From 17ad9b358bceba78ae80f2963c6036eab726010c Mon Sep 17 00:00:00 2001 From: Orit Wasserman Date: Mon, 6 Aug 2012 21:42:53 +0300 Subject: Add XBZRLE to ram_save_block and ram_save_live In the outgoing migration check to see if the page is cached and changed, then send compressed page by using save_xbrle_page function. In the incoming migration check to see if RAM_SAVE_FLAG_XBZRLE is set and decompress the page (by using load_xbrle function). Signed-off-by: Benoit Hudzia Signed-off-by: Petter Svard Signed-off-by: Aidan Shribman Signed-off-by: Orit Wasserman Reviewed-by: Luiz Capitulino Reviewed-by: Eric Blake --- arch_init.c | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 156 insertions(+), 2 deletions(-) (limited to 'arch_init.c') diff --git a/arch_init.c b/arch_init.c index 60823ba..8cff9c6 100644 --- a/arch_init.c +++ b/arch_init.c @@ -43,6 +43,7 @@ #include "hw/smbios.h" #include "exec-memory.h" #include "hw/pcspk.h" +#include "qemu/page_cache.h" #ifdef DEBUG_ARCH_INIT #define DPRINTF(fmt, ...) \ @@ -104,6 +105,7 @@ const uint32_t arch_type = QEMU_ARCH; #define RAM_SAVE_FLAG_PAGE 0x08 #define RAM_SAVE_FLAG_EOS 0x10 #define RAM_SAVE_FLAG_CONTINUE 0x20 +#define RAM_SAVE_FLAG_XBZRLE 0x40 #ifdef __ALTIVEC__ #include @@ -171,6 +173,24 @@ static int is_dup_page(uint8_t *page) return 1; } +/* struct contains XBZRLE cache and a static page + used by the compression */ +static struct { + /* buffer used for XBZRLE encoding */ + uint8_t *encoded_buf; + /* buffer for storing page content */ + uint8_t *current_buf; + /* buffer used for XBZRLE decoding */ + uint8_t *decoded_buf; + /* Cache for XBZRLE */ + PageCache *cache; +} XBZRLE = { + .encoded_buf = NULL, + .current_buf = NULL, + .decoded_buf = NULL, + .cache = NULL, +}; + static void save_block_hdr(QEMUFile *f, RAMBlock *block, ram_addr_t offset, int cont, int flag) { @@ -183,6 +203,53 @@ static void save_block_hdr(QEMUFile *f, RAMBlock *block, ram_addr_t offset, } +#define ENCODING_FLAG_XBZRLE 0x1 + +static int save_xbzrle_page(QEMUFile *f, uint8_t *current_data, + ram_addr_t current_addr, RAMBlock *block, + ram_addr_t offset, int cont) +{ + int encoded_len = 0, bytes_sent = -1; + uint8_t *prev_cached_page; + + if (!cache_is_cached(XBZRLE.cache, current_addr)) { + cache_insert(XBZRLE.cache, current_addr, + g_memdup(current_data, TARGET_PAGE_SIZE)); + return -1; + } + + prev_cached_page = get_cached_data(XBZRLE.cache, current_addr); + + /* save current buffer into memory */ + memcpy(XBZRLE.current_buf, current_data, TARGET_PAGE_SIZE); + + /* XBZRLE encoding (if there is no overflow) */ + encoded_len = xbzrle_encode_buffer(prev_cached_page, XBZRLE.current_buf, + TARGET_PAGE_SIZE, XBZRLE.encoded_buf, + TARGET_PAGE_SIZE); + if (encoded_len == 0) { + DPRINTF("Skipping unmodified page\n"); + return 0; + } else if (encoded_len == -1) { + DPRINTF("Overflow\n"); + /* update data in the cache */ + memcpy(prev_cached_page, current_data, TARGET_PAGE_SIZE); + return -1; + } + + /* we need to update the data in the cache, in order to get the same data */ + memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE); + + /* Send XBZRLE based compressed page */ + save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_XBZRLE); + qemu_put_byte(f, ENCODING_FLAG_XBZRLE); + qemu_put_be16(f, encoded_len); + qemu_put_buffer(f, XBZRLE.encoded_buf, encoded_len); + bytes_sent = encoded_len + 1 + 2; + + return bytes_sent; +} + static RAMBlock *last_block; static ram_addr_t last_offset; @@ -200,6 +267,7 @@ static