On 2012-06-27 18:49, Luiz Capitulino wrote:
> Allows to disable memory merge support (KSM on Linux), which is enabled
> by default otherwise.
>
> Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com>
> ---
> exec.c | 19 ++++++++++++++++---
> qemu-config.c | 4 ++++
> qemu-options.hx | 5 ++++-
> 3 files changed, 24 insertions(+), 4 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index 8244d54..24dd154 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -2499,6 +2499,19 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char
> *name, DeviceState *dev)
> }
> }
>
> +static int madvise_mergeable(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)
> {
> @@ -2518,7 +2531,7 @@ 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 +2558,7 @@ 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 +2685,7 @@ 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/qemu-config.c b/qemu-config.c
> index 5c3296b..e47612e 100644
> --- a/qemu-config.c
> +++ b/qemu-config.c
> @@ -595,6 +595,10 @@ static QemuOptsList qemu_machine_opts = {
> .name = "dt_compatible",
> .type = QEMU_OPT_STRING,
> .help = "Overrides the \"compatible\" property of the dt root
> node",
> + }, {
> + .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 8b66264..e0e7686 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -33,7 +33,8 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \
> " property accel=accel1[:accel2[:...]] selects
> accelerator\n"
> " 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",
> + " kvm_shadow_mem=size of KVM shadow MMU\n"
> + " mem_merge=on|off controls memory merge support
> (default: on)\n",
> QEMU_ARCH_ALL)
> STEXI
> @item -machine [type=]@var{name}[,prop=@var{value}[,...]]
> @@ -50,6 +51,8 @@ to initialize.
> Enables in-kernel irqchip support for the chosen accelerator when available.
> @item kvm_shadow_mem=size
> Defines the size of the KVM shadow MMU.
> +@item mem_merge=on|off
> +Enables or disables memory merge support (enabled by default).
Describe it as memory deduplication? Just a suggestion. Interface looks
good to me now.
Jan
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
