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Re: [PATCH v7 06/12] migration/dirtyrate: Record hash results for each s
From: |
Li Qiang |
Subject: |
Re: [PATCH v7 06/12] migration/dirtyrate: Record hash results for each sampled page |
Date: |
Mon, 14 Sep 2020 19:25:26 +0800 |
Zheng Chuan <zhengchuan@huawei.com> 于2020年9月13日周日 上午10:59写道:
>
>
>
> On 2020/9/10 21:51, Li Qiang wrote:
> > Chuan Zheng <zhengchuan@huawei.com> 于2020年9月9日周三 下午10:14写道:
> >>
> >> Record hash results for each sampled page, crc32 is taken to calculate
> >> hash results for each sampled length in TARGET_PAGE_SIZE.
> >>
> >> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> >> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
> >> Reviewed-by: David Edmondson <david.edmondson@oracle.com>
> >> ---
> >> migration/dirtyrate.c | 125
> >> ++++++++++++++++++++++++++++++++++++++++++++++++++
> >> 1 file changed, 125 insertions(+)
> >>
> >> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> >> index d56cd93..bc87269 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 "cpu.h"
> >> @@ -68,6 +69,130 @@ static void update_dirtyrate(uint64_t msec)
> >> DirtyStat.dirty_rate = dirtyrate;
> >> }
> >>
> >> +/*
> >> + * get hash result for the sampled memory with length of TARGET_PAGE_SIZE
> >> + * in ramblock, which starts from ramblock base address.
> >> + */
> >> +static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
> >> + uint64_t vfn)
> >> +{
> >> + uint32_t crc;
> >> +
> >> + crc = crc32(0, (info->ramblock_addr +
> >> + vfn * TARGET_PAGE_SIZE), TARGET_PAGE_SIZE);
> >> +
> >> + return crc;
> >> +}
> >> +
> >> +static int save_ramblock_hash(struct RamblockDirtyInfo *info)
> >> +{
> >> + unsigned int sample_pages_count;
> >> + int i;
> >> + GRand *rand;
> >> +
> >> + 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)) {
> >> + return 0;
> >> + }
> >> +
> >> + info->hash_result = g_try_malloc0_n(sample_pages_count,
> >> + sizeof(uint32_t));
> >> + if (!info->hash_result) {
> >> + return -1;
> >> + }
> >> +
> >> + info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
> >> + sizeof(uint64_t));
> >> + if (!info->sample_page_vfn) {
> >> + g_free(info->hash_result);
> >> + return -1;
> >> + }
> >> +
> >> + rand = g_rand_new();
> >> + 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]);
> >> + }
> >> + g_rand_free(rand);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> +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 ramblock size in GB */
> >> + info->sample_pages_count = (qemu_ram_get_used_length(block) *
> >> + sample_pages_per_gigabytes) >> 30;
> >> + /* Right shift TARGET_PAGE_BITS to calc page count */
> >> + info->ramblock_pages = qemu_ram_get_used_length(block) >>
> >> + TARGET_PAGE_BITS;
> >> + 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;
> >
> > What if this case happens the 'index' has been increased? but the
> > allocation is failed.
> >
> >> + }
> >> +
> >> + 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);
> >
> > Here for every migratable block, you call 'alloc_ramblock_dirty_info'.
> > This also complicates the 'alloc_ramblock_dirty_info' itself as:
> > 1. you need to differentiate the first and other element.
> > 2. you need to use two out parameter which seems can make confusion.
> >
> > Could we allocates this array at onetime. This maybe two iteration
> > the ram block list.
> > But I think may make the code more simple and clean.
> >
> > Thank,s
> > Li Qiang
> >
> Hi, Qiang.
> Thank you for your review.
> I am not sure if i fully understand what's you mean:)
> You mean we first record total index by first iteration
> the ram block list and allocate array at onetime?
Hi Chuan,
Yes, this is what I mean.
I have just see your new patches, will review asap.
Thanks,
Li Qiang
>
> >> + 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;
> >
> > As the first comment, here 'index' seems not right?
> >
> >
> > Thanks,
> > Li Qiang
> >> + return -1;
> >> + }
> >> + }
> >> +
> >> + *block_dinfo = dinfo;
> >> + *block_index = index;
> >> +
> >> + return 0;
> >> +}
> >> +
> >> static void calculate_dirtyrate(struct DirtyRateConfig config)
> >> {
> >> /* todo */
> >> --
> >> 1.8.3.1
> >>
> >>
> >
> > .
> >