diff options
| author | Peter Lieven <pl@kamp.de> | 2013-06-10 12:14:20 +0200 |
|---|---|---|
| committer | Juan Quintela <quintela@redhat.com> | 2013-06-27 02:36:32 +0200 |
| commit | 211ea74022f51164a7729030b28eec90b6c99a08 (patch) | |
| tree | 58f143a42096d24fe5f996fe971eb92c55546be4 | |
| parent | 9ef051e5536b6368a1076046ec6c4ec4ac12b5c6 (diff) | |
migration: do not overwrite zero pages
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>
Signed-off-by: Juan Quintela <quintela@redhat.com>
| -rw-r--r-- | arch_init.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/arch_init.c b/arch_init.c index 8bb933fddb..4dd17f4ff3 100644 --- a/arch_init.c +++ b/arch_init.c @@ -835,14 +835,16 @@ 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; |