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Tue, 09 Feb 2021 08:51:37 -0500 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-350-nALoMyweNGqXvByXS8dBFg-1; Tue, 09 Feb 2021 08:51:33 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 84E01835E23; Tue, 9 Feb 2021 13:51:31 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-141.ams2.redhat.com [10.36.113.141]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3869060CCF; Tue, 9 Feb 2021 13:51:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612878695; 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=mqHiffMuAITQ06yIJJty7geoczhxpGQAvMCloV6lq9M=; b=BRcgk0CqnsndyqjmyVwkqbAhKnC1Np8rcuEC9qttfsSeLFWB67amMVWW1pqqzqRvjqVh1z vT7fiSEmKMk+OHzWKEjfr4K5b6wbFSBholcsMdLFdrtuCoZgUp00CpX4bc987qFiR64Mwc /tDvjIlFVt7OC043qpFGnVciCCSpsa8= X-MC-Unique: nALoMyweNGqXvByXS8dBFg-1 From: David Hildenbrand To: qemu-devel@nongnu.org Subject: [PATCH v1 9/9] hostmem: wire up RAM_NORESERVE via "reserve" property Date: Tue, 9 Feb 2021 14:49:39 +0100 Message-Id: <20210209134939.13083-10-david@redhat.com> In-Reply-To: <20210209134939.13083-1-david@redhat.com> References: <20210209134939.13083-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=63.128.21.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.57, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_FILL_THIS_FORM_SHORT=0.01 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Let's provide a way to control the use of RAM_NORESERVE via memory backends using the "reserve" property which defaults to true (old behavior). Only POSIX supports setting the flag (and Linux support is checked at runtime, depending on the setting of "/proc/sys/vm/overcommit_memory"). Windows will bail out. The target use case is virtio-mem, which dynamically exposes memory inside a large, sparse memory area to the VM. This essentially allows avoiding to set "/proc/sys/vm/overcommit_memory =3D=3D 0") when using virtio-mem and also supporting hugetlbfs in the future. Signed-off-by: David Hildenbrand Reviewed-by: Peter Xu --- backends/hostmem-file.c | 11 ++++++----- backends/hostmem-memfd.c | 1 + backends/hostmem-ram.c | 1 + backends/hostmem.c | 33 +++++++++++++++++++++++++++++++++ include/sysemu/hostmem.h | 2 +- 5 files changed, 42 insertions(+), 6 deletions(-) diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c index 733408e076..a2d7e83f9c 100644 --- a/backends/hostmem-file.c +++ b/backends/hostmem-file.c @@ -40,6 +40,7 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Err= or **errp) object_get_typename(OBJECT(backend))); #else HostMemoryBackendFile *fb =3D MEMORY_BACKEND_FILE(backend); + uint32_t ram_flags; gchar *name; =20 if (!backend->size) { @@ -52,11 +53,11 @@ file_backend_memory_alloc(HostMemoryBackend *backend, E= rror **errp) } =20 name =3D host_memory_backend_get_name(backend); - memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), - name, - backend->size, fb->align, - (backend->share ? RAM_SHARED : 0) | - (fb->is_pmem ? RAM_PMEM : 0), + ram_flags =3D backend->share ? RAM_SHARED : 0; + ram_flags |=3D backend->reserve ? 0 : RAM_NORESERVE; + ram_flags |=3D fb->is_pmem ? RAM_PMEM : 0; + memory_region_init_ram_from_file(&backend->mr, OBJECT(backend), name, + backend->size, fb->align, ram_flags, fb->mem_path, fb->readonly, errp); g_free(name); #endif diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c index 54db08de0d..5412e67bad 100644 --- a/backends/hostmem-memfd.c +++ b/backends/hostmem-memfd.c @@ -55,6 +55,7 @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Er= ror **errp) =20 name =3D host_memory_backend_get_name(backend); ram_flags =3D backend->share ? RAM_SHARED : 0; + ram_flags |=3D backend->reserve ? 