From: Peter Xu <peterx@redhat.com>
To: David Hildenbrand <david@redhat.com>
Cc: "Marcel Apfelbaum" <mapfelba@redhat.com>,
"Igor Kotrasinski" <i.kotrasinsk@partner.samsung.com>,
"Eduardo Habkost" <ehabkost@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Murilo Opsfelder Araujo" <muriloo@linux.ibm.com>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
qemu-devel@nongnu.org, "Greg Kurz" <groug@kaod.org>,
"Stefan Hajnoczi" <stefanha@redhat.com>,
"Igor Mammedov" <imammedo@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>
Subject: Re: [PATCH v4 10/14] memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap()
Date: Tue, 23 Mar 2021 16:51:56 -0400 [thread overview]
Message-ID: <20210323205156.GM6486@xz-x1> (raw)
In-Reply-To: <20210319101230.21531-11-david@redhat.com>
On Fri, Mar 19, 2021 at 11:12:26AM +0100, David Hildenbrand wrote:
> Let's introduce RAM_NORESERVE, allowing mmap'ing with MAP_NORESERVE. The
> new flag has the following semantics:
>
> "
> RAM is mmap-ed with MAP_NORESERVE. When set, reserving swap space (or huge
> pages if applicable) is skipped: will bail out if not supported. When not
> set, the OS might do the reservation, depending on OS support.
> "
>
> Allow passing it into:
> - memory_region_init_ram_nomigrate()
> - memory_region_init_resizeable_ram()
> - memory_region_init_ram_from_file()
>
> ... and teach qemu_ram_mmap() and qemu_anon_ram_alloc() about the flag.
> Bail out if the flag is not supported, which is the case right now for
> both, POSIX and win32. We will add Linux support next and allow specifying
> RAM_NORESERVE via memory backends.
>
> The target use case is virtio-mem, which dynamically exposes memory
> inside a large, sparse memory area to the VM.
>
> Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
--
Peter Xu
next prev parent reply other threads:[~2021-03-23 20:54 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 10:12 [PATCH v4 00/14] RAM_NORESERVE, MAP_NORESERVE and hostmem "reserve" property David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 01/14] softmmu/physmem: Mark shared anonymous memory RAM_SHARED David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 02/14] softmmu/physmem: Fix ram_block_discard_range() to handle shared anonymous memory David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 03/14] softmmu/physmem: Fix qemu_ram_remap() " David Hildenbrand
2021-03-23 20:40 ` Peter Xu
2021-03-19 10:12 ` [PATCH v4 04/14] util/mmap-alloc: Factor out calculation of the pagesize for the guard page David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 05/14] util/mmap-alloc: Factor out reserving of a memory region to mmap_reserve() David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 06/14] util/mmap-alloc: Factor out activating of memory to mmap_activate() David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 07/14] softmmu/memory: Pass ram_flags to qemu_ram_alloc_from_fd() David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 08/14] softmmu/memory: Pass ram_flags to memory_region_init_ram_shared_nomigrate() David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 09/14] util/mmap-alloc: Pass flags instead of separate bools to qemu_ram_mmap() David Hildenbrand
2021-03-23 20:49 ` Peter Xu
2021-03-25 9:40 ` David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 10/14] memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap() David Hildenbrand
2021-03-23 20:51 ` Peter Xu [this message]
2021-03-19 10:12 ` [PATCH v4 11/14] util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE under Linux David Hildenbrand
2021-03-23 20:56 ` Peter Xu
2021-03-19 10:12 ` [PATCH v4 12/14] hostmem: Wire up RAM_NORESERVE via "reserve" property David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 13/14] qmp: Include "reserve" property of memory backends David Hildenbrand
2021-03-19 15:40 ` Markus Armbruster
2021-03-19 15:49 ` David Hildenbrand
2021-03-19 16:32 ` Markus Armbruster
2021-03-19 16:40 ` David Hildenbrand
2021-03-19 10:12 ` [PATCH v4 14/14] hmp: Print "reserve" property of memory backends with "info memdev" David Hildenbrand
2021-03-25 19:00 ` Dr. David Alan Gilbert
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