From a55bbe31873a5014fa6457c936858f11e2d22b32 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Fri, 25 Jun 2010 11:10:05 -0600 Subject: [PATCH] savevm: Create a new continue flag to avoid resending block name Allows us to compress the protocol a bit by setting a flag on the offset which indicates we're still working within the same block as last time. That way we can avoid sending the block name for every page. Suggested by Anthony Liguori. Signed-off-by: Alex Williamson Signed-off-by: Anthony Liguori --- arch_init.c | 94 ++++++++++++++++++++++++++++++++----------------------------- 1 file changed, 50 insertions(+), 44 deletions(-) diff --git a/arch_init.c b/arch_init.c index 186645b..2f082f3 100644 --- a/arch_init.c +++ b/arch_init.c @@ -87,6 +87,7 @@ const uint32_t arch_type = QEMU_ARCH; #define RAM_SAVE_FLAG_MEM_SIZE 0x04 #define RAM_SAVE_FLAG_PAGE 0x08 #define RAM_SAVE_FLAG_EOS 0x10 +#define RAM_SAVE_FLAG_CONTINUE 0x20 static int is_dup_page(uint8_t *page, uint8_t ch) { @@ -120,6 +121,7 @@ static int ram_save_block(QEMUFile *f) do { if (cpu_physical_memory_get_dirty(current_addr, MIGRATION_DIRTY_FLAG)) { uint8_t *p; + int cont = (block == last_block) ? RAM_SAVE_FLAG_CONTINUE : 0; cpu_physical_memory_reset_dirty(current_addr, current_addr + TARGET_PAGE_SIZE, @@ -128,17 +130,21 @@ static int ram_save_block(QEMUFile *f) p = block->host + offset; if (is_dup_page(p, *p)) { - qemu_put_be64(f, offset | RAM_SAVE_FLAG_COMPRESS); - qemu_put_byte(f, strlen(block->idstr)); - qemu_put_buffer(f, (uint8_t *)block->idstr, - strlen(block->idstr)); + qemu_put_be64(f, offset | cont | RAM_SAVE_FLAG_COMPRESS); + if (!cont) { + qemu_put_byte(f, strlen(block->idstr)); + qemu_put_buffer(f, (uint8_t *)block->idstr, + strlen(block->idstr)); + } qemu_put_byte(f, *p); bytes_sent = 1; } else { - qemu_put_be64(f, offset | RAM_SAVE_FLAG_PAGE); - qemu_put_byte(f, strlen(block->idstr)); - qemu_put_buffer(f, (uint8_t *)block->idstr, - strlen(block->idstr)); + qemu_put_be64(f, offset | cont | RAM_SAVE_FLAG_PAGE); + if (!cont) { + qemu_put_byte(f, strlen(block->idstr)); + qemu_put_buffer(f, (uint8_t *)block->idstr, + strlen(block->idstr)); + } qemu_put_buffer(f, p, TARGET_PAGE_SIZE); bytes_sent = TARGET_PAGE_SIZE; } @@ -289,6 +295,36 @@ int ram_save_live(Monitor *mon, QEMUFile *f, int stage, void *opaque) return (stage == 2) && (expected_time <= migrate_max_downtime()); } +static inline void *host_from_stream_offset(QEMUFile *f, + ram_addr_t offset, + int flags) +{ + static RAMBlock *block = NULL; + char id[256]; + uint8_t len; + + if (flags & RAM_SAVE_FLAG_CONTINUE) { + if (!block) { + fprintf(stderr, "Ack, bad migration stream!\n"); + return NULL; + } + + return block->host + offset; + } + + len = qemu_get_byte(f); + qemu_get_buffer(f, (uint8_t *)id, len); + id[len] = 0; + + QLIST_FOREACH(block, &ram_list.blocks, next) { + if (!strncmp(id, block->idstr, sizeof(id))) + return block->host + offset; + } + + fprintf(stderr, "Can't find block %s!\n", id); + return NULL; +} + int ram_load(QEMUFile *f, void *opaque, int version_id) { ram_addr_t addr; @@ -346,26 +382,11 @@ int ram_load(QEMUFile *f, void *opaque, int version_id) void *host; uint8_t ch; - if (version_id == 3) { + if (version_id == 3) host = qemu_get_ram_ptr(addr); - } else { - RAMBlock *block; - char id[256]; - uint8_t len; - - len = qemu_get_byte(f); - qemu_get_buffer(f, (uint8_t *)id, len); - id[len] = 0; + else + host = host_from_stream_offset(f, addr, flags); - QLIST_FOREACH(block, &ram_list.blocks, next) { - if (!strncmp(id, block->idstr, sizeof(id))) - break; - } - if (!block) - return -EINVAL; - - host = block->host + addr; - } ch = qemu_get_byte(f); memset(host, ch, TARGET_PAGE_SIZE); #ifndef _WIN32 @@ -377,26 +398,11 @@ int ram_load(QEMUFile *f, void *opaque, int version_id) } else if (flags & RAM_SAVE_FLAG_PAGE) { void *host; - if (version_id == 3) { + if (version_id == 3) host = qemu_get_ram_ptr(addr); - } else { - RAMBlock *block; - char id[256]; - uint8_t len; + else + host = host_from_stream_offset(f, addr, flags); - len = qemu_get_byte(f); - qemu_get_buffer(f, (uint8_t *)id, len); - id[len] = 0; - - QLIST_FOREACH(block, &ram_list.blocks, next) { - if (!strncmp(id, block->idstr, sizeof(id))) - break; - } - if (!block) - return -EINVAL; - - host = block->host + addr; - } qemu_get_buffer(f, host, TARGET_PAGE_SIZE); } if (qemu_file_has_error(f)) { -- 2.7.4