[PATCH v4 00/10] Fixed some bugs and optimized some codes for COLO

[PATCH v4 00/10] Fixed some bugs and optimized some codes for COLO

[leirao]

From: Rao, Lei <lei.rao@intel.com>

Changes since v3:
	--Remove cpu_throttle_stop from mig_throttle_counter_reset.

Changes since v2:
        --Add a function named packet_new_nocopy.
        --Continue to optimize the function of colo_flush_ram_cache.

Changes since v1:
        --Reset the state of the auto-converge counters at every checkpoint instead of directly disabling.
        --Treat the filter_send function returning zero as a normal case.

The series of patches include:
        Fixed some bugs of qemu crash.
        Optimized some code to reduce the time of checkpoint.
        Remove some unnecessary code to improve COLO.

Rao, Lei (10):
  Remove some duplicate trace code.
  Fix the qemu crash when guest shutdown during checkpoint
  Optimize the function of filter_send
  Remove migrate_set_block_enabled in checkpoint
  Add a function named packet_new_nocopy for COLO.
  Add the function of colo_compare_cleanup
  Reset the auto-converge counter at every checkpoint.
  Reduce the PVM stop time during Checkpoint
  Add the function of colo_bitmap_clear_diry.
  Fixed calculation error of pkt->header_size in fill_pkt_tcp_info()

 migration/colo.c      | 10 +++----
 migration/migration.c |  4 +++
 migration/ram.c       | 75 ++++++++++++++++++++++++++++++++++++++++++++++++---
 migration/ram.h       |  1 +
 net/colo-compare.c    | 25 ++++++++---------
 net/colo-compare.h    |  1 +
 net/colo.c            | 23 ++++++++++++++++
 net/colo.h            |  1 +
 net/filter-mirror.c   |  8 +++---
 net/filter-rewriter.c |  3 +--
 net/net.c             |  4 +++
 softmmu/runstate.c    |  1 +
 12 files changed, 127 insertions(+), 29 deletions(-)

-- 
1.8.3.1

[PATCH v4 01/10] Remove some duplicate trace code.

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

There is the same trace code in the colo_compare_packet_payload.

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
---
 net/colo-compare.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/net/colo-compare.c b/net/colo-compare.c
index 9d1ad99..c142c08 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -590,19 +590,6 @@ static int colo_packet_compare_other(Packet *spkt, Packet *ppkt)
     uint16_t offset = ppkt->vnet_hdr_len;
 
     trace_colo_compare_main("compare other");
-    if (trace_event_get_state_backends(TRACE_COLO_COMPARE_IP_INFO)) {
-        char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20];
-
-        strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src));
-        strcpy(pri_ip_dst, inet_ntoa(ppkt->ip->ip_dst));
-        strcpy(sec_ip_src, inet_ntoa(spkt->ip->ip_src));
-        strcpy(sec_ip_dst, inet_ntoa(spkt->ip->ip_dst));
-
-        trace_colo_compare_ip_info(ppkt->size, pri_ip_src,
-                                   pri_ip_dst, spkt->size,
-                                   sec_ip_src, sec_ip_dst);
-    }
-
     if (ppkt->size != spkt->size) {
         trace_colo_compare_main("Other: payload size of packets are different");
         return -1;
-- 
1.8.3.1

[PATCH v4 02/10] Fix the qemu crash when guest shutdown during checkpoint

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

This patch fixes the following:
    qemu-system-x86_64: invalid runstate transition: 'colo' ->'shutdown'
    Aborted (core dumped)

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
---
 softmmu/runstate.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/softmmu/runstate.c b/softmmu/runstate.c
index ce8977c..1564057 100644
--- a/softmmu/runstate.c
+++ b/softmmu/runstate.c
@@ -126,6 +126,7 @@ static const RunStateTransition runstate_transitions_def[] = {
     { RUN_STATE_RESTORE_VM, RUN_STATE_PRELAUNCH },
 
     { RUN_STATE_COLO, RUN_STATE_RUNNING },
+    { RUN_STATE_COLO, RUN_STATE_SHUTDOWN},
 
     { RUN_STATE_RUNNING, RUN_STATE_DEBUG },
     { RUN_STATE_RUNNING, RUN_STATE_INTERNAL_ERROR },
-- 
1.8.3.1

[PATCH v4 03/10] Optimize the function of filter_send

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

The iov_size has been calculated in filter_send(). we can directly
return the size.In this way, this is no need to repeat calculations
in filter_redirector_receive_iov();

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
---
 net/filter-mirror.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/filter-mirror.c b/net/filter-mirror.c
index f8e6500..f20240c 100644
--- a/net/filter-mirror.c
+++ b/net/filter-mirror.c
@@ -88,7 +88,7 @@ static int filter_send(MirrorState *s,
         goto err;
     }
 
-    return 0;
+    return size;
 
 err:
     return ret < 0 ? ret : -EIO;
@@ -159,7 +159,7 @@ static ssize_t filter_mirror_receive_iov(NetFilterState *nf,
     int ret;
 
     ret = filter_send(s, iov, iovcnt);
-    if (ret) {
+    if (ret < 0) {
         error_report("filter mirror send failed(%s)", strerror(-ret));
     }
 
@@ -182,10 +182,10 @@ static ssize_t filter_redirector_receive_iov(NetFilterState *nf,
 
     if (qemu_chr_fe_backend_connected(&s->chr_out)) {
         ret = filter_send(s, iov, iovcnt);
-        if (ret) {
+        if (ret < 0) {
             error_report("filter redirector send failed(%s)", strerror(-ret));
         }
-        return iov_size(iov, iovcnt);
+        return ret;
     } else {
         return 0;
     }
-- 
1.8.3.1

[PATCH v4 04/10] Remove migrate_set_block_enabled in checkpoint

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

We can detect disk migration in migrate_prepare, if disk migration
is enabled in COLO mode, we can directly report an error.and there
is no need to disable block migration at every checkpoint.

