[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH v8 00/15] RAM_NORESERVE, MAP_NORESERVE and hostmem "reserve" prop
From: |
David Hildenbrand |
Subject: |
[PATCH v8 00/15] RAM_NORESERVE, MAP_NORESERVE and hostmem "reserve" property |
Date: |
Mon, 10 May 2021 13:43:13 +0200 |
Based-on: 20210406080126.24010-1-david@redhat.com
Some cleanups previously sent in other context (resizeable allocations),
followed by RAM_NORESERVE, implementing it under Linux 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/shared anonymous memory
-> memory-backend-ram,id=mem0,size=10G
2) Private fd-based mappings
-> memory-backend-file,id=mem0,size=10G,mem-path=/dev/shm/0
-> memory-backend-memfd,id=mem0,size=10G
3) Private/shared hugetlb mappings
-> 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 having to set "/proc/sys/vm/overcommit_memory == 1") when using
virtio-mem and also supporting hugetlbfs in the future.
Later, upper layers are expected to specify "reserve=off" only for
memory backends assigned to virtio-mem devices, not all VM memory. To make
mistakes by users less severe, we're, for example, working on preallocation
of memory in virtio-mem itself, to be upstreamed later.
v7 -> v8:
- "hostmem: Wire up RAM_NORESERVE via "reserve" property"
-- Make the "reserve" property depend on CONFIG_LINUX
-- Add missing (since 6.1) to qom json
- "qmp: Include "reserve" property of memory backends"
-- Make the "reserve" value optional, depending on availability of the
"reserve" property
- "hmp: Print "reserve" property of memory backends with "info memdev""
-- Print only with "has_reserve"
v6 -> v7:
- Collected ACKs and RBs
- "hostmem: Wire up RAM_NORESERVE via "reserve" property"
-- Extended qapi/qom.json documentation
- "qmp: Include "reserve" property of memory backends"
-- Extended property description
v5 -> v6:
- "softmmu/memory: Pass ram_flags to memory_region_init ..."
-- Split up into two patches
---> "softmmu/memory: Pass ram_flags to memory_region.."
---> "softmmu/memory: Pass ram_flags to qemu_ram_alloc() ..."
-- Also set RAM_PREALLOC from qemu_ram_alloc_from_ptr()
- Collected acks/rbs
v4 -> v5:
- Sent out shared anonymous RAM fixes separately
- Rebased
- "hostmem: Wire up RAM_NORESERVE via "reserve" property"
-- Adjusted/simplified description of new "reserve" property
-- Properly add it to qapi/qom.json
- "qmp: Clarify memory backend properties returned via query-memdev"
-- Added
- "qmp: Include "share" property of memory backends"
-- Added
- "hmp: Print "share" property of memory backends with "info memdev""
- Added
- "qmp: Include "reserve" property of memory backends"
-- Adjust description of new "reserve" property
v3 -> v4:
- Minor comment/description updates
- "softmmu/physmem: Fix ram_block_discard_range() to handle shared ..."
-- Extended description
- "util/mmap-alloc: Pass flags instead of separate bools to ..."
-- Move flags to include/qemu/osdep.h and rename to "QEMU_MAP_*"
- "memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap()"
-- Adjust to new flags. Handle errors in mmap_activate() for now.
- "util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE under Linux"
-- Restrict support to Linux only for now
- "qmp: Include "reserve" property of memory backends"
-- Added
- "hmp: Print "reserve" property of memory backends with ..."
