From 3299c593b4634d271cdeb05667de545c205f3cdb Mon Sep 17 00:00:00 2001 Message-Id: <3299c593b4634d271cdeb05667de545c205f3cdb.1350567686.git.minovotn@redhat.com> In-Reply-To: References: From: Jason Baron Date: Fri, 12 Oct 2012 19:44:33 +0200 Subject: [PATCH 7/7] memory: add -machine dump-guest-core=on|off RH-Author: Jason Baron Message-id: Patchwork-id: 43075 O-Subject: [RHEL 6.4 qemu-kvm PATCH v4 7/7] memory: add -machine dump-guest-core=on|off Bugzilla: 859447 RH-Acked-by: Markus Armbruster RH-Acked-by: Pavel Hrdina RH-Acked-by: Paolo Bonzini From: Jason Baron 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 (cherry picked from commit ddb97f1debbb6be8d871f3b565f7b8befebf0f4f) Conflicts: exec.c qemu-options.hx osdep.h qemu-config.c Added #define QEMU_MADVISE 16 for x86_64 to avoid glibc-headers dependency Call madvise() directly without wrapper, since its available in RHEL Signed-off-by: Jason Baron --- exec.c | 21 +++++++++++++++++++++ osdep.h | 4 ++++ qemu-config.c | 4 ++++ qemu-options.hx | 5 ++++- 4 files changed, 33 insertions(+), 1 deletions(-) Signed-off-by: Michal Novotny --- exec.c | 21 +++++++++++++++++++++ osdep.h | 4 ++++ qemu-config.c | 4 ++++ qemu-options.hx | 5 ++++- 4 files changed, 33 insertions(+), 1 deletion(-) diff --git a/exec.c b/exec.c index 225f19c..298d94c 100644 --- a/exec.c +++ b/exec.c @@ -2702,6 +2702,24 @@ 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 = madvise(addr, size, MADV_DONTDUMP); + if (ret) { + perror("qemu_madvise"); + fprintf(stderr, "madvise doesn't support MADV_DONTDUMP, " + "but dump_guest_core=off specified\n"); + } + } +} + ram_addr_t qemu_ram_alloc_from_ptr(DeviceState *dev, const char *name, ram_addr_t size, void *host) { @@ -2792,6 +2810,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(DeviceState *dev, const char *name, ram_list.dirty_pages += size >> TARGET_PAGE_BITS; + qemu_ram_setup_dump(new_block->host, size); + if (kvm_enabled()) kvm_setup_guest_memory(new_block->host, size); @@ -2899,6 +2919,7 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length) if (!disable_KSM) madvise(vaddr, length, MADV_MERGEABLE); #endif + qemu_ram_setup_dump(vaddr, length); } return; } diff --git a/osdep.h b/osdep.h index eae5eee..46ca087 100644 --- a/osdep.h +++ b/osdep.h @@ -90,6 +90,10 @@ # define QEMU_GNUC_PREREQ(maj, min) 0 #endif +#if defined(__x86_64__) +#define MADV_DONTDUMP 16 +#endif + void *qemu_memalign(size_t alignment, size_t size); void *qemu_vmalloc(size_t size); void qemu_vfree(void *ptr); diff --git a/qemu-config.c b/qemu-config.c index 232f984..cfadf12 100644 --- a/qemu-config.c +++ b/qemu-config.c @@ -433,6 +433,10 @@ static QemuOptsList qemu_machine_opts = { .name = "accel", .type = QEMU_OPT_STRING, .help = "accelerator list", + }, { + .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 2e47b06..4bffa74 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -1900,7 +1900,8 @@ DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ "-machine [type=]name[,prop[=value][,...]]\n" " selects emulated machine (-machine ? for list)\n" " property accel=accel1[:accel2[:...]] selects accelerator\n" - " supported accelerators are kvm, tcg (default: kvm:tcg)\n") + " supported accelerators are kvm, tcg (default: kvm:tcg)\n" + " dump-guest-core=on|off include guest memory in a core dump (default=on)\n") STEXI @item -machine [type=]@var{name}[,prop=@var{value}[,...]] @findex -machine @@ -1910,6 +1911,8 @@ available machines. Supported machine properties are: @item accel=@var{accels1}[:@var{accels2}[:...]] This is used to enable an accelerator. Depending on the target architecture, kvm or tcg can be available. By default, kvm is used if available, else tcg. +@item dump-guest-core=on|off +Include guest memory in a core dump. The default is on. @end table ETEXI -- 1.7.11.7