Signed-off-by: Lei Rao <lei.rao@intel.com>
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
---
 migration/colo.c      | 6 ------
 migration/migration.c | 4 ++++
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/migration/colo.c b/migration/colo.c
index de27662..1aaf316 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -435,12 +435,6 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
     if (failover_get_state() != FAILOVER_STATUS_NONE) {
         goto out;
     }
-
-    /* Disable block migration */
-    migrate_set_block_enabled(false, &local_err);
-    if (local_err) {
-        goto out;
-    }
     qemu_mutex_lock_iothread();
 
 #ifdef CONFIG_REPLICATION
diff --git a/migration/migration.c b/migration/migration.c
index ca8b97b..4578f22 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2219,6 +2219,10 @@ static bool migrate_prepare(MigrationState *s, bool blk, bool blk_inc,
     }
 
     if (blk || blk_inc) {
+        if (migrate_colo_enabled()) {
+            error_setg(errp, "No disk migration is required in COLO mode");
+            return false;
+        }
         if (migrate_use_block() || migrate_use_block_incremental()) {
             error_setg(errp, "Command options are incompatible with "
                        "current migration capabilities");
-- 
1.8.3.1

[PATCH v4 05/10] Add a function named packet_new_nocopy for COLO.

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

Use the packet_new_nocopy instead of packet_new in the
filter-rewriter module. There will be one less memory
copy in the processing of each network packet.

Signed-off-by: Lei Rao <lei.rao@intel.com>
---
 net/colo.c            | 23 +++++++++++++++++++++++
 net/colo.h            |  1 +
 net/filter-rewriter.c |  3 +--
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/net/colo.c b/net/colo.c
index ef00609..58106a8 100644
--- a/net/colo.c
+++ b/net/colo.c
@@ -174,6 +174,29 @@ Packet *packet_new(const void *data, int size, int vnet_hdr_len)
     return pkt;
 }
 
+/*
+ * packet_new_nocopy will not copy data, so the caller can't release
+ * the data. And it will be released in packet_destroy.
+ */
+Packet *packet_new_nocopy(void *data, int size, int vnet_hdr_len)
+{
+    Packet *pkt = g_slice_new(Packet);
+
+    pkt->data = data;
+    pkt->size = size;
+    pkt->creation_ms = qemu_clock_get_ms(QEMU_CLOCK_HOST);
+    pkt->vnet_hdr_len = vnet_hdr_len;
+    pkt->tcp_seq = 0;
+    pkt->tcp_ack = 0;
+    pkt->seq_end = 0;
+    pkt->header_size = 0;
+    pkt->payload_size = 0;
+    pkt->offset = 0;
+    pkt->flags = 0;
+
+    return pkt;
+}
+
 void packet_destroy(void *opaque, void *user_data)
 {
     Packet *pkt = opaque;
diff --git a/net/colo.h b/net/colo.h
index 573ab91..d91cd24 100644
--- a/net/colo.h
+++ b/net/colo.h
@@ -101,6 +101,7 @@ bool connection_has_tracked(GHashTable *connection_track_table,
                             ConnectionKey *key);
 void connection_hashtable_reset(GHashTable *connection_track_table);
 Packet *packet_new(const void *data, int size, int vnet_hdr_len);
+Packet *packet_new_nocopy(void *data, int size, int vnet_hdr_len);
 void packet_destroy(void *opaque, void *user_data);
 void packet_destroy_partial(void *opaque, void *user_data);
 
diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
index 10fe393..cb3a96c 100644
--- a/net/filter-rewriter.c
+++ b/net/filter-rewriter.c
@@ -270,8 +270,7 @@ static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
         vnet_hdr_len = nf->netdev->vnet_hdr_len;
     }
 
-    pkt = packet_new(buf, size, vnet_hdr_len);
-    g_free(buf);
+    pkt = packet_new_nocopy(buf, size, vnet_hdr_len);
 