int ram_save_block(QEMUFile *f) ram_addr_t offset = last_offset; int bytes_sent = -1; MemoryRegion *mr; + ram_addr_t current_addr; if (!block) block = QLIST_FIRST(&ram_list.blocks); @@ -220,13 +288,24 @@ static int ram_save_block(QEMUFile *f) save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_COMPRESS); qemu_put_byte(f, *p); bytes_sent = 1; - } else { + } else if (migrate_use_xbzrle()) { + current_addr = block->offset + offset; + bytes_sent = save_xbzrle_page(f, p, current_addr, block, + offset, cont); + p = get_cached_data(XBZRLE.cache, current_addr); + } + + /* either we didn't send yet (we may have had XBZRLE overflow) */ + if (bytes_sent == -1) { save_block_hdr(f, block, offset, cont, RAM_SAVE_FLAG_PAGE); qemu_put_buffer(f, p, TARGET_PAGE_SIZE); bytes_sent = TARGET_PAGE_SIZE; } - break; + /* if page is unmodified, continue to the next */ + if (bytes_sent != 0) { + break; + } } offset += TARGET_PAGE_SIZE; @@ -304,6 +383,15 @@ static void sort_ram_list(void) static void migration_end(void) { memory_global_dirty_log_stop(); + + if (migrate_use_xbzrle()) { + cache_fini(XBZRLE.cache); + g_free(XBZRLE.cache); + g_free(XBZRLE.encoded_buf); + g_free(XBZRLE.current_buf); + g_free(XBZRLE.decoded_buf); + XBZRLE.cache = NULL; + } } static void ram_migration_cancel(void *opaque) @@ -323,6 +411,18 @@ static int ram_save_setup(QEMUFile *f, void *opaque) last_offset = 0; sort_ram_list(); + if (migrate_use_xbzrle()) { + XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() / + TARGET_PAGE_SIZE, + TARGET_PAGE_SIZE); + if (!XBZRLE.cache) { + DPRINTF("Error creating cache\n"); + return -1; + } + XBZRLE.encoded_buf = g_malloc0(TARGET_PAGE_SIZE); + XBZRLE.current_buf = g_malloc(TARGET_PAGE_SIZE); + } + /* Make sure all dirty bits are set */ QLIST_FOREACH(block, &ram_list.blocks, next) { for (addr = 0; addr < block->length; addr += TARGET_PAGE_SIZE) { @@ -438,6 +538,47 @@ static int ram_save_complete(QEMUFile *f, void *opaque) return 0; } +static int load_xbzrle(QEMUFile *f, ram_addr_t addr, void *host) +{ + int ret, rc = 0; + unsigned int xh_len; + int xh_flags; + + if (!XBZRLE.decoded_buf) { + XBZRLE.decoded_buf = g_malloc(TARGET_PAGE_SIZE); + } + + /* extract RLE header */ + xh_flags = qemu_get_byte(f); + xh_len = qemu_get_be16(f); + + if (xh_flags != ENCODING_FLAG_XBZRLE) { + fprintf(stderr, "Failed to load XBZRLE page - wrong compression!\n"); + return -1; + } + + if (xh_len > TARGET_PAGE_SIZE) { + fprintf(stderr, "Failed to load XBZRLE page - len overflow!\n"); + return -1; + } + /* load data and decode */ + qemu_get_buffer(f, XBZRLE.decoded_buf, xh_len); + + /* decode RLE */ + ret = xbzrle_decode_buffer(XBZRLE.decoded_buf, xh_len, host, + TARGET_PAGE_SIZE); + if (ret == -1) { + fprintf(stderr, "Failed to load XBZRLE page - decode error!\n"); + rc = -1; + } else if (ret > TARGET_PAGE_SIZE) { + fprintf(stderr, "Failed to load XBZRLE page - size %d exceeds %d!\n", + ret, TARGET_PAGE_SIZE); + abort(); + } + + return rc; +} + static inline void *host_from_stream_offset(QEMUFile *f, ram_addr_t offset, int flags) @@ -551,6 +692,19 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) } qemu_get_buffer(f, host, TARGET_PAGE_SIZE); + } else if (flags & RAM_SAVE_FLAG_XBZRLE) { + if (!migrate_use_xbzrle()) { + return -EINVAL; + } + void *host = host_from_stream_offset(f, addr, flags); + if (!host) { + return -EINVAL; + } + + if (load_xbzrle(f, addr, host) < 0) { + ret = -EINVAL; + goto done; + } } error = qemu_file_get_error(f); if (error) { -- cgit v1.1