* Zheng Chuan (zhengch...@huawei.com) wrote: > > > On 2020/8/26 20:35, Dr. David Alan Gilbert wrote: > > * Chuan Zheng (zhengch...@huawei.com) wrote: > >> Record hash results for each sampled page, crc32 is taken to calculate > >> hash results for each sampled 4K-page. > >> > >> Signed-off-by: Chuan Zheng <zhengch...@huawei.com> > >> Signed-off-by: YanYing Zhuang <ann.zhuangyany...@huawei.com> > >> --- > >> migration/dirtyrate.c | 136 > >> ++++++++++++++++++++++++++++++++++++++++++++++++++ > >> migration/dirtyrate.h | 15 ++++++ > >> 2 files changed, 151 insertions(+) > >> > >> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c > >> index f6a94d8..66de426 100644 > >> --- a/migration/dirtyrate.c > >> +++ b/migration/dirtyrate.c > >> @@ -10,6 +10,7 @@ > >> * See the COPYING file in the top-level directory. > >> */ > >> > >> +#include <zlib.h> > >> #include "qemu/osdep.h" > >> #include "qapi/error.h" > >> #include "crypto/hash.h" > >> @@ -66,6 +67,141 @@ static void update_dirtyrate(uint64_t msec) > >> DirtyStat.dirty_rate = dirtyrate; > >> } > >> > >> +/* > >> + * get hash result for the sampled memory with length of 4K byte in > >> ramblock, > >> + * which starts from ramblock base address. > >> + */ > >> +static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info, > >> + uint64_t vfn) > >> +{ > >> + struct iovec iov_array; > >> + uint32_t crc; > >> + > >> + iov_array.iov_base = info->ramblock_addr + > >> + vfn * DIRTYRATE_SAMPLE_PAGE_SIZE; > >> + iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE; > >> + > >> + crc = crc32(0, iov_array.iov_base, iov_array.iov_len); > >> + > >> + return crc; > >> +} > >> + > >> +static int save_ramblock_hash(struct RamblockDirtyInfo *info) > >> +{ > >> + unsigned int sample_pages_count; > >> + int i; > >> + int ret = -1; > >> + GRand *rand = g_rand_new(); > >> + > >> + sample_pages_count = info->sample_pages_count; > >> + > >> + /* ramblock size less than one page, return success to skip this > >> ramblock */ > >> + if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) { > >> + ret = 0; > >> + goto out; > >> + } > >> + > >> + info->hash_result = g_try_malloc0_n(sample_pages_count, > >> + sizeof(uint32_t)); > >> + if (!info->hash_result) { > >> + ret = -1; > >> + goto out; > >> + } > >> + > >> + info->sample_page_vfn = g_try_malloc0_n(sample_pages_count, > >> + sizeof(uint64_t)); > >> + if (!info->sample_page_vfn) { > >> + g_free(info->hash_result); > >> + ret = -1; > >> + goto out; > >> + } > >> + > >> + for (i = 0; i < sample_pages_count; i++) { > >> + info->sample_page_vfn[i] = g_rand_int_range(rand, 0, > >> + info->ramblock_pages > >> - 1); > >> + info->hash_result[i] = get_ramblock_vfn_hash(info, > >> + > >> info->sample_page_vfn[i]); > >> + } > >> + ret = 0; > >> + > >> +out: > >> + g_rand_free(rand); > >> + return ret; > >> +} > >> + > >> +static void get_ramblock_dirty_info(RAMBlock *block, > >> + struct RamblockDirtyInfo *info, > >> + struct DirtyRateConfig *config) > >> +{ > >> + uint64_t sample_pages_per_gigabytes = > >> config->sample_pages_per_gigabytes; > >> + > >> + /* Right shift 30 bits to calc block size in GB */ > >> + info->sample_pages_count = (qemu_ram_get_used_length(block) * > >> + sample_pages_per_gigabytes) >> > >> + DIRTYRATE_PAGE_SHIFT_GB; > >> + > >> + /* Right shift 12 bits to calc page count in 4KB */ > >> + info->ramblock_pages = qemu_ram_get_used_length(block) >> > >> + DIRTYRATE_PAGE_SHIFT_KB; > >> + info->ramblock_addr = qemu_ram_get_host_addr(block); > >> + strcpy(info->idstr, qemu_ram_get_idstr(block)); > >> +} > >> + > >> +static