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=-6.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 21254C3524D for ; Mon, 3 Feb 2020 18:35:56 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E0C4A2086A for ; Mon, 3 Feb 2020 18:35:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QHxVOwAe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E0C4A2086A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45828 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iygZf-00047M-3t for qemu-devel@archiver.kernel.org; Mon, 03 Feb 2020 13:35:55 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59741) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iygWI-00085b-LY for qemu-devel@nongnu.org; Mon, 03 Feb 2020 13:32:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iygWG-0001q4-4Z for qemu-devel@nongnu.org; Mon, 03 Feb 2020 13:32:25 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:29400 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iygWF-0001nU-Vg for qemu-devel@nongnu.org; Mon, 03 Feb 2020 13:32:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580754742; 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=yiFlwfNNxg1lbxKs5NIEPv1MehTMQy7VN8Wu+aD6HJk=; b=QHxVOwAekrzW1dcSQyp+x+X+fF1HN9CIeJqmOXYWAqh62XOqkIO/rrjf5AI4UiKtvFNyjl tdTOQH4ijt6QrveZw8S8b7w6HkNhaux8seb4va4zADHJIZ6YBX7t8BzwfKIaq3ZydkxeGQ 1l8AL3cwR7toNwX2/+yik7NIN3v1dok= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-289-asMZ0xMGPcqcRBB7iWYjgw-1; Mon, 03 Feb 2020 13:32:19 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C49041084433; Mon, 3 Feb 2020 18:32:17 +0000 (UTC) Received: from t480s.redhat.com (ovpn-117-77.ams2.redhat.com [10.36.117.77]) by smtp.corp.redhat.com (Postfix) with ESMTP id E02C85DAB0; Mon, 3 Feb 2020 18:32:15 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v1 09/13] util/mmap-alloc: Implement resizable mmaps Date: Mon, 3 Feb 2020 19:31:21 +0100 Message-Id: <20200203183125.164879-10-david@redhat.com> In-Reply-To: <20200203183125.164879-1-david@redhat.com> References: <20200203183125.164879-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: asMZ0xMGPcqcRBB7iWYjgw-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eduardo Habkost , "Michael S . Tsirkin" , David Hildenbrand , "Dr . David Alan Gilbert" , Greg Kurz , Murilo Opsfelder Araujo , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Implement resizable mmaps. For now, the actual resizing is not wired up. Introduce qemu_ram_mmap_resizable() and qemu_ram_mmap_resize(). Make qemu_ram_mmap() a wrapper of qemu_ram_mmap_resizable(). Cc: "Michael S. Tsirkin" Cc: Greg Kurz Cc: Murilo Opsfelder Araujo Cc: Eduardo Habkost Cc: "Dr. David Alan Gilbert" Signed-off-by: David Hildenbrand --- include/qemu/mmap-alloc.h | 21 ++++++++++++------- util/mmap-alloc.c | 44 ++++++++++++++++++++++++++++----------- 2 files changed, 45 insertions(+), 20 deletions(-) diff --git a/include/qemu/mmap-alloc.h b/include/qemu/mmap-alloc.h index e786266b92..70bc8e9637 100644 --- a/include/qemu/mmap-alloc.h +++ b/include/qemu/mmap-alloc.h @@ -7,11 +7,13 @@ size_t qemu_fd_getpagesize(int fd); size_t qemu_mempath_getpagesize(const char *mem_path); =20 /** - * qemu_ram_mmap: mmap the specified file or device. + * qemu_ram_mmap_resizable: reserve a memory region of @max_size to mmap t= he + * specified file or device and mmap @size of it. * * Parameters: * @fd: the file or the device to mmap * @size: the number of bytes to be mmaped + * @max_size: the number of bytes to be reserved * @align: if not zero, specify the alignment