| Message ID | 1370507765-2806-3-git-send-email-pl@kamp.de |
|---|---|
| State | New |
| Headers | show |
Il 06/06/2013 10:36, Peter Lieven ha scritto: > on incoming migration do not memset pages to zero if they already read as zero. > this will allocate a new zero page and consume memory unnecessarily. even > if we madvise a MADV_DONTNEED later this will only deallocate the memory > asynchronously. > > Signed-off-by: Peter Lieven <pl@kamp.de> > --- > arch_init.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/arch_init.c b/arch_init.c > index 283081d..642f241 100644 > --- a/arch_init.c > +++ b/arch_init.c > @@ -821,14 +821,16 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) > } > > ch = qemu_get_byte(f); > - memset(host, ch, TARGET_PAGE_SIZE); > + if (ch != 0 || !is_zero_page(host)) { > + memset(host, ch, TARGET_PAGE_SIZE); > #ifndef _WIN32 > - if (ch == 0 && > - (!kvm_enabled() || kvm_has_sync_mmu()) && > - getpagesize() <= TARGET_PAGE_SIZE) { > - qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED); > - } > + if (ch == 0 && > + (!kvm_enabled() || kvm_has_sync_mmu()) && > + getpagesize() <= TARGET_PAGE_SIZE) { > + qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED); > + } > #endif > + } > } else if (flags & RAM_SAVE_FLAG_PAGE) { > void *host; > > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
On 06/19/2013 08:10 PM, Paolo Bonzini wrote: > Il 06/06/2013 10:36, Peter Lieven ha scritto: >> on incoming migration do not memset pages to zero if they already read as zero. >> this will allocate a new zero page and consume memory unnecessarily. even >> if we madvise a MADV_DONTNEED later this will only deallocate the memory >> asynchronously. >> >> Signed-off-by: Peter Lieven <pl@kamp.de> >> --- >> arch_init.c | 14 ++++++++------ >> 1 file changed, 8 insertions(+), 6 deletions(-) >> >> diff --git a/arch_init.c b/arch_init.c >> index 283081d..642f241 100644 >> --- a/arch_init.c >> +++ b/arch_init.c >> @@ -821,14 +821,16 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) >> } >> >> ch = qemu_get_byte(f); >> - memset(host, ch, TARGET_PAGE_SIZE); >> + if (ch != 0 || !is_zero_page(host)) { >> + memset(host, ch, TARGET_PAGE_SIZE); >> #ifndef _WIN32 >> - if (ch == 0 && >> - (!kvm_enabled() || kvm_has_sync_mmu()) && >> - getpagesize() <= TARGET_PAGE_SIZE) { >> - qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED); >> - } >> + if (ch == 0 && >> + (!kvm_enabled() || kvm_has_sync_mmu()) && >> + getpagesize() <= TARGET_PAGE_SIZE) { >> + qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED); >> + } >> #endif >> + } >> } else if (flags & RAM_SAVE_FLAG_PAGE) { >> void *host; >> >> > > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Is it expected to reach upstream any time soon? Thanks.
diff --git a/arch_init.c b/arch_init.c index 283081d..642f241 100644 --- a/arch_init.c +++ b/arch_init.c @@ -821,14 +821,16 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) } ch = qemu_get_byte(f); - memset(host, ch, TARGET_PAGE_SIZE); + if (ch != 0 || !is_zero_page(host)) { + memset(host, ch, TARGET_PAGE_SIZE); #ifndef _WIN32 - if (ch == 0 && - (!kvm_enabled() || kvm_has_sync_mmu()) && - getpagesize() <= TARGET_PAGE_SIZE) { - qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED); - } + if (ch == 0 && + (!kvm_enabled() || kvm_has_sync_mmu()) && + getpagesize() <= TARGET_PAGE_SIZE) { + qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED); + } #endif + } } else if (flags & RAM_SAVE_FLAG_PAGE) { void *host;
on incoming migration do not memset pages to zero if they already read as zero. this will allocate a new zero page and consume memory unnecessarily. even if we madvise a MADV_DONTNEED later this will only deallocate the memory asynchronously. Signed-off-by: Peter Lieven <pl@kamp.de> --- arch_init.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)