diff options
| -rw-r--r-- | exec.c | 16 | ||||
| -rw-r--r-- | include/exec/cpu-common.h | 3 | ||||
| -rw-r--r-- | migration/postcopy-ram.c | 13 |
3 files changed, 29 insertions, 3 deletions
@@ -99,6 +99,11 @@ static MemoryRegion io_mem_unassigned; */ #define RAM_RESIZEABLE (1 << 2) +/* UFFDIO_ZEROPAGE is available on this RAMBlock to atomically + * zero the page and wake waiting processes. + * (Set during postcopy) + */ +#define RAM_UF_ZEROPAGE (1 << 3) #endif #ifdef TARGET_PAGE_BITS_VARY @@ -1767,6 +1772,17 @@ bool qemu_ram_is_shared(RAMBlock *rb) return rb->flags & RAM_SHARED; } +/* Note: Only set at the start of postcopy */ +bool qemu_ram_is_uf_zeroable(RAMBlock *rb) +{ + return rb->flags & RAM_UF_ZEROPAGE; +} + +void qemu_ram_set_uf_zeroable(RAMBlock *rb) +{ + rb->flags |= RAM_UF_ZEROPAGE; +} + /* Called with iothread lock held. */ void qemu_ram_set_idstr(RAMBlock *new_block, const char *name, DeviceState *dev) { diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h index 0d861a6289..24d335f95d 100644 --- a/include/exec/cpu-common.h +++ b/include/exec/cpu-common.h @@ -73,6 +73,9 @@ void qemu_ram_set_idstr(RAMBlock *block, const char *name, DeviceState *dev); void qemu_ram_unset_idstr(RAMBlock *block); const char *qemu_ram_get_idstr(RAMBlock *rb); bool qemu_ram_is_shared(RAMBlock *rb); +bool qemu_ram_is_uf_zeroable(RAMBlock *rb); +void qemu_ram_set_uf_zeroable(RAMBlock *rb); + size_t qemu_ram_pagesize(RAMBlock *block); size_t qemu_ram_pagesize_largest(void); diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index 032abfbf1a..a75b5d393f 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -481,6 +481,10 @@ static int ram_block_enable_notify(const char *block_name, void *host_addr, error_report("%s userfault: Region doesn't support COPY", __func__); return -1; } + if (reg_struct.ioctls & ((__u64)1 << _UFFDIO_ZEROPAGE)) { + RAMBlock *rb = qemu_ram_block_by_name(block_name); + qemu_ram_set_uf_zeroable(rb); + } return 0; } @@ -700,11 +704,14 @@ int postcopy_place_page(MigrationIncomingState *mis, void *host, void *from, int postcopy_place_page_zero(MigrationIncomingState *mis, void *host, RAMBlock *rb) { + size_t pagesize = qemu_ram_pagesize(rb); trace_postcopy_place_page_zero(host); - if (qemu_ram_pagesize(rb) == getpagesize()) { - if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, NULL, getpagesize(), - rb)) { + /* Normal RAMBlocks can zero a page using UFFDIO_ZEROPAGE + * but it's not available for everything (e.g. hugetlbpages) + */ + if (qemu_ram_is_uf_zeroable(rb)) { + if (qemu_ufd_copy_ioctl(mis->userfault_fd, host, NULL, pagesize, rb)) { int e = errno; error_report("%s: %s zero host: %p", __func__, strerror(e), host); |