On Monday 03 August 2009 01:09:38 pm Izik Eidus wrote:
> Brian Jackson wrote:
> > If someone wanted to play around with ksm in qemu-kvm-0.x.x would it be
> > as simple as adding the below additions to kvm_setup_guest_memory in
> > kvm-all.c
>
> qemu-kvm-0.x.x doesnt tell me much, but if it is the function that
> register the memory than yes...
>
> (I just remember that qemu used to have something called phys_ram_base,
> in that case it would be just making madvise on phys_ram_base with the
> same of phys_ram_size....)
Sorry, I'm using qemu-kvm-0.10.6
This is what qemu_ram_alloc looks like:
/* XXX: better than nothing */
ram_addr_t qemu_ram_alloc(ram_addr_t size)
{
ram_addr_t addr;
if ((phys_ram_alloc_offset + size) > phys_ram_size) {
fprintf(stderr, "Not enough memory (requested_size = %" PRIu64 ", max
memory = %" PRIu64 ")\n",
(uint64_t)size, (uint64_t)phys_ram_size);
abort();
}
addr = phys_ram_alloc_offset;
phys_ram_alloc_offset = TARGET_PAGE_ALIGN(phys_ram_alloc_offset + size);
if (kvm_enabled())
kvm_setup_guest_memory(phys_ram_base + addr, size);
return addr;
}
And this is what my new kvm_setup_guest_memory looks like:
void kvm_setup_guest_memory(void *start, size_t size)
{
if (!kvm_has_sync_mmu()) {
#ifdef MADV_DONTFORK
int ret = madvise(start, size, MADV_DONTFORK);
if (ret) {
perror("madvice");
exit(1);
}
#else
fprintf(stderr,
"Need MADV_DONTFORK in absence of synchronous KVM MMU\n");
exit(1);
#endif
}
#ifdef MADV_MERGEABLE
madvise(start, size, MADV_MERGEABLE);
#endif
}
Look okay?
>
> > (and adding the necessary kernel changes of course)?
> >
> > On Tuesday 28 July 2009 11:39:59 am Izik Eidus wrote:
> >> This patch is not for inclusion just rfc.
> >>
> >> Thanks.
> >>
> >>
> >> From 1297b86aa257100b3d819df9f9f0932bf4f7f49d Mon Sep 17 00:00:00 2001
> >> From: Izik Eidus <[email protected]>
> >> Date: Tue, 28 Jul 2009 19:14:26 +0300
> >> Subject: [PATCH] kvm userspace: ksm support
> >>
> >> rfc for ksm support to kvm userpsace.
> >>
> >> thanks
> >>
> >> Signed-off-by: Izik Eidus <[email protected]>
> >> ---
> >> exec.c | 3 +++
> >> 1 files changed, 3 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/exec.c b/exec.c
> >> index f6d9ec9..375cc18 100644
> >> --- a/exec.c
> >> +++ b/exec.c
> >> @@ -2595,6 +2595,9 @@ ram_addr_t qemu_ram_alloc(ram_addr_t size)
> >> new_block->host = file_ram_alloc(size, mem_path);
> >> if (!new_block->host) {
> >> new_block->host = qemu_vmalloc(size);
> >> +#ifdef MADV_MERGEABLE
> >> + madvise(new_block->host, size, MADV_MERGEABLE);
> >> +#endif
> >> }
> >> new_block->offset = last_ram_offset;
> >> new_block->length = size;
>
> --
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