diff options
| author | Peter Lieven <pl@kamp.de> | 2013-06-10 12:14:20 +0200 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2013-08-12 17:16:09 -0500 |
| commit | 9f60383b4173c34772251446b0ab83b5c7152f16 (patch) | |
| tree | 9be95b41ef1d514bdd9b9a8f9b4895d95baca872 | |
| parent | 64a72fa71fd2b9720c8b70726521c39bdd2c0ea9 (diff) | |
| download | qemu-9f60383b4173c34772251446b0ab83b5c7152f16.tar.gz | |
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>
(cherry picked from commit 211ea74022f51164a7729030b28eec90b6c99a08)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.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 6afc57e04c..b526dd0cb8 100644 --- a/arch_init.c +++ b/arch_init.c @@ -832,14 +832,16 @@ 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; |