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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C2F5C46467 for ; Mon, 16 Jan 2023 11:45:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230085AbjAPLpM (ORCPT ); Mon, 16 Jan 2023 06:45:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33280 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230134AbjAPLox (ORCPT ); Mon, 16 Jan 2023 06:44:53 -0500 Received: from mail-lj1-x235.google.com (mail-lj1-x235.google.com [IPv6:2a00:1450:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 973611F4B7 for ; Mon, 16 Jan 2023 03:44:46 -0800 (PST) Received: by mail-lj1-x235.google.com with SMTP id y18so26148099ljk.11 for ; Mon, 16 Jan 2023 03:44:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=1Sj8t7w90/b4YfbubGLhW8jse4BDSgEBS6GznI1fgYs=; b=n6YvyCy3rYblvixVSzS5lObopYA/91DnkkB77eze+zE1jeTE1e3i75EUhbc0biSVZP HZHd7fHPuMMnBoGSSK0O8ln+QpdS8vmpGUl6KDpfPh3J14uYrvbmVqyGVFs6M4w1Gijw 78UVPWkVeg8Do6ghRmiEJL+pXCGqCOXSpI8uFUEIPrybLJ+uZmTDSmSSdbLuJ8mepKJZ chPE/FhJCju3yBor4q8E0BgnEmk7ok8G9nR90gvl9uoD8cx2brcoXIWSloEGPHioUsFS yI9fwV1oAflY+FDOgg4X12gIuJk0l38dUsd28O+5i4kwDD1EOe8h5mIGvNDUpWQcU0ei Wtag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=1Sj8t7w90/b4YfbubGLhW8jse4BDSgEBS6GznI1fgYs=; b=SGkAnfgZFn8oLm6cUWY6GHxdy6L/xY9bXZGU6fqSahG7oAHvKvJIXIO0HFb1DLPpyY t0T5oYs/msez9NDlNgDVa0y5Q+FQ5/8M29I5Yvjme0tGJSNLEH2f8BMYh1Szb+vY5f18 qnHC8x7o/3p+ogaVlQXTLfYqExPqQ3OuNqiYQFfd57/5z/dtqk/U1Ein+WG7JSUQ914t 64MPCVGdvIy2/GGEEzp7nIGGXnbTyT/EoHz2AeIxFb2wI/FRqWWwF22ftMJlAQdct9Bh ENhOITDIv+g75nRfsqGfpPfKd85JxJaD3uBnx+24fwXpTKhX6EfNl+94h0a+iLNJk8bl OrkA== X-Gm-Message-State: AFqh2koTqntsQZSSesGJ4kmpjYwfUBFqyjveeQnaMSOhqHXKwIP0bIIh HQ7fV9OOvU74TMkb6x2dUY4= X-Google-Smtp-Source: AMrXdXugYckFR5zuwXZ4nj4hn5Lzy79WsRw0BBu8l4Tp8lQpK6eAufF1o1yGqjaZnfsI+IvzkU6c7Q== X-Received: by 2002:a2e:9c85:0:b0:284:819:1f85 with SMTP id x5-20020a2e9c85000000b0028408191f85mr10871890lji.40.1673869484830; Mon, 16 Jan 2023 03:44:44 -0800 (PST) Received: from pc636 (host-90-235-24-7.mobileonline.telia.com. [90.235.24.7]) by smtp.gmail.com with ESMTPSA id f17-20020a2e6a11000000b00282cffdfe6asm3326139ljc.61.2023.01.16.03.44.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Jan 2023 03:44:44 -0800 (PST) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Mon, 16 Jan 2023 12:44:42 +0100 To: Baoquan He Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, urezki@gmail.com, lstoakes@gmail.com, stephen.s.brennan@oracle.com, willy@infradead.org, akpm@linux-foundation.org, hch@infradead.org Subject: Re: [PATCH v3 5/7] mm/vmalloc: skip the uninitilized vmalloc areas Message-ID: References: <20230113031921.64716-1-bhe@redhat.com> <20230113031921.64716-6-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230113031921.64716-6-bhe@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 13, 2023 at 11:19:19AM +0800, Baoquan He wrote: > For areas allocated via vmalloc_xxx() APIs, it searches for unmapped area > to reserve and allocates new pages to map into, please see function > __vmalloc_node_range(). During the process, flag VM_UNINITIALIZED is set > in vm->flags to indicate that the pages allocation and mapping haven't > been done, until clear_vm_uninitialized_flag() is called to clear it. > > For this kind of area, if VM_UNINITIALIZED is still set, let's ignore > it in vread() because pages newly allocated and being mapped in that > area only contains zero data. reading them out by aligned_vread() is > wasting time. > > Signed-off-by: Baoquan He > --- > mm/vmalloc.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 4a10b3b692fa..dbcdcad2276b 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3660,6 +3660,11 @@ long vread(char *buf, char *addr, unsigned long count) > if (!vm && !flags) > continue; > > + if (vm && (vm->flags & VM_UNINITIALIZED)) > + continue; > + /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ > + smp_rmb(); > + > vaddr = (char *) va->va_start; > size = vm ? get_vm_area_size(vm) : va_size(va); > > -- > 2.34.1 > Reviewed-by: Uladzislau Rezki (Sony) -- Uladzislau Rezki