-- Added
v2 -> v3:
- Renamed "softmmu/physmem: Drop "shared" parameter from ram_block_add()"
to "softmmu/physmem: Mark shared anonymous memory RAM_SHARED" and
adjusted the description
- Added "softmmu/physmem: Fix ram_block_discard_range() to handle shared
anonymous memory"
- Added "softmmu/physmem: Fix qemu_ram_remap() to handle shared anonymous
memory"
- Added "util/mmap-alloc: Pass flags instead of separate bools to
qemu_ram_mmap()"
- "util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE"
-- Further tweak code comments
-- Handle shared anonymous memory
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 <peterx@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "Philippe Mathieu-Daudé" <philmd@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Cc: Greg Kurz <groug@kaod.org>
Cc: Liam Merwick <liam.merwick@oracle.com>
Cc: Marcel Apfelbaum <mapfelba@redhat.com>
Cc: Daniel P. Berrangé <berrange@redhat.com>
Cc: Michal Privoznik <mprivozn@redhat.com>
Cc: Marek Kedzierski <mkedzier@redhat.com>
David Hildenbrand (15):
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 to qemu_ram_alloc_from_fd()
softmmu/memory: Pass ram_flags to
memory_region_init_ram_shared_nomigrate()
softmmu/memory: Pass ram_flags to qemu_ram_alloc() and
qemu_ram_alloc_internal()
util/mmap-alloc: Pass flags instead of separate bools to
qemu_ram_mmap()
memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap()
util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE under Linux
hostmem: Wire up RAM_NORESERVE via "reserve" property
qmp: Clarify memory backend properties returned via query-memdev
qmp: Include "share" property of memory backends
hmp: Print "share" property of memory backends with "info memdev"
qmp: Include "reserve" property of memory backends
hmp: Print "reserve" property of memory backends with "info memdev"
backends/hostmem-file.c | 11 +-
backends/hostmem-memfd.c | 8 +-
backends/hostmem-ram.c | 7 +-
backends/hostmem.c | 36 +++
hw/core/machine-hmp-cmds.c | 6 +
hw/core/machine-qmp-cmds.c | 8 +
hw/m68k/next-cube.c | 4 +-
hw/misc/ivshmem.c | 5 +-
include/exec/cpu-common.h | 1 +
include/exec/memory.h | 42 ++--
include/exec/ram_addr.h | 9 +-
include/qemu/mmap-alloc.h | 16 +-
include/qemu/osdep.h | 30 ++-
include/sysemu/hostmem.h | 2 +-
migration/ram.c | 3 +-
qapi/machine.json | 16 +-
qapi/qom.json | 10 +
.../memory-region-housekeeping.cocci | 8 +-
softmmu/memory.c | 27 ++-
softmmu/physmem.c | 51 +++--
util/mmap-alloc.c | 212 +++++++++++++-----
util/oslib-posix.c | 7 +-
util/oslib-win32.c | 13 +-
23 files changed, 374 insertions(+), 158 deletions(-)
--
2.30.2
- [PATCH v8 00/15] RAM_NORESERVE, MAP_NORESERVE and hostmem "reserve" property,
David Hildenbrand <=
- [PATCH v8 01/15] util/mmap-alloc: Factor out calculation of the pagesize for the guard page, David Hildenbrand, 2021/05/10
- [PATCH v8 02/15] util/mmap-alloc: Factor out reserving of a memory region to mmap_reserve(), David Hildenbrand, 2021/05/10
- [PATCH v8 04/15] softmmu/memory: Pass ram_flags to qemu_ram_alloc_from_fd(), David Hildenbrand, 2021/05/10
- [PATCH v8 03/15] util/mmap-alloc: Factor out activating of memory to mmap_activate(), David Hildenbrand, 2021/05/10
- [PATCH v8 06/15] softmmu/memory: Pass ram_flags to qemu_ram_alloc() and qemu_ram_alloc_internal(), David Hildenbrand, 2021/05/10
- [PATCH v8 05/15] softmmu/memory: Pass ram_flags to memory_region_init_ram_shared_nomigrate(), David Hildenbrand, 2021/05/10
- [PATCH v8 07/15] util/mmap-alloc: Pass flags instead of separate bools to qemu_ram_mmap(), David Hildenbrand, 2021/05/10
- [PATCH v8 09/15] util/mmap-alloc: Support RAM_NORESERVE via MAP_NORESERVE under Linux, David Hildenbrand, 2021/05/10
- [PATCH v8 08/15] memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap(), David Hildenbrand, 2021/05/10
- [PATCH v8 10/15] hostmem: Wire up RAM_NORESERVE via "reserve" property, David Hildenbrand, 2021/05/10