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=-8.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, 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 20E2BC433E0 for ; Fri, 5 Mar 2021 10:19:01 +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 A8B3E64EE8 for ; Fri, 5 Mar 2021 10:19:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A8B3E64EE8 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]:41630 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lI7Xv-0006rx-Ko for qemu-devel@archiver.kernel.org; Fri, 05 Mar 2021 05:18:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:46122) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lI7W0-0005QL-Qh for qemu-devel@nongnu.org; Fri, 05 Mar 2021 05:17:00 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:43851) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lI7Vz-0000JX-1e for qemu-devel@nongnu.org; Fri, 05 Mar 2021 05:17:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614939415; 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; bh=5Y1M1d391uOplNVMwxXUq0UfXN29arv2SAlLv+184lA=; b=KOdEu4tJceT5+kOMSRUYzhyzB6g//sAj27Lm33vMRzl4LXgI3KERTMmWyW8dk7ZaUMtf63 Qymm/M1PB6A4DOPQuHUIUngEY6ld3HhqWJN2chzdzlunCyabIDEYm3CIq2RIyaHbKpSfLi hg550mwaNka656QPuXK2GCWF/Oz2vNc= 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-331-Z-3qMECOM0m3T0pEupiJmw-1; Fri, 05 Mar 2021 05:16:53 -0500 X-MC-Unique: Z-3qMECOM0m3T0pEupiJmw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1B492800D53; Fri, 5 Mar 2021 10:16:52 +0000 (UTC) Received: from t480s.redhat.com (ovpn-112-194.ams2.redhat.com [10.36.112.194]) by smtp.corp.redhat.com (Postfix) with ESMTP id C47C61001B2C; Fri, 5 Mar 2021 10:16:35 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v2 0/9] RAM_NORESERVE, MAP_NORESERVE and hostmem "reserve" property Date: Fri, 5 Mar 2021 11:16:25 +0100 Message-Id: <20210305101634.10745-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: Juan Quintela , Murilo Opsfelder Araujo , Cornelia Huck , Eduardo Habkost , "Michael S. Tsirkin" , Stefan Weil , David Hildenbrand , Richard Henderson , "Dr. David Alan Gilbert" , Peter Xu , Greg Kurz , Halil Pasic , Christian Borntraeger , Stefan Hajnoczi , Igor Mammedov , Thomas Huth , Paolo Bonzini , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Igor Kotrasinski Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Some cleanups previously sent in other context (resizeable allocations), followed by RAM_NORESERVE, implementing it under POSIX using MAP_NORESERVE, and letting users configure it for memory backens using the "reserve" property (default: true). MAP_NORESERVE under Linux has in the context of QEMU an effect on 1) Private anonymous memory -> memory-backend-ram,id=mem0,size=10G 2) Private file-based mappings -> memory-backend-file,id=mem0,size=10G,mem-path=/dev/shm/0 3) Private/shared hugetlbfs memory -> memory-backend-memfd,id=mem0,size=10G,hugetlb=on,hugetlbsize=2M With MAP_NORESERVE/"reserve=off", we won't be reserving swap space (1/2) or huge pages (3) for the whole memory region. The target use case is virtio-mem, which dynamically exposes memory inside a large, sparse memory area to the VM. MAP_NORESERVE tells the OS "this mapping might be very sparse". This essentially allows avoiding to set "/proc/sys/vm/overcommit_memory == 1") when using virtio-mem and also supporting hugetlbfs in the future. virtio-mem currently only supports anonymous memory, in the future we want to also support private memfd, shared file-based and shared hugetlbfs mappings. virtio-mem features I am currently working on include: 1. Introducing a prealloc option for virtio-mem (e.g., using fallocate() when plugging blocks) to fail nicely when running out of backing storage like huge pages. 2. Supporting resizable RAM block/memmory regions, such that we won't always expose a large, sparse memory region to the VM. 3. Handling virtio-mem requests via an iothread to not hold the BQL while populating/preallocating memory 4. Protecting unplugged memory e.g., using userfaultfd. 5. (resizeable allocations / optimized mmap handling when resizing RAM blocks) Based-on: 20210303130916.22553-1-david@redhat.com v1 -> v2: - Rebased to upstream and phs_mem_alloc simplifications -- Upsteam added the "map_offset" parameter to many RAM allocation interfaces. - "softmmu/physmem: Drop "shared" parameter from ram_block_add()" -- Use local variable "shared" - "memory: introduce RAM_NORESERVE and wire it up in qemu_ram_mmap()" -- Simplify due to phs_mem_alloc changes - "util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE" -- Add a whole bunch of comments. -- Exclude shared anonymous memory that QEMU doesn't use -- Special-case readonly mappings Cc: Peter Xu Cc: "Michael S. Tsirkin" Cc: Eduardo Habkost Cc: "Dr. David Alan Gilbert" Cc: Richard Henderson Cc: Paolo Bonzini Cc: Igor Mammedov Cc: "Philippe Mathieu-Daudé" Cc: Stefan Hajnoczi Cc: Murilo Opsfelder Araujo Cc: Greg Kurz Cc: Liam Merwick David Hildenbrand (9): softmmu/physmem: Drop "shared" parameter from ram_block_add() util/mmap-alloc: Factor out calculation of the pagesize for the guard page util/mmap-alloc: Factor out reserving of a memory region to mmap_reserve() util/mmap-alloc: Factor out activating of memory to mmap_activate() softmmu/memory: Pass ram_flags into qemu_ram_alloc_from_fd() softmmu/memory: Pass ram_flags into memory_region_init_ram_shared_nomigrate() memory: introduce RAM_NORESERVE and wire it up in qemu_ram_mmap() util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE hostmem: Wire up RAM_NORESERVE via "reserve" property backends/hostmem-file.c | 11 +- backends/hostmem-memfd.c | 8 +- backends/hostmem-ram.c | 7 +- backends/hostmem.c | 33 +++ hw/m68k/next-cube.c | 4 +- hw/misc/ivshmem.c | 5 +- include/exec/cpu-common.h | 1 + include/exec/memory.h | 43 ++-- include/exec/ram_addr.h | 9 +- include/qemu/mmap-alloc.h | 2 + include/qemu/osdep.h | 3 +- include/sysemu/hostmem.h | 2 +- migration/ram.c | 3 +- .../memory-region-housekeeping.cocci | 8 +- softmmu/memory.c | 27 ++- softmmu/physmem.c | 41 ++-- util/mmap-alloc.c | 220 ++++++++++++------ util/oslib-posix.c | 6 +- util/oslib-win32.c | 13 +- 19 files changed, 299 insertions(+), 147 deletions(-) -- 2.29.2