qemu/include/sysemu/hostmem.h
Igor Mammedov 4ebc74dbbf hostmem: fix strict bind policy
When option -mem-prealloc is used with one or more memory-backend
objects, created backends may not obey configured bind policy or
creation may fail after kernel attempts to move pages according
to bind policy.
Reason is in file_ram_alloc(), which will pre-allocate
any descriptor based RAM if global mem_prealloc != 0 and that
happens way before bind policy is applied to memory range.

One way to fix it would be to extend memory_region_foo() API
and add more invariants that could broken later due implicit
dependencies that's hard to track.

Another approach is to drop adhoc main RAM allocation and
consolidate it around memory-backend. That allows to have
single place that allocates guest RAM (main and memdev)
in the same way and then global mem_prealloc could be
replaced by backend's property[s] that will affect created
memory-backend objects but only in correct order this time.

With main RAM now converted to hostmem backends, there is no
point in keeping global mem_prealloc around, so alias
 -mem-prealloc to "memory-backend.prealloc=on"
machine compat[*] property and make mem_prealloc a local
variable to only stir registration of compat property.

*) currently user accessible -global works only with DEVICE
   based objects and extra work is needed to make it work
   with hostmem backends. But that is convenience option
   and out of scope of this already huge refactoring.
   Hence machine compat properties were used.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20200219160953.13771-78-imammedo@redhat.com>
2020-02-19 16:50:02 +00:00

90 lines
2.4 KiB
C

/*
* QEMU Host Memory Backend
*
* Copyright (C) 2013-2014 Red Hat Inc
*
* Authors:
* Igor Mammedov <imammedo@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef SYSEMU_HOSTMEM_H
#define SYSEMU_HOSTMEM_H
#include "sysemu/numa.h"
#include "qapi/qapi-types-machine.h"
#include "qom/object.h"
#include "exec/memory.h"
#include "qemu/bitmap.h"
#define TYPE_MEMORY_BACKEND "memory-backend"
#define MEMORY_BACKEND(obj) \
OBJECT_CHECK(HostMemoryBackend, (obj), TYPE_MEMORY_BACKEND)
#define MEMORY_BACKEND_GET_CLASS(obj) \
OBJECT_GET_CLASS(HostMemoryBackendClass, (obj), TYPE_MEMORY_BACKEND)
#define MEMORY_BACKEND_CLASS(klass) \
OBJECT_CLASS_CHECK(HostMemoryBackendClass, (klass), TYPE_MEMORY_BACKEND)
/* hostmem-ram.c */
/**
* @TYPE_MEMORY_BACKEND_RAM:
* name of backend that uses mmap on the anonymous RAM
*/
#define TYPE_MEMORY_BACKEND_RAM "memory-backend-ram"
/* hostmem-file.c */
/**
* @TYPE_MEMORY_BACKEND_FILE:
* name of backend that uses mmap on a file descriptor
*/
#define TYPE_MEMORY_BACKEND_FILE "memory-backend-file"
typedef struct HostMemoryBackend HostMemoryBackend;
typedef struct HostMemoryBackendClass HostMemoryBackendClass;
/**
* HostMemoryBackendClass:
* @parent_class: opaque parent class container
*/
struct HostMemoryBackendClass {
ObjectClass parent_class;
void (*alloc)(HostMemoryBackend *backend, Error **errp);
};
/**
* @HostMemoryBackend
*
* @parent: opaque parent object container
* @size: amount of memory backend provides
* @mr: MemoryRegion representing host memory belonging to backend
* @prealloc_threads: number of threads to be used for preallocatining RAM
*/
struct HostMemoryBackend {
/* private */
Object parent;
/* protected */
uint64_t size;
bool merge, dump, use_canonical_path;
bool prealloc, is_mapped, share;
uint32_t prealloc_threads;
DECLARE_BITMAP(host_nodes, MAX_NODES + 1);
HostMemPolicy policy;
MemoryRegion mr;
};
bool host_memory_backend_mr_inited(HostMemoryBackend *backend);
MemoryRegion *host_memory_backend_get_memory(HostMemoryBackend *backend);
void host_memory_backend_set_mapped(HostMemoryBackend *backend, bool mapped);
bool host_memory_backend_is_mapped(HostMemoryBackend *backend);
size_t host_memory_backend_pagesize(HostMemoryBackend *memdev);
char *host_memory_backend_get_name(HostMemoryBackend *backend);
#endif