struct RamblockDirtyInfo * > >> +alloc_ramblock_dirty_info(int *block_index, > >> + struct RamblockDirtyInfo *block_dinfo) > >> +{ > >> + struct RamblockDirtyInfo *info = NULL; > >> + int index = *block_index; > >> + > >> + if (!block_dinfo) { > >> + index = 0; > >> + block_dinfo = g_try_new(struct RamblockDirtyInfo, 1); > >> + } else { > >> + index++; > >> + block_dinfo = g_try_realloc(block_dinfo, (index + 1) * > >> + sizeof(struct RamblockDirtyInfo)); > >> + } > >> + if (!block_dinfo) { > >> + return NULL; > >> + } > >> + > >> + info = &block_dinfo[index]; > >> + *block_index = index; > >> + memset(info, 0, sizeof(struct RamblockDirtyInfo)); > >> + > >> + return block_dinfo; > >> +} > >> + > >> +static int record_ramblock_hash_info(struct RamblockDirtyInfo > >> **block_dinfo, > >> + struct DirtyRateConfig config, > >> + int *block_index) > >> +{ > >> + struct RamblockDirtyInfo *info = NULL; > >> + struct RamblockDirtyInfo *dinfo = NULL; > >> + RAMBlock *block = NULL; > >> + int index = 0; > >> + > >> + RAMBLOCK_FOREACH_MIGRATABLE(block) { > >> + dinfo = alloc_ramblock_dirty_info(&index, dinfo); > >> + if (dinfo == NULL) { > >> + return -1; > >> + } > >> + info = &dinfo[index]; > >> + get_ramblock_dirty_info(block, info, &config); > >> + if (save_ramblock_hash(info) < 0) { > >> + *block_dinfo = dinfo; > >> + *block_index = index; > >> + return -1; > >> + } > >> + } > >> + > >> + *block_dinfo = dinfo; > >> + *block_index = index; > >> + > >> + return 0; > >> +} > >> + > >> static void calculate_dirtyrate(struct DirtyRateConfig config) > >> { > >> /* todo */ > >> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h > >> index 8e25d93..e3adead 100644 > >> --- a/migration/dirtyrate.h > >> +++ b/migration/dirtyrate.h > >> @@ -24,6 +24,21 @@ > >> */ > >> #define RAMBLOCK_INFO_MAX_LEN 256 > >> > >> +/* > >> + * Sample page size 4K as default. > >> + */ > >> +#define DIRTYRATE_SAMPLE_PAGE_SIZE 4096 > >> + > >> +/* > >> + * Sample page size 4K shift > >> + */ > >> +#define DIRTYRATE_PAGE_SHIFT_KB 12 > >> + > >> +/* > >> + * Sample page size 1G shift > >> + */ > >> +#define DIRTYRATE_PAGE_SHIFT_GB 30 > > > > Your naming is really odd here; 'PAGE_SHIFT_KB' divides > > by 4KB, where as 'PAGE_SHIFT_GB' divices by 1KB. > > > > Simplify this; you can just do >>30 for GB because it's well known; > > you don't need a #define constant for simple KB,MB,GB since > > we all know them. > > > Hi, Dave. > Thank you for review. > OK, i will fix that in V6:) > > Also, I've asked before - do you really want 4KB explicitly - or > > should you just use TARGET_PAGE_SIZE and TARGET_PAGE_BITS ? > > > > Dave > > > TARGET_PAGE_SIZE will be 2M or 1G for HugePage. > As you see, what we get is hash result of every 'virtual' 4K-page. > We care about if it is dirty within 4K length in ramblock, which would be more > accurate than TARGET_PAGE_SIZE which could be 2M or 1G. > On the other hand, the hugepage will be broken up into 4K during migration. > > I think it is better we do hash at 'virtual' 4K-page granularity.
TARGET_PAGE_SIZE is never 2M or 1G; it's always based on the smallest MMU page on the platform; on x86 it's always 4kB; it's the unit that the migration code works in when dealing with pages. (use TARGET_PAGE_BITS to shift by). Dave > >> + > >> /* Take 1s as default for calculation duration */ > >> #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC 1 > >> > >> -- > >> 1.8.3.1 > >> > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK