OpenE2K/qemu-e2k
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memory: add -machine dump-guest-core=on|off

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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>
This commit is contained in:
Jason Baron 2012-08-02 15:44:16 -04:00 committed by Anthony Liguori
parent 3c4a4d0dcb
commit ddb97f1deb
4 changed files with 36 additions and 1 deletions
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21
exec.c
View File

@ -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;
}

7
osdep.h
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@ -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

4
qemu-config.c
View File

@ -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 */ }
},

5
qemu-options.hx
View File

@ -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