of the starting mapping add= ress; * otherwise, the alignment in use will be determined by QEMU. * @shared: map has RAM_SHARED flag. @@ -21,12 +23,15 @@ size_t qemu_mempath_getpagesize(const char *mem_path); * On success, return a pointer to the mapped area. * On failure, return MAP_FAILED. */ -void *qemu_ram_mmap(int fd, - size_t size, - size_t align, - bool shared, - bool is_pmem); - -void qemu_ram_munmap(int fd, void *ptr, size_t size); +void *qemu_ram_mmap_resizable(int fd, size_t size, size_t max_size, + size_t align, bool shared, bool is_pmem); +void *qemu_ram_mmap_resize(void *ptr, int fd, size_t old_size, size_t new_= size, + bool shared, bool is_pmem); +static inline void *qemu_ram_mmap(int fd, size_t size, size_t align, + bool shared, bool is_pmem) +{ + return qemu_ram_mmap_resizable(fd, size, size, align, shared, is_pmem)= ; +} +void qemu_ram_munmap(int fd, void *ptr, size_t max_size); =20 #endif diff --git a/util/mmap-alloc.c b/util/mmap-alloc.c index 63ad6893b7..2d562145e9 100644 --- a/util/mmap-alloc.c +++ b/util/mmap-alloc.c @@ -172,11 +172,8 @@ static inline size_t mmap_pagesize(int fd) #endif } =20 -void *qemu_ram_mmap(int fd, - size_t size, - size_t align, - bool shared, - bool is_pmem) +void *qemu_ram_mmap_resizable(int fd, size_t size, size_t max_size, + size_t align, bool shared, bool is_pmem) { const size_t pagesize =3D mmap_pagesize(fd); size_t offset, total; @@ -184,12 +181,14 @@ void *qemu_ram_mmap(int fd, =20 /* we can only map whole pages */ size =3D QEMU_ALIGN_UP(size, pagesize); + max_size =3D QEMU_ALIGN_UP(max_size, pagesize); =20 /* * Note: this always allocates at least one extra page of virtual addr= ess - * space, even if size is already aligned. + * space, even if the size is already aligned. We will reserve an area= of + * at least max_size, but only populate the requested part of it. */ - total =3D size + align; + total =3D max_size + align; =20 guardptr =3D mmap_reserve(0, total, fd); if (guardptr =3D=3D MAP_FAILED) { @@ -217,22 +216,43 @@ void *qemu_ram_mmap(int fd, * a guard page guarding against potential buffer overflows. */ total -=3D offset; - if (total > size + pagesize) { - munmap(ptr + size + pagesize, total - size - pagesize); + if (total > max_size + pagesize) { + munmap(ptr + max_size + pagesize, total - max_size - pagesize); } =20 return ptr; } =20 -void qemu_ram_munmap(int fd, void *ptr, size_t size) +void *qemu_ram_mmap_resize(void *ptr, int fd, size_t old_size, size_t new_= size, + bool shared, bool is_pmem) { const size_t pagesize =3D mmap_pagesize(fd); =20 /* we can only map whole pages */ - size =3D QEMU_ALIGN_UP(size, pagesize); + old_size =3D QEMU_ALIGN_UP(old_size, pagesize); + new_size =3D QEMU_ALIGN_UP(new_size, pagesize); + + /* we support actually resizable memory regions only on Linux */ + if (old_size < new_size) { + /* populate the missing piece into the reserved area */ + ptr =3D mmap_populate(ptr + old_size, new_size - old_size, fd, old= _size, + shared, is_pmem); + } else if (old_size > new_size) { + /* discard this piece, keeping the area reserved (should never fai= l) */ + ptr =3D mmap_reserve(ptr + new_size, old_size - new_size, fd); + } + return ptr; +} + +void qemu_ram_munmap(int fd, void *ptr, size_t max_size) +{ + const size_t pagesize =3D mmap_pagesize(fd); + + /* we can only map whole pages */ + max_size =3D QEMU_ALIGN_UP(max_size, pagesize); =20 if (ptr) { /* Unmap both the RAM block and the guard page */ - munmap(ptr, size + pagesize); + munmap(ptr, max_size + pagesize); } } --=20 2.24.1