From 8dbe22c6868b8a5efd1df3d0c5150524fabe61ff Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 10 May 2021 13:43:21 +0200 Subject: memory: Introduce RAM_NORESERVE and wire it up in qemu_ram_mmap() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 will do the reservation, if supported for the memory type. " 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. Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Peter Xu Acked-by: Eduardo Habkost for memory backend and machine core Signed-off-by: David Hildenbrand Message-Id: <20210510114328.21835-9-david@redhat.com> Signed-off-by: Paolo Bonzini --- migration/ram.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'migration') diff --git a/migration/ram.c b/migration/ram.c index 60ea913..723af67 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3343,8 +3343,7 @@ int colo_init_ram_cache(void) WITH_RCU_READ_LOCK_GUARD() { RAMBLOCK_FOREACH_NOT_IGNORED(block) { block->colo_cache = qemu_anon_ram_alloc(block->used_length, - NULL, - false); + NULL, false, false); if (!block->colo_cache) { error_report("%s: Can't alloc memory for COLO cache of block %s," "size 0x" RAM_ADDR_FMT, __func__, block->idstr, -- cgit v1.1