From ddb97f1debbb6be8d871f3b565f7b8befebf0f4f Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Thu, 2 Aug 2012 15:44:16 -0400 Subject: memory: add -machine dump-guest-core=on|off Add a new '[,dump-guest-core=on|off]' option to the '-machine' option. When 'dump-guest-core=off' is specified, guest memory is omitted from the core dump. The default behavior continues to be to include guest memory when a core dump is triggered. In my testing, this brought the core dump size down from 384MB to 6MB on a 2GB guest. Is anything additional required to preserve this setting for migration or savevm? I don't believe so. Changelog: v3: Eliminate globals as per Anthony's suggestion set no dump from qemu_ram_remap() as well v2: move the option from -m to -machine, rename option dump -> dump-guest-core Signed-off-by: Jason Baron Signed-off-by: Anthony Liguori --- exec.c | 21 +++++++++++++++++++++ osdep.h | 7 +++++++ qemu-config.c | 4 ++++ qemu-options.hx | 5 ++++- 4 files changed, 36 insertions(+), 1 deletion(-) diff --git a/exec.c b/exec.c index 929db5cf0a..58347664b2 100644 --- a/exec.c +++ b/exec.c @@ -2475,6 +2475,24 @@ static ram_addr_t last_ram_offset(void) return last; } +static void qemu_ram_setup_dump(void *addr, ram_addr_t size) +{ + int ret; + QemuOpts *machine_opts; + + /* Use MADV_DONTDUMP, if user doesn't want the guest memory in the core */ + machine_opts = qemu_opts_find(qemu_find_opts("machine"), 0); + if (machine_opts && + !qemu_opt_get_bool(machine_opts, "dump-guest-core", true)) { + ret = qemu_madvise(addr, size, QEMU_MADV_DONTDUMP); + if (ret) { + perror("qemu_madvise"); + fprintf(stderr, "madvise doesn't support MADV_DONTDUMP, " + "but dump_guest_core=off specified\n"); + } + } +} + void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev) { RAMBlock *new_block, *block; @@ -2554,6 +2572,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, 0, size >> TARGET_PAGE_BITS); cpu_physical_memory_set_dirty_range(new_block->offset, size, 0xff); + qemu_ram_setup_dump(new_block->host, size); + if (kvm_enabled()) kvm_setup_guest_memory(new_block->host, size); @@ -2670,6 +2690,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length) exit(1); } qemu_madvise(vaddr, length, QEMU_MADV_MERGEABLE); + qemu_ram_setup_dump(vaddr, length); } return; } diff --git a/osdep.h b/osdep.h index d4b887d542..cb213e0295 100644 --- a/osdep.h +++ b/osdep.h @@ -103,6 +103,11 @@ void qemu_vfree(void *ptr); #else #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID #endif +#ifdef MADV_DONTDUMP +#define QEMU_MADV_DONTDUMP MADV_DONTDUMP +#else +#define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID +#endif #elif defined(CONFIG_POSIX_MADVISE) @@ -110,6 +115,7 @@ void qemu_vfree(void *ptr); #define QEMU_MADV_DONTNEED POSIX_MADV_DONTNEED #define QEMU_MADV_DONTFORK QEMU_MADV_INVALID #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID +#define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID #else /* no-op */ @@ -117,6 +123,7 @@ void qemu_vfree(void *ptr); #define QEMU_MADV_DONTNEED QEMU_MADV_INVALID #define QEMU_MADV_DONTFORK QEMU_MADV_INVALID #define QEMU_MADV_MERGEABLE QEMU_MADV_INVALID +#define QEMU_MADV_DONTDUMP QEMU_MADV_INVALID #endif diff --git a/qemu-config.c b/qemu-config.c index 5c3296b8c6..6700de0c71 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 = "dump-guest-core", + .type = QEMU_OPT_BOOL, + .help = "Include guest memory in a core dump", }, { /* End of list */ } }, diff --git a/qemu-options.hx b/qemu-options.hx index 47cb5bd311..6aeef6a845 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -37,7 +37,8 @@ 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" + " dump-guest-core=on|off include guest memory in a core dump (default=on)\n", QEMU_ARCH_ALL) STEXI @item -machine [type=]@var{name}[,prop=@var{value}[,...]] @@ -54,6 +55,8 @@ 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 dump-guest-core=on|off +Include guest memory in a core dump. The default is on. @end table ETEXI -- cgit v1.2.3