From patchwork Tue Jul 31 20:27:08 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Baron X-Patchwork-Id: 174328 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A4B0E2C00B1 for ; Wed, 1 Aug 2012 06:27:22 +1000 (EST) Received: from localhost ([::1]:46991 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwJ2G-0004Fu-OM for incoming@patchwork.ozlabs.org; Tue, 31 Jul 2012 16:27:20 -0400 Received: from eggs.gnu.org ([208.118.235.92]:39904) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwJ28-0004Fd-Bs for qemu-devel@nongnu.org; Tue, 31 Jul 2012 16:27:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SwJ26-0006Ap-2h for qemu-devel@nongnu.org; Tue, 31 Jul 2012 16:27:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:64827) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SwJ25-0006Ae-Qa for qemu-devel@nongnu.org; Tue, 31 Jul 2012 16:27:09 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q6VKR8SZ012640 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 31 Jul 2012 16:27:08 -0400 Received: from redhat.com (dhcp-185-114.bos.redhat.com [10.16.185.114]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id q6VKR8YE023009; Tue, 31 Jul 2012 16:27:08 -0400 Date: Tue, 31 Jul 2012 16:27:08 -0400 From: Jason Baron Message-Id: <201207312027.q6VKR8YE023009@int-mx02.intmail.prod.int.phx2.redhat.com> To: avi@redhat.com X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.132.183.28 Cc: mtosatti@redhat.com, armbru@redhat.com, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH] memory: add cmd line option to omit guest memory from qmeu core dump X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Add a new '[,dump=on|off]' option to the '-m' memory option. When 'dump=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 6 MB on a 2GB guest. Thanks to Avi Kivity for the command line syntax. Signed-off-by: Jason Baron --- exec.c | 13 +++++++++++++ osdep.h | 7 +++++++ qemu-options.hx | 11 +++++++---- sysemu.h | 1 + vl.c | 51 +++++++++++++++++++++++++++++++++++---------------- 5 files changed, 63 insertions(+), 20 deletions(-) diff --git a/exec.c b/exec.c index feb4795..75b8e23 100644 --- a/exec.c +++ b/exec.c @@ -35,6 +35,7 @@ #include "qemu-timer.h" #include "memory.h" #include "exec-memory.h" +#include "sysemu.h" #if defined(CONFIG_USER_ONLY) #include #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) @@ -2514,6 +2515,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, MemoryRegion *mr) { RAMBlock *new_block; + int ret; size = TARGET_PAGE_ALIGN(size); new_block = g_malloc0(sizeof(*new_block)); @@ -2555,6 +2557,17 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, last_ram_offset() >> TARGET_PAGE_BITS); cpu_physical_memory_set_dirty_range(new_block->offset, size, 0xff); + + /* Use MADV_DONTDUMP, if user doesn't want the guest memory in the core */ + if (dont_dump_guest) { + ret = qemu_madvise(new_block->host, size, QEMU_MADV_DONTDUMP); + if (ret) { + perror("qemu_madvise"); + fprintf(stderr, "madvise doesn't support MADV_DONTDUMP, " + "but dump=off specified\n"); + } + } + if (kvm_enabled()) kvm_setup_guest_memory(new_block->host, size); diff --git a/osdep.h b/osdep.h index 1e15a4b..e2d0f57 100644 --- a/osdep.h +++ b/osdep.h @@ -102,6 +102,11 @@ 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) @@ -109,6 +114,7 @@ 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 */ @@ -116,6 +122,7 @@ 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-options.hx b/qemu-options.hx index dc68e15..9c21b99 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -382,14 +382,17 @@ the write back by pressing @key{C-a s} (@pxref{disk_images}). ETEXI DEF("m", HAS_ARG, QEMU_OPTION_m, - "-m megs set virtual RAM size to megs MB [default=" - stringify(DEFAULT_RAM_SIZE) "]\n", QEMU_ARCH_ALL) + "-m megs[,dump=on|off]\n" + " set virtual RAM size to megs MB [default=" stringify(DEFAULT_RAM_SIZE) "]\n" + " use 'dump=off' to omit guest memory from a core dump [default=on]\n", + QEMU_ARCH_ALL) STEXI -@item -m @var{megs} +@item -m @var{megs}[,dump=on|off] @findex -m Set virtual RAM size to @var{megs} megabytes. Default is 128 MiB. Optionally, a suffix of ``M'' or ``G'' can be used to signify a value in megabytes or -gigabytes respectively. +gigabytes respectively. When 'dump=off' is specified, the guest memory is omitted +from a qemu core dump. The default is 'dump=on'. ETEXI DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, diff --git a/sysemu.h b/sysemu.h index 6540c79..f1a6f08 100644 --- a/sysemu.h +++ b/sysemu.h @@ -132,6 +132,7 @@ extern uint8_t *boot_splash_filedata; extern int boot_splash_filedata_size; extern uint8_t qemu_extra_params_fw[2]; extern QEMUClock *rtc_clock; +extern int dont_dump_guest; #define MAX_NODES 64 extern int nb_numa_nodes; diff --git a/vl.c b/vl.c index c18bb80..54ff314 100644 --- a/vl.c +++ b/vl.c @@ -226,6 +226,7 @@ int boot_menu; uint8_t *boot_splash_filedata; int boot_splash_filedata_size; uint8_t qemu_extra_params_fw[2]; +int dont_dump_guest; typedef struct FWBootEntry FWBootEntry; @@ -1041,6 +1042,38 @@ static void smp_parse(const char *optarg) max_cpus = smp_cpus; } +static void memory_parse(const char *optarg) +{ + char option[128]; + int64_t value; + char *end; + + optarg = get_opt_name(option, 128, optarg, ','); + value = strtosz(option, &end); + if (value < 0 || (*end && (*end != ','))) { + fprintf(stderr, "qemu: invalid ram size: %s\n", option); + exit(1); + } + if (value != (uint64_t)(ram_addr_t)value) { + fprintf(stderr, "qemu: ram size too large\n"); + exit(1); + } + ram_size = value; + if (*optarg == ',') { + optarg++; + } + if (get_param_value(option, 128, "dump", optarg) != 0) { + if (!strcmp(option, "on")) { + dont_dump_guest = 0; + } else if (!strcmp(option, "off")) { + dont_dump_guest = 1; + } else { + fprintf(stderr, "qemu: invalid option value '%s'\n", option); + exit(1); + } + } +} + /***********************************************************/ /* USB devices */ @@ -2650,23 +2683,9 @@ int main(int argc, char **argv, char **envp) version(); exit(0); break; - case QEMU_OPTION_m: { - int64_t value; - char *end; - - value = strtosz(optarg, &end); - if (value < 0 || *end) { - fprintf(stderr, "qemu: invalid ram size: %s\n", optarg); - exit(1); - } - - if (value != (uint64_t)(ram_addr_t)value) { - fprintf(stderr, "qemu: ram size too large\n"); - exit(1); - } - ram_size = value; + case QEMU_OPTION_m: + memory_parse(optarg); break; - } case QEMU_OPTION_mempath: mem_path = optarg; break;