07:34:20 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=nycIx506; spf=pass (imf21.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1755329660; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=uDw0oBL3Va0OnluBaQtZqi3/A0ErKLAzhvTzXPaxkTY=; b=HIIWtm1xwUVuBPefyt8kQxW0b9ad5Q1Ey1HIeJFCSlT5e0rUH6Za60J4a1qajKdcXkHjka IMhBLzc29ukkQNTGl6NogxBeOWC/nErIbpLI6lXzCAjHO4pdBgALFXw+wtNCFqVmf+/cse mdDAuywcnDDQidfUy7ktq+2EkZemb2w= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=nycIx506; spf=pass (imf21.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1755329660; a=rsa-sha256; cv=none; b=luzW84qinMc/w2gw9/j3m+C4cJ9x5LhceFPaQdT7mPFjJLny/LjM5taugYJJ5nvkzUZKG1 5eeXWnCJ9Kui+aB4mKbOIymkE7Rz/3neGHu7Z/0fPzOIZRCxiWLi9ou0UMLE7vTVoCWysM bbvMXRRBTV/0ePSU57N/Nk/CD2ywIiY= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 64BB25C49B4; Sat, 16 Aug 2025 07:34:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B273EC4CEEF; Sat, 16 Aug 2025 07:34:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1755329659; bh=RBllP1HyuurzngS1PYFclVqgZxQMsi/60lRopv0XgZs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=nycIx506DjjSuPyBwZha4dR4dyULJn+oZM7AxMBlxDvtnotMOCCCtdejoR/8MEOND +iwwu3/QA833OQNZvhpg01GPq5VHljkRvw8UeRkJA0hpM3D6wGzqGGMo4oe1WC6HfL Cc82ObFNcUhvbo9BctYnSIjtatfuWm8qXsnYVHbQ= Date: Sat, 16 Aug 2025 00:34:18 -0700 From: Andrew Morton To: David Hildenbrand Cc: Xiang Gao , lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, gaoxiang17 Subject: Re: [PATCH] mm/cma: print total and used pages in cma_alloc() Message-Id: <20250816003418.b2a62f6ddbcf9468fde87a18@linux-foundation.org> In-Reply-To: <701bfbb4-6c12-4614-a322-def3ca923c78@redhat.com> References: <20250816042842.3959315-1-gxxa03070307@gmail.com> <20250815234528.882ab58247cefc96e4137811@linux-foundation.org> <701bfbb4-6c12-4614-a322-def3ca923c78@redhat.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: jfobsm5b18hfto71pci73orq5grtszpu X-Rspam-User: X-Rspamd-Queue-Id: 5B79A1C0003 X-Rspamd-Server: rspam01 X-HE-Tag: 1755329660-466928 X-HE-Meta: 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 feDTFOgr 4LE8Gd3+xVgyN3nTeljLsxHreWkLOBc/0Qnwu7rUX81/Bt7hfxEZ8LTqMdfvoOex/w8zpMzNXOJFpBpi1dWMgytuhiTFhFU9aVZdCCjmLl5ACilQ9gu3YpOls//4tSgzMnR17oYviunq2FsosLGPlrssuWRtgCEy9GLxDf8ZlKuhNV+fsouTRew1lzNV8WSvLrI0pmI/xEPZQAtUvCoeOQksAUReplDDVx+VFLnGU+3sG6GgEA2Y1fQsEFOAzdypWv71De05vAdLD6UPDuMFkgLwyFYiy9nmbNpw6s3PFKJfQS3Qh/XvXrYofbXC/C2luNTYC 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: List-Subscribe: List-Unsubscribe: On Sat, 16 Aug 2025 08:56:47 +0200 David Hildenbrand wrote: > On 16.08.25 08:45, Andrew Morton wrote: > > On Sat, 16 Aug 2025 08:27:39 +0200 David Hildenbrand wrote: > > > >>> @@ -858,8 +869,8 @@ static struct page *__cma_alloc(struct cma *cma, unsigned long count, > >>> if (!cma || !cma->count) > >>> return page; > >>> > >>> - pr_debug("%s(cma %p, name: %s, count %lu, align %d)\n", __func__, > >>> - (void *)cma, cma->name, count, align); > >>> + pr_debug("%s(cma %p, name: %s, total pages: %lu, used pages: %lu, request pages: %lu, align %d)\n", > >>> + __func__, (void *)cma, cma->name, cma->count, cma_get_used_pages(cma), count, align); > >> > >> ^ one space missing for proper indentation. > >> > >> But doing another spinlock cycle just for debugging purposes? That does > >> not feel right, sorry. > > > > If we're calling pr_debug() frequently enough for this to matter, we > > have other problems! > > We call it for each and every actual CMA allocation? I really don't see > why we want to just randomly make CMA allocation latency worse. pr_debug() is 12 million times more expensive than a spin_lock()! > Is the existing pr_debug() a problem? Maybe. But who actually has debug > messages enabled in any sane setup? Nobody, clearly. If anyone enabled pr_debug() in here, they'd immediately have to remove those statements to get any work done. Kill it.