     /*
      * if we get tcp packet
-- 
1.8.3.1

[PATCH v4 06/10] Add the function of colo_compare_cleanup

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

This patch fixes the following:
    #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
    #1  0x00007f6ae4559859 in __GI_abort () at abort.c:79
    #2  0x0000559aaa386720 in error_exit (err=16, msg=0x559aaa5973d0 <__func__.16227> "qemu_mutex_destroy") at util/qemu-thread-posix.c:36
    #3  0x0000559aaa3868c5 in qemu_mutex_destroy (mutex=0x559aabffe828) at util/qemu-thread-posix.c:69
    #4  0x0000559aaa2f93a8 in char_finalize (obj=0x559aabffe800) at chardev/char.c:285
    #5  0x0000559aaa23318a in object_deinit (obj=0x559aabffe800, type=0x559aabfd7d20) at qom/object.c:606
    #6  0x0000559aaa2331b8 in object_deinit (obj=0x559aabffe800, type=0x559aabfd9060) at qom/object.c:610
    #7  0x0000559aaa233200 in object_finalize (data=0x559aabffe800) at qom/object.c:620
    #8  0x0000559aaa234202 in object_unref (obj=0x559aabffe800) at qom/object.c:1074
    #9  0x0000559aaa2356b6 in object_finalize_child_property (obj=0x559aac0dac10, name=0x559aac778760 "compare0-0", opaque=0x559aabffe800) at qom/object.c:1584
    #10 0x0000559aaa232f70 in object_property_del_all (obj=0x559aac0dac10) at qom/object.c:557
    #11 0x0000559aaa2331ed in object_finalize (data=0x559aac0dac10) at qom/object.c:619
    #12 0x0000559aaa234202 in object_unref (obj=0x559aac0dac10) at qom/object.c:1074
    #13 0x0000559aaa2356b6 in object_finalize_child_property (obj=0x559aac0c75c0, name=0x559aac0dadc0 "chardevs", opaque=0x559aac0dac10) at qom/object.c:1584
    #14 0x0000559aaa233071 in object_property_del_child (obj=0x559aac0c75c0, child=0x559aac0dac10, errp=0x0) at qom/object.c:580
    #15 0x0000559aaa233155 in object_unparent (obj=0x559aac0dac10) at qom/object.c:599
    #16 0x0000559aaa2fb721 in qemu_chr_cleanup () at chardev/char.c:1159
    #17 0x0000559aa9f9b110 in main (argc=54, argv=0x7ffeb62fa998, envp=0x7ffeb62fab50) at vl.c:4539

When chardev is cleaned up, chr_write_lock needs to be destroyed. But
the colo-compare module is not cleaned up normally before it when the
guest poweroff. It is holding chr_write_lock at this time. This will
cause qemu crash.So we add the function of colo_compare_cleanup() before
qemu_chr_cleanup() to fix the bug.

Signed-off-by: Lei Rao <lei.rao@intel.com>
---
 net/colo-compare.c | 10 ++++++++++
 net/colo-compare.h |  1 +
 net/net.c          |  4 ++++
 3 files changed, 15 insertions(+)

diff --git a/net/colo-compare.c b/net/colo-compare.c
index c142c08..5b538f4 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -1402,6 +1402,16 @@ static void colo_compare_init(Object *obj)
                              compare_set_vnet_hdr);
 }
 
+void colo_compare_cleanup(void)
+{
+    CompareState *tmp = NULL;
+    CompareState *n = NULL;
+
+    QTAILQ_FOREACH_SAFE(tmp, &net_compares, next, n) {
+        object_unparent(OBJECT(tmp));
+    }
+}
+
 static void colo_compare_finalize(Object *obj)
 {
     CompareState *s = COLO_COMPARE(obj);
diff --git a/net/colo-compare.h b/net/colo-compare.h
index 22ddd51..b055270 100644
--- a/net/colo-compare.h
+++ b/net/colo-compare.h
@@ -20,5 +20,6 @@
 void colo_notify_compares_event(void *opaque, int event, Error **errp);
 void colo_compare_register_notifier(Notifier *notify);
 void colo_compare_unregister_notifier(Notifier *notify);
+void colo_compare_cleanup(void);
 
 #endif /* QEMU_COLO_COMPARE_H */
diff --git a/net/net.c b/net/net.c
index 725a4e1..8fcb2e7 100644
--- a/net/net.c
+++ b/net/net.c
@@ -53,6 +53,7 @@
 #include "sysemu/sysemu.h"
 #include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
+#include "net/colo-compare.h"
 #include "net/filter.h"
 #include "qapi/string-output-visitor.h"
 #include "qapi/hmp-output-visitor.h"
@@ -1463,6 +1464,9 @@ void net_cleanup(void)
 {
     NetClientState *nc;
 
+    /*cleanup colo compare module for COLO*/
+    colo_compare_cleanup();
+
     /* We may del multiple entries during qemu_del_net_client(),
      * so QTAILQ_FOREACH_SAFE() is also not safe here.
      */
-- 
1.8.3.1

[PATCH v4 07/10] Reset the auto-converge counter at every checkpoint.

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

if we don't reset the auto-converge counter,
it will continue to run with COLO running,
and eventually the system will hang due to the
CPU throttle reaching DEFAULT_MIGRATE_MAX_CPU_THROTTLE.

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/colo.c | 4 ++++
 migration/ram.c  | 9 +++++++++
 migration/ram.h  | 1 +
 3 files changed, 14 insertions(+)

diff --git a/migration/colo.c b/migration/colo.c
index 1aaf316..723ffb8 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -459,6 +459,10 @@ static int colo_do_checkpoint_transaction(MigrationState *s,
     if (ret < 0) {
         goto out;
     }
+
+    if (migrate_auto_converge()) {
+        mig_throttle_counter_reset();
+    }
     /*
      * Only save VM's live state, which not including device state.
      * TODO: We may need a timeout mechanism to prevent COLO process
diff --git a/migration/ram.c b/migration/ram.c
index 40e7895..c69a8e0 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -652,6 +652,15 @@ static void mig_throttle_guest_down(uint64_t bytes_dirty_period,
     }
 }
 
