From nobody Mon Sep 15 11:10:07 2025 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 7DA4EC54EBE for ; Fri, 13 Jan 2023 03:21:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231153AbjAMDVC (ORCPT ); Thu, 12 Jan 2023 22:21:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231349AbjAMDUs (ORCPT ); Thu, 12 Jan 2023 22:20:48 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 954FB559F9 for ; Thu, 12 Jan 2023 19:20:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673580006; h=from:from: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; bh=VSIbSzL2bxKjEoqavrvpRp0pIuSz+KbDY87ApaDwMng=; b=FoTF2/86i83RCxZg1XY9j+RN4ilevmExl3cITgEusJSQQxS/mZVBst6Jz9tbjf0Irqs8+T Lba2kDgSk4OS6rbcCd/F4BaMDEOIFMVJf35a906ka4lV0qzSkG+oV90r8cfA3tj530iKyp PrJB0U1AlTOYkBEBbm36eOcSb9y2pSo= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-610-QVWkk8okPcyjXl0ZR1WrbQ-1; Thu, 12 Jan 2023 22:20:03 -0500 X-MC-Unique: QVWkk8okPcyjXl0ZR1WrbQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8544E85C069; Fri, 13 Jan 2023 03:20:02 +0000 (UTC) Received: from fedora.redhat.com (ovpn-12-229.pek2.redhat.com [10.72.12.229]) by smtp.corp.redhat.com (Postfix) with ESMTP id 31AFB4078903; Fri, 13 Jan 2023 03:19:56 +0000 (UTC) From: Baoquan He To: linux-mm@kvack.org Cc: 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, Baoquan He Subject: [PATCH v3 5/7] mm/vmalloc: skip the uninitilized vmalloc areas Date: Fri, 13 Jan 2023 11:19:19 +0800 Message-Id: <20230113031921.64716-6-bhe@redhat.com> In-Reply-To: <20230113031921.64716-1-bhe@redhat.com> References: <20230113031921.64716-1-bhe@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Lorenzo Stoakes Reviewed-by: Uladzislau Rezki (Sony) --- 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 coun= t) if (!vm && !flags) continue; =20 + if (vm && (vm->flags & VM_UNINITIALIZED)) + continue; + /* Pair with smp_wmb() in clear_vm_uninitialized_flag() */ + smp_rmb(); + vaddr =3D (char *) va->va_start; size =3D vm ? get_vm_area_size(vm) : va_size(va); =20 --=20 2.34.1