Allow for disabling memory merge support (KSM on Linux), which is enabled by default otherwise.
Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com> --- cpu-all.h | 1 + exec-obsolete.h | 1 + exec.c | 25 +++++++++++++++++++++---- memory.c | 5 +++++ memory.h | 5 +++++ qemu-options.hx | 7 +++++++ vl.c | 3 +++ 7 files changed, 43 insertions(+), 4 deletions(-) diff --git a/cpu-all.h b/cpu-all.h index 9dc249a..429c1c3 100644 --- a/cpu-all.h +++ b/cpu-all.h @@ -484,6 +484,7 @@ typedef struct RAMBlock { } RAMBlock; typedef struct RAMList { + bool merge_memory; uint8_t *phys_dirty; QLIST_HEAD(, RAMBlock) blocks; } RAMList; diff --git a/exec-obsolete.h b/exec-obsolete.h index 792c831..71faf81 100644 --- a/exec-obsolete.h +++ b/exec-obsolete.h @@ -30,6 +30,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, ram_addr_t qemu_ram_alloc(ram_addr_t size, MemoryRegion *mr); void qemu_ram_free(ram_addr_t addr); void qemu_ram_free_from_ptr(ram_addr_t addr); +void qemu_set_mem_merge(bool value); struct MemoryRegion; struct MemoryRegionSection; diff --git a/exec.c b/exec.c index 8244d54..c003789 100644 --- a/exec.c +++ b/exec.c @@ -112,7 +112,10 @@ static uint8_t *code_gen_ptr; int phys_ram_fd; static int in_migration; -RAMList ram_list = { .blocks = QLIST_HEAD_INITIALIZER(ram_list.blocks) }; +RAMList ram_list = { + .merge_memory = true, + .blocks = QLIST_HEAD_INITIALIZER(ram_list.blocks) +}; static MemoryRegion *system_memory; static MemoryRegion *system_io; @@ -2499,6 +2502,20 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev) } } +void qemu_set_mem_merge(bool value) +{ + ram_list.merge_memory = value; +} + +static int madvise_mergeable(void *addr, size_t len) +{ + if (ram_list.merge_memory) { + return qemu_madvise(addr, len, QEMU_MADV_MERGEABLE); + } + + return -1; +} + ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, MemoryRegion *mr) { @@ -2518,7 +2535,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, new_block->host = file_ram_alloc(new_block, size, mem_path); if (!new_block->host) { new_block->host = qemu_vmalloc(size); - qemu_madvise(new_block->host, size, QEMU_MADV_MERGEABLE); + madvise_mergeable(new_block->host, size); } #else fprintf(stderr, "-mem-path option unsupported\n"); @@ -2545,7 +2562,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, new_block->host = qemu_vmalloc(size); } #endif - qemu_madvise(new_block->host, size, QEMU_MADV_MERGEABLE); + madvise_mergeable(new_block->host, size); } } new_block->length = size; @@ -2672,7 +2689,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length) length, addr); exit(1); } - qemu_madvise(vaddr, length, QEMU_MADV_MERGEABLE); + madvise_mergeable(vaddr, length); } return; } diff --git a/memory.c b/memory.c index aab4a31..71789ab 100644 --- a/memory.c +++ b/memory.c @@ -1439,6 +1439,11 @@ void memory_global_dirty_log_stop(void) MEMORY_LISTENER_CALL_GLOBAL(log_global_stop, Reverse); } +void memory_global_set_merge(bool value) +{ + qemu_set_mem_merge(value); +} + static void listener_add_address_space(MemoryListener *listener, AddressSpace *as) { diff --git a/memory.h b/memory.h index 740c48e..ac224d4 100644 --- a/memory.h +++ b/memory.h @@ -746,6 +746,11 @@ void memory_global_dirty_log_start(void); */ void memory_global_dirty_log_stop(void); +/** + * memory_global_set_merge: enable/disable memory merging done by the host + */ +void memory_global_set_merge(bool value); + void mtree_info(fprintf_function mon_printf, void *f); #endif diff --git a/qemu-options.hx b/qemu-options.hx index 8b66264..324cc97 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -409,6 +409,13 @@ Preallocate memory when using -mem-path. ETEXI #endif +DEF("disable-mem-merge", 0, QEMU_OPTION_disable_mem_merge, + "-disable-mem-merge disable memory merging.", QEMU_ARCH_ALL) +STEXI +@item -disable-mem-merge +Disable memory merging. On Linux systems this disables KSM support. +ETEXI + DEF("k", HAS_ARG, QEMU_OPTION_k, "-k language use keyboard layout (for example 'fr' for French)\n", QEMU_ARCH_ALL) diff --git a/vl.c b/vl.c index 1329c30..f81aadf 100644 --- a/vl.c +++ b/vl.c @@ -2676,6 +2676,9 @@ int main(int argc, char **argv, char **envp) mem_prealloc = 1; break; #endif + case QEMU_OPTION_disable_mem_merge: + memory_global_set_merge(false); + break; case QEMU_OPTION_d: log_mask = optarg; break; -- 1.7.10.2.565.gbd578b5