+void mig_throttle_counter_reset(void)
+{
+    RAMState *rs = ram_state;
+
+    rs->time_last_bitmap_sync = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+    rs->num_dirty_pages_period = 0;
+    rs->bytes_xfer_prev = ram_counters.transferred;
+}
+
 /**
  * xbzrle_cache_zero_page: insert a zero page in the XBZRLE cache
  *
diff --git a/migration/ram.h b/migration/ram.h
index 6378bb3..3f78175 100644
--- a/migration/ram.h
+++ b/migration/ram.h
@@ -50,6 +50,7 @@ bool ramblock_is_ignored(RAMBlock *block);
 int xbzrle_cache_resize(uint64_t new_size, Error **errp);
 uint64_t ram_bytes_remaining(void);
 uint64_t ram_bytes_total(void);
+void mig_throttle_counter_reset(void);
 
 uint64_t ram_pagesize_summary(void);
 int ram_save_queue_pages(const char *rbname, ram_addr_t start, ram_addr_t len);
-- 
1.8.3.1

[PATCH v4 08/10] Reduce the PVM stop time during Checkpoint

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

When flushing memory from ram cache to ram during every checkpoint
on secondary VM, we can copy continuous chunks of memory instead of
4096 bytes per time to reduce the time of VM stop during checkpoint.

Signed-off-by: Lei Rao <lei.rao@intel.com>
---
 migration/ram.c | 45 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 42 insertions(+), 3 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index c69a8e0..a258466 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -822,6 +822,39 @@ unsigned long migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
     return next;
 }
 
+/*
+ * colo_bitmap_find_diry:find contiguous dirty pages from start
+ *
+ * Returns the page offset within memory region of the start of the contiguout
+ * dirty page
+ *
+ * @rs: current RAM state
+ * @rb: RAMBlock where to search for dirty pages
+ * @start: page where we start the search
+ * @num: the number of contiguous dirty pages
+ */
+static inline
+unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
+                                     unsigned long start, unsigned long *num)
+{
+    unsigned long size = rb->used_length >> TARGET_PAGE_BITS;
+    unsigned long *bitmap = rb->bmap;
+    unsigned long first, next;
+
+    if (ramblock_is_ignored(rb)) {
+        return size;
+    }
+
+    first = find_next_bit(bitmap, size, start);
+    if (first >= size) {
+        return first;
+    }
+    next = find_next_zero_bit(bitmap, size, first + 1);
+    assert(next >= first);
+    *num = next - first;
+    return first;
+}
+
 static inline bool migration_bitmap_clear_dirty(RAMState *rs,
                                                 RAMBlock *rb,
                                                 unsigned long page)
@@ -3666,6 +3699,8 @@ void colo_flush_ram_cache(void)
     void *dst_host;
     void *src_host;
     unsigned long offset = 0;
+    unsigned long num = 0;
+    unsigned long i = 0;
 
     memory_global_dirty_log_sync();
     WITH_RCU_READ_LOCK_GUARD() {
@@ -3679,19 +3714,23 @@ void colo_flush_ram_cache(void)
         block = QLIST_FIRST_RCU(&ram_list.blocks);
 
         while (block) {
-            offset = migration_bitmap_find_dirty(ram_state, block, offset);
+            offset = colo_bitmap_find_dirty(ram_state, block, offset, &num);
 
             if (((ram_addr_t)offset) << TARGET_PAGE_BITS
                 >= block->used_length) {
                 offset = 0;
+                num = 0;
                 block = QLIST_NEXT_RCU(block, next);
             } else {
-                migration_bitmap_clear_dirty(ram_state, block, offset);
+                for (i = 0; i < num; i++) {
+                    migration_bitmap_clear_dirty(ram_state, block, offset + i);
+                }
                 dst_host = block->host
                          + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
                 src_host = block->colo_cache
                          + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
-                memcpy(dst_host, src_host, TARGET_PAGE_SIZE);
+                memcpy(dst_host, src_host, TARGET_PAGE_SIZE * num);
+                offset += num;
             }
         }
     }
-- 
1.8.3.1

[PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

When we use continuous dirty memory copy for flushing ram cache on
secondary VM, we can also clean up the bitmap of contiguous dirty
page memory. This also can reduce the VM stop time during checkpoint.

Signed-off-by: Lei Rao <lei.rao@intel.com>
---
 migration/ram.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index a258466..ae1e659 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -855,6 +855,30 @@ unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
     return first;
 }
 
+/**
+ * colo_bitmap_clear_dirty:when we flush ram cache to ram, we will use
+ * continuous memory copy, so we can also clean up the bitmap of contiguous
+ * dirty memory.
+ */
+static inline bool colo_bitmap_clear_dirty(RAMState *rs,
+                                           RAMBlock *rb,
+                                           unsigned long start,
+                                           unsigned long num)
+{
+    bool ret;
+    unsigned long i = 0;
+
+    qemu_mutex_lock(&rs->bitmap_mutex);
+    for (i = 0; i < num; i++) {
+        ret = test_and_clear_bit(start + i, rb->bmap);
+        if (ret) {
+            rs->migration_dirty_pages--;
+        }
+    }
+    qemu_mutex_unlock(&rs->bitmap_mutex);
+    return ret;
+}
+
 static inline bool migration_bitmap_clear_dirty(RAMState *rs,
                                                 RAMBlock *rb,
                                                 unsigned long page)
@@ -3700,7 +3724,6 @@ void colo_flush_ram_cache(void)
     void *src_host;
     unsigned long offset = 0;
     unsigned long num = 0;
-    unsigned long i = 0;
 
     memory_global_dirty_log_sync();
     WITH_RCU_READ_LOCK_GUARD() {
@@ -3722,9 +3745,7 @@ void colo_flush_ram_cache(void)
                 num = 0;
                 block = QLIST_NEXT_RCU(block, next);
             } else {
-                for (i = 0; i < num; i++) {
-                    migration_bitmap_clear_dirty(ram_state, block, offset + i);
-                }
+                colo_bitmap_clear_dirty(ram_state, block, offset, num);
                 dst_host = block->host
                          + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
                 src_host = block->colo_cache
-- 
1.8.3.1