0 : RAM_NORESERVE; memory_region_init_ram_from_fd(&backend->mr, OBJECT(backend), name, backend->size, ram_flags, fd, errp); g_free(name); diff --git a/backends/hostmem-ram.c b/backends/hostmem-ram.c index 741e701062..b8e55cdbd0 100644 --- a/backends/hostmem-ram.c +++ b/backends/hostmem-ram.c @@ -29,6 +29,7 @@ ram_backend_memory_alloc(HostMemoryBackend *backend, Erro= r **errp) =20 name =3D host_memory_backend_get_name(backend); ram_flags =3D backend->share ? RAM_SHARED : 0; + ram_flags |=3D backend->reserve ? 0 : RAM_NORESERVE; memory_region_init_ram_flags_nomigrate(&backend->mr, OBJECT(backend), = name, backend->size, ram_flags, errp); g_free(name); diff --git a/backends/hostmem.c b/backends/hostmem.c index be0c3b079f..c979595115 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -217,6 +217,11 @@ static void host_memory_backend_set_prealloc(Object *o= bj, bool value, Error *local_err =3D NULL; HostMemoryBackend *backend =3D MEMORY_BACKEND(obj); =20 + if (!backend->reserve && value) { + error_setg(errp, "'prealloc=3Don' and 'reserve=3Doff' are incompat= ible"); + return; + } + if (!host_memory_backend_mr_inited(backend)) { backend->prealloc =3D value; return; @@ -268,6 +273,7 @@ static void host_memory_backend_init(Object *obj) /* TODO: convert access to globals to compat properties */ backend->merge =3D machine_mem_merge(machine); backend->dump =3D machine_dump_guest_core(machine); + backend->reserve =3D true; backend->prealloc_threads =3D 1; } =20 @@ -426,6 +432,28 @@ static void host_memory_backend_set_share(Object *o, b= ool value, Error **errp) backend->share =3D value; } =20 +static bool host_memory_backend_get_reserve(Object *o, Error **errp) +{ + HostMemoryBackend *backend =3D MEMORY_BACKEND(o); + + return backend->reserve; +} + +static void host_memory_backend_set_reserve(Object *o, bool value, Error *= *errp) +{ + HostMemoryBackend *backend =3D MEMORY_BACKEND(o); + + if (host_memory_backend_mr_inited(backend)) { + error_setg(errp, "cannot change property value"); + return; + } + if (backend->prealloc && !value) { + error_setg(errp, "'prealloc=3Don' and 'reserve=3Doff' are incompat= ible"); + return; + } + backend->reserve =3D value; +} + static bool host_memory_backend_get_use_canonical_path(Object *obj, Error **errp) { @@ -494,6 +522,11 @@ host_memory_backend_class_init(ObjectClass *oc, void *= data) host_memory_backend_get_share, host_memory_backend_set_share); object_class_property_set_description(oc, "share", "Mark the memory as private to QEMU or shared"); + object_class_property_add_bool(oc, "reserve", + host_memory_backend_get_reserve, host_memory_backend_set_reserve); + object_class_property_set_description(oc, "reserve", + "Reserve swap space (or huge pages under Linux) for the whole memo= ry" + " backend, if supported by the OS."); object_class_property_add_bool(oc, "x-use-canonical-path-for-ramblock-= id", host_memory_backend_get_use_canonical_path, host_memory_backend_set_use_canonical_path); diff --git a/include/sysemu/hostmem.h b/include/sysemu/hostmem.h index df5644723a..9ff5c16963 100644 --- a/include/sysemu/hostmem.h +++ b/include/sysemu/hostmem.h @@ -64,7 +64,7 @@ struct HostMemoryBackend { /* protected */ uint64_t size; bool merge, dump, use_canonical_path; - bool prealloc, is_mapped, share; + bool prealloc, is_mapped, share, reserve; uint32_t prealloc_threads; DECLARE_BITMAP(host_nodes, MAX_NODES + 1); HostMemPolicy policy; --=20 2.29.2