diff options
| author | Luiz Capitulino <lcapitulino@redhat.com> | 2012-09-05 16:50:16 -0300 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2012-09-17 10:18:47 -0500 |
| commit | 8490fc78e708eaaaa20f06b5efe190bfeabe0064 (patch) | |
| tree | 1c47c68f353c5d2e55a3446ba80d5b470aa46678 | |
| parent | 89c33337fd21930de671a6e34793e8b1ee257e2e (diff) | |
add -machine mem-merge=on|off option
It allows to disable memory merge support (KSM on Linux), which is
enabled by default otherwise.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
| -rw-r--r-- | exec.c | 19 | ||||
| -rw-r--r-- | qemu-config.c | 4 | ||||
| -rw-r--r-- | qemu-options.hx | 7 |
3 files changed, 26 insertions, 4 deletions
@@ -2525,6 +2525,19 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev) } } +static int memory_try_enable_merging(void *addr, size_t len) +{ + QemuOpts *opts; + + opts = qemu_opts_find(qemu_find_opts("machine"), 0); + if (opts && !qemu_opt_get_bool(opts, "mem-merge", true)) { + /* disabled by the user */ + return 0; + } + + return qemu_madvise(addr, len, QEMU_MADV_MERGEABLE); +} + ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, MemoryRegion *mr) { @@ -2544,7 +2557,7 @@ 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); + memory_try_enable_merging(new_block->host, size); } #else fprintf(stderr, "-mem-path option unsupported\n"); @@ -2559,7 +2572,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, } else { new_block->host = qemu_vmalloc(size); } - qemu_madvise(new_block->host, size, QEMU_MADV_MERGEABLE); + memory_try_enable_merging(new_block->host, size); } } new_block->length = size; @@ -2689,7 +2702,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length) length, addr); exit(1); } - qemu_madvise(vaddr, length, QEMU_MADV_MERGEABLE); + memory_try_enable_merging(vaddr, length); qemu_ram_setup_dump(vaddr, length); } return; diff --git a/qemu-config.c b/qemu-config.c index eba977ebca..12eafbb4f5 100644 --- a/qemu-config.c +++ b/qemu-config.c @@ -615,6 +615,10 @@ static QemuOptsList qemu_machine_opts = { .name = "dump-guest-core", .type = QEMU_OPT_BOOL, .help = "Include guest memory in a core dump", + }, { + .name = "mem-merge", + .type = QEMU_OPT_BOOL, + .help = "enable/disable memory merge support", }, { /* End of list */ } }, diff --git a/qemu-options.hx b/qemu-options.hx index 804a2d1739..5f96f356c3 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -38,7 +38,8 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ " supported accelerators are kvm, xen, tcg (default: tcg)\n" " kernel_irqchip=on|off controls accelerated irqchip support\n" " kvm_shadow_mem=size of KVM shadow MMU\n" - " dump-guest-core=on|off include guest memory in a core dump (default=on)\n", + " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" + " mem-merge=on|off controls memory merge support (default: on)\n", QEMU_ARCH_ALL) STEXI @item -machine [type=]@var{name}[,prop=@var{value}[,...]] @@ -57,6 +58,10 @@ Enables in-kernel irqchip support for the chosen accelerator when available. Defines the size of the KVM shadow MMU. @item dump-guest-core=on|off Include guest memory in a core dump. The default is on. +@item mem-merge=on|off +Enables or disables memory merge support. This feature, when supported by +the host, de-duplicates identical memory pages among VMs instances +(enabled by default). @end table ETEXI |