[PATCH v4 10/10] Fixed calculation error of pkt->header_size in fill_pkt_tcp_info()

[leirao]

From: "Rao, Lei" <lei.rao@intel.com>

The data pointer has skipped vnet_hdr_len in the function of
parse_packet_early().So, we can not subtract vnet_hdr_len again
when calculating pkt->header_size in fill_pkt_tcp_info(). Otherwise,
it will cause network packet comparsion errors and greatly increase
the frequency of checkpoints.

Signed-off-by: Lei Rao <lei.rao@intel.com>
Signed-off-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>
---
 net/colo-compare.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/colo-compare.c b/net/colo-compare.c
index 5b538f4..b100e7b 100644
--- a/net/colo-compare.c
+++ b/net/colo-compare.c
@@ -211,7 +211,7 @@ static void fill_pkt_tcp_info(void *data, uint32_t *max_ack)
     pkt->tcp_ack = ntohl(tcphd->th_ack);
     *max_ack = *max_ack > pkt->tcp_ack ? *max_ack : pkt->tcp_ack;
     pkt->header_size = pkt->transport_header - (uint8_t *)pkt->data
-                       + (tcphd->th_off << 2) - pkt->vnet_hdr_len;
+                       + (tcphd->th_off << 2);
     pkt->payload_size = pkt->size - pkt->header_size;
     pkt->seq_end = pkt->tcp_seq + pkt->payload_size;
     pkt->flags = tcphd->th_flags;
-- 
1.8.3.1

Re: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.

[Dr. David Alan Gilbert]

* leirao (lei.rao@intel.com) wrote:
> From: "Rao, Lei" <lei.rao@intel.com>
> 
> When we use continuous dirty memory copy for flushing ram cache on
> secondary VM, we can also clean up the bitmap of contiguous dirty
> page memory. This also can reduce the VM stop time during checkpoint.
> 
> Signed-off-by: Lei Rao <lei.rao@intel.com>
> ---
>  migration/ram.c | 29 +++++++++++++++++++++++++----
>  1 file changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index a258466..ae1e659 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -855,6 +855,30 @@ unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
>      return first;
>  }
>  
> +/**
> + * colo_bitmap_clear_dirty:when we flush ram cache to ram, we will use
> + * continuous memory copy, so we can also clean up the bitmap of contiguous
> + * dirty memory.
> + */
> +static inline bool colo_bitmap_clear_dirty(RAMState *rs,
> +                                           RAMBlock *rb,
> +                                           unsigned long start,
> +                                           unsigned long num)
> +{
> +    bool ret;
> +    unsigned long i = 0;
> +
> +    qemu_mutex_lock(&rs->bitmap_mutex);

Please use QEMU_LOCK_GUARD(&rs->bitmap_mutex);

> +    for (i = 0; i < num; i++) {
> +        ret = test_and_clear_bit(start + i, rb->bmap);
> +        if (ret) {
> +            rs->migration_dirty_pages--;
> +        }
> +    }
> +    qemu_mutex_unlock(&rs->bitmap_mutex);
> +    return ret;

This implementation is missing the clear_bmap code that
migration_bitmap_clear_dirty has.
I think that's necessary now.

Are we sure there's any benefit in this?

Dave

> +}
> +
>  static inline bool migration_bitmap_clear_dirty(RAMState *rs,
>                                                  RAMBlock *rb,
>                                                  unsigned long page)
> @@ -3700,7 +3724,6 @@ void colo_flush_ram_cache(void)
>      void *src_host;
>      unsigned long offset = 0;
>      unsigned long num = 0;
> -    unsigned long i = 0;
>  
>      memory_global_dirty_log_sync();
>      WITH_RCU_READ_LOCK_GUARD() {
> @@ -3722,9 +3745,7 @@ void colo_flush_ram_cache(void)
>                  num = 0;
>                  block = QLIST_NEXT_RCU(block, next);
>              } else {
> -                for (i = 0; i < num; i++) {
> -                    migration_bitmap_clear_dirty(ram_state, block, offset + i);
> -                }
> +                colo_bitmap_clear_dirty(ram_state, block, offset, num);
>                  dst_host = block->host
>                           + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
>                  src_host = block->colo_cache
> -- 
> 1.8.3.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

RE: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.

[Rao, Lei]

-----Original Message-----
From: Dr. David Alan Gilbert <dgilbert@redhat.com> 
Sent: Friday, March 26, 2021 2:08 AM
To: Rao, Lei <lei.rao@intel.com>
Cc: Zhang, Chen <chen.zhang@intel.com>; lizhijian@cn.fujitsu.com; jasowang@redhat.com; quintela@redhat.com; pbonzini@redhat.com; lukasstraub2@web.de; qemu-devel@nongnu.org
Subject: Re: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.

