From 3299c593b4634d271cdeb05667de545c205f3cdb Mon Sep 17 00:00:00 2001
Message-Id: <3299c593b4634d271cdeb05667de545c205f3cdb.1350567686.git.minovotn@redhat.com>
In-Reply-To: <e8d21dedbb11e84476f54f7285e4758556f1395f.1350567686.git.minovotn@redhat.com>
References: <e8d21dedbb11e84476f54f7285e4758556f1395f.1350567686.git.minovotn@redhat.com>
From: Jason Baron <jbaron@redhat.com>
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 <jbaron@redhat.com>
Message-id: <e74c1e8ecd769f1380488d13a6b17c99a5d947d9.1350069767.git.jbaron@redhat.com>
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 <armbru@redhat.com>
RH-Acked-by: Pavel Hrdina <phrdina@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
From: Jason Baron <jbaron@redhat.com>
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 <jbaron@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
(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 <jbaron@redhat.com>
---
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 <minovotn@redhat.com>
---
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