* leirao (lei.rao@intel.com) wrote:
> From: "Rao, Lei" <lei.rao@intel.com>
> 
> When we use continuous dirty memory copy for flushing ram cache on 
> secondary VM, we can also clean up the bitmap of contiguous dirty page 
> memory. This also can reduce the VM stop time during checkpoint.
> 
> Signed-off-by: Lei Rao <lei.rao@intel.com>
> ---
>  migration/ram.c | 29 +++++++++++++++++++++++++----
>  1 file changed, 25 insertions(+), 4 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c index a258466..ae1e659 
> 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -855,6 +855,30 @@ unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
>      return first;
>  }
>  
> +/**
> + * colo_bitmap_clear_dirty:when we flush ram cache to ram, we will 
> +use
> + * continuous memory copy, so we can also clean up the bitmap of 
> +contiguous
> + * dirty memory.
> + */
> +static inline bool colo_bitmap_clear_dirty(RAMState *rs,
> +                                           RAMBlock *rb,
> +                                           unsigned long start,
> +                                           unsigned long num) {
> +    bool ret;
> +    unsigned long i = 0;
> +
> +    qemu_mutex_lock(&rs->bitmap_mutex);

Please use QEMU_LOCK_GUARD(&rs->bitmap_mutex);

Will be changed in V5. Thanks.

> +    for (i = 0; i < num; i++) {
> +        ret = test_and_clear_bit(start + i, rb->bmap);
> +        if (ret) {
> +            rs->migration_dirty_pages--;
> +        }
> +    }
> +    qemu_mutex_unlock(&rs->bitmap_mutex);
> +    return ret;

This implementation is missing the clear_bmap code that migration_bitmap_clear_dirty has.
I think that's necessary now.

Are we sure there's any benefit in this?

Dave

There is such a note about clear_bmap in struct RAMBlock:
"On destination side, this should always be NULL, and the variable `clear_bmap_shift' is meaningless."
This means that clear_bmap is always NULL on secondary VM. And for the behavior of flush ram cache to ram, we will always only happen on secondary VM.
So, I think the clear_bmap code is unnecessary for COLO.
As for the benefits, When the number of dirty pages from flush ram cache to ram is too much. it will reduce the number of locks acquired.

Lei

> +}
> +
>  static inline bool migration_bitmap_clear_dirty(RAMState *rs,
>                                                  RAMBlock *rb,
>                                                  unsigned long page) 
> @@ -3700,7 +3724,6 @@ void colo_flush_ram_cache(void)
>      void *src_host;
>      unsigned long offset = 0;
>      unsigned long num = 0;
> -    unsigned long i = 0;
>  
>      memory_global_dirty_log_sync();
>      WITH_RCU_READ_LOCK_GUARD() {
> @@ -3722,9 +3745,7 @@ void colo_flush_ram_cache(void)
>                  num = 0;
>                  block = QLIST_NEXT_RCU(block, next);
>              } else {
> -                for (i = 0; i < num; i++) {
> -                    migration_bitmap_clear_dirty(ram_state, block, offset + i);
> -                }
> +                colo_bitmap_clear_dirty(ram_state, block, offset, 
> + num);
>                  dst_host = block->host
>                           + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
>                  src_host = block->colo_cache
> --
> 1.8.3.1
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.

[Dr. David Alan Gilbert]

* Rao, Lei (lei.rao@intel.com) wrote:
> 
> -----Original Message-----
> From: Dr. David Alan Gilbert <dgilbert@redhat.com> 
> Sent: Friday, March 26, 2021 2:08 AM
> To: Rao, Lei <lei.rao@intel.com>
> Cc: Zhang, Chen <chen.zhang@intel.com>; lizhijian@cn.fujitsu.com; jasowang@redhat.com; quintela@redhat.com; pbonzini@redhat.com; lukasstraub2@web.de; qemu-devel@nongnu.org
> Subject: Re: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.
> 
> * leirao (lei.rao@intel.com) wrote:
> > From: "Rao, Lei" <lei.rao@intel.com>
> > 
> > When we use continuous dirty memory copy for flushing ram cache on 
> > secondary VM, we can also clean up the bitmap of contiguous dirty page 
> > memory. This also can reduce the VM stop time during checkpoint.
> > 
> > Signed-off-by: Lei Rao <lei.rao@intel.com>
> > ---
> >  migration/ram.c | 29 +++++++++++++++++++++++++----
> >  1 file changed, 25 insertions(+), 4 deletions(-)
> > 
> > diff --git a/migration/ram.c b/migration/ram.c index a258466..ae1e659 
> > 100644
> > --- a/migration/ram.c
> > +++ b/migration/ram.c
> > @@ -855,6 +855,30 @@ unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
> >      return first;
> >  }
> >  
> > +/**
> > + * colo_bitmap_clear_dirty:when we flush ram cache to ram, we will 
> > +use
> > + * continuous memory copy, so we can also clean up the bitmap of 
> > +contiguous
> > + * dirty memory.
> > + */
> > +static inline bool colo_bitmap_clear_dirty(RAMState *rs,
> > +                                           RAMBlock *rb,
> > +                                           unsigned long start,
> > +                                           unsigned long num) {
> > +    bool ret;
> > +    unsigned long i = 0;
> > +
> > +    qemu_mutex_lock(&rs->bitmap_mutex);
> 
> Please use QEMU_LOCK_GUARD(&rs->bitmap_mutex);
> 
> Will be changed in V5. Thanks.
> 
> > +    for (i = 0; i < num; i++) {
> > +        ret = test_and_clear_bit(start + i, rb->bmap);
> > +        if (ret) {
> > +            rs->migration_dirty_pages--;
> > +        }
> > +    }
> > +    qemu_mutex_unlock(&rs->bitmap_mutex);
> > +    return ret;
> 
> This implementation is missing the clear_bmap code that migration_bitmap_clear_dirty has.
> I think that's necessary now.
> 
> Are we sure there's any benefit in this?
> 
> Dave
> 
> There is such a note about clear_bmap in struct RAMBlock:
> "On destination side, this should always be NULL, and the variable `clear_bmap_shift' is meaningless."
> This means that clear_bmap is always NULL on secondary VM. And for the behavior of flush ram cache to ram, we will always only happen on secondary VM.
> So, I think the clear_bmap code is unnecessary for COLO.

Ah yes; can you add a comment there to note this is on the secondary
to make that clear.

> As for the benefits, When the number of dirty pages from flush ram cache to ram is too much. it will reduce the number of locks acquired.

It might be good to measure the benefit.

Dave

> Lei
> 
> > +}
> > +
> >  static inline bool migration_bitmap_clear_dirty(RAMState *rs,
> >                                                  RAMBlock *rb,
> >                                                  unsigned long page) 
> > @@ -3700,7 +3724,6 @@ void colo_flush_ram_cache(void)
> >      void *src_host;
> >      unsigned long offset = 0;
> >      unsigned long num = 0;
> > -    unsigned long i = 0;
> >  
> >      memory_global_dirty_log_sync();
> >      WITH_RCU_READ_LOCK_GUARD() {
> > @@ -3722,9 +3745,7 @@ void colo_flush_ram_cache(void)
> >                  num = 0;
> >                  block = QLIST_NEXT_RCU(block, next);
> >              } else {
> > -                for (i = 0; i < num; i++) {
> > -                    migration_bitmap_clear_dirty(ram_state, block, offset + i);
> > -                }
> > +                colo_bitmap_clear_dirty(ram_state, block, offset, 
> > + num);
> >                  dst_host = block->host
> >                           + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
> >                  src_host = block->colo_cache
> > --
> > 1.8.3.1
> > 
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

Re: [PATCH v4 08/10] Reduce the PVM stop time during Checkpoint

[Dr. David Alan Gilbert]

* leirao (lei.rao@intel.com) wrote:
> From: "Rao, Lei" <lei.rao@intel.com>
> 
> When flushing memory from ram cache to ram during every checkpoint
> on secondary VM, we can copy continuous chunks of memory instead of
> 4096 bytes per time to reduce the time of VM stop during checkpoint.
> 
> Signed-off-by: Lei Rao <lei.rao@intel.com>

A minor comment below, but :

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  migration/ram.c | 45 ++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 42 insertions(+), 3 deletions(-)
> 
> diff --git a/migration/ram.c b/migration/ram.c
> index c69a8e0..a258466 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -822,6 +822,39 @@ unsigned long migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
>      return next;
>  }
>  
> +/*
> + * colo_bitmap_find_diry:find contiguous dirty pages from start
> + *
> + * Returns the page offset within memory region of the start of the contiguout
> + * dirty page
> + *
> + * @rs: current RAM state
> + * @rb: RAMBlock where to search for dirty pages
> + * @start: page where we start the search
> + * @num: the number of contiguous dirty pages
> + */
> +static inline
> +unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
> +                                     unsigned long start, unsigned long *num)
> +{
> +    unsigned long size = rb->used_length >> TARGET_PAGE_BITS;
> +    unsigned long *bitmap = rb->bmap;
> +    unsigned long first, next;

It might be better to add the 
       *num = 0

here, which means this function always writes num

> +    if (ramblock_is_ignored(rb)) {
> +        return size;
> +    }
> +
> +    first = find_next_bit(bitmap, size, start);
> +    if (first >= size) {
> +        return first;
> +    }
> +    next = find_next_zero_bit(bitmap, size, first + 1);
> +    assert(next >= first);
> +    *num = next - first;
> +    return first;
> +}
> +
>  static inline bool migration_bitmap_clear_dirty(RAMState *rs,
>                                                  RAMBlock *rb,
>                                                  unsigned long page)
> @@ -3666,6 +3699,8 @@ void colo_flush_ram_cache(void)
>      void *dst_host;
>      void *src_host;
>      unsigned long offset = 0;
> +    unsigned long num = 0;

that could move inside the while loop.

> +    unsigned long i = 0;

This line could move inside the 'else' clause below that uses it.

>      memory_global_dirty_log_sync();
>      WITH_RCU_READ_LOCK_GUARD() {
> @@ -3679,19 +3714,23 @@ void colo_flush_ram_cache(void)
>          block = QLIST_FIRST_RCU(&ram_list.blocks);
>  
>          while (block) {
> -            offset = migration_bitmap_find_dirty(ram_state, block, offset);
> +            offset = colo_bitmap_find_dirty(ram_state, block, offset, &num);
>  
>              if (((ram_addr_t)offset) << TARGET_PAGE_BITS
>                  >= block->used_length) {
>                  offset = 0;
> +                num = 0;
>                  block = QLIST_NEXT_RCU(block, next);
>              } else {
> -                migration_bitmap_clear_dirty(ram_state, block, offset);
> +                for (i = 0; i < num; i++) {
> +                    migration_bitmap_clear_dirty(ram_state, block, offset + i);
> +                }
>                  dst_host = block->host
>                           + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
>                  src_host = block->colo_cache
>                           + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
> -                memcpy(dst_host, src_host, TARGET_PAGE_SIZE);
> +                memcpy(dst_host, src_host, TARGET_PAGE_SIZE * num);
> +                offset += num;

I was initially confused as to why the old code didn't have an offset++
but I guess that means it just checked the bit a second time that was
just cleared.

Dave


>              }
>          }
>      }
> -- 
> 1.8.3.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

RE: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.

[Rao, Lei]

The performance data has been added to the commit message in V6.

Thanks,
Lei.

-----Original Message-----
From: Dr. David Alan Gilbert <dgilbert@redhat.com> 
Sent: Monday, March 29, 2021 7:32 PM
To: Rao, Lei <lei.rao@intel.com>
Cc: Zhang, Chen <chen.zhang@intel.com>; lizhijian@cn.fujitsu.com; jasowang@redhat.com; quintela@redhat.com; pbonzini@redhat.com; lukasstraub2@web.de; qemu-devel@nongnu.org
Subject: Re: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.

* Rao, Lei (lei.rao@intel.com) wrote:
> 
> -----Original Message-----
> From: Dr. David Alan Gilbert <dgilbert@redhat.com>
> Sent: Friday, March 26, 2021 2:08 AM
> To: Rao, Lei <lei.rao@intel.com>
> Cc: Zhang, Chen <chen.zhang@intel.com>; lizhijian@cn.fujitsu.com; 
> jasowang@redhat.com; quintela@redhat.com; pbonzini@redhat.com; 
> lukasstraub2@web.de; qemu-devel@nongnu.org
> Subject: Re: [PATCH v4 09/10] Add the function of colo_bitmap_clear_diry.
> 
> * leirao (lei.rao@intel.com) wrote:
> > From: "Rao, Lei" <lei.rao@intel.com>
> > 
> > When we use continuous dirty memory copy for flushing ram cache on 
> > secondary VM, we can also clean up the bitmap of contiguous dirty 
> > page memory. This also can reduce the VM stop time during checkpoint.
> > 
> > Signed-off-by: Lei Rao <lei.rao@intel.com>
> > ---
> >  migration/ram.c | 29 +++++++++++++++++++++++++----
> >  1 file changed, 25 insertions(+), 4 deletions(-)
> > 
> > diff --git a/migration/ram.c b/migration/ram.c index 
> > a258466..ae1e659
> > 100644
> > --- a/migration/ram.c
> > +++ b/migration/ram.c
> > @@ -855,6 +855,30 @@ unsigned long colo_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
> >      return first;
> >  }
> >  
> > +/**
> > + * colo_bitmap_clear_dirty:when we flush ram cache to ram, we will 
> > +use
> > + * continuous memory copy, so we can also clean up the bitmap of 
> > +contiguous
> > + * dirty memory.
> > + */
> > +static inline bool colo_bitmap_clear_dirty(RAMState *rs,
> > +                                           RAMBlock *rb,
> > +                                           unsigned long start,
> > +                                           unsigned long num) {
> > +    bool ret;
> > +    unsigned long i = 0;
> > +
> > +    qemu_mutex_lock(&rs->bitmap_mutex);
> 
> Please use QEMU_LOCK_GUARD(&rs->bitmap_mutex);
> 
> Will be changed in V5. Thanks.
> 
> > +    for (i = 0; i < num; i++) {
> > +        ret = test_and_clear_bit(start + i, rb->bmap);
> > +        if (ret) {
> > +            rs->migration_dirty_pages--;
> > +        }
> > +    }
> > +    qemu_mutex_unlock(&rs->bitmap_mutex);
> > +    return ret;
> 
> This implementation is missing the clear_bmap code that migration_bitmap_clear_dirty has.
> I think that's necessary now.
> 
> Are we sure there's any benefit in this?
> 
> Dave
> 
> There is such a note about clear_bmap in struct RAMBlock:
> "On destination side, this should always be NULL, and the variable `clear_bmap_shift' is meaningless."
> This means that clear_bmap is always NULL on secondary VM. And for the behavior of flush ram cache to ram, we will always only happen on secondary VM.
> So, I think the clear_bmap code is unnecessary for COLO.

Ah yes; can you add a comment there to note this is on the secondary to make that clear.

> As for the benefits, When the number of dirty pages from flush ram cache to ram is too much. it will reduce the number of locks acquired.

It might be good to measure the benefit.

Dave

> Lei
> 
> > +}
> > +
> >  static inline bool migration_bitmap_clear_dirty(RAMState *rs,
> >                                                  RAMBlock *rb,
> >                                                  unsigned long page) 
> > @@ -3700,7 +3724,6 @@ void colo_flush_ram_cache(void)
> >      void *src_host;
> >      unsigned long offset = 0;
> >      unsigned long num = 0;
> > -    unsigned long i = 0;
> >  
> >      memory_global_dirty_log_sync();
> >      WITH_RCU_READ_LOCK_GUARD() {
> > @@ -3722,9 +3745,7 @@ void colo_flush_ram_cache(void)
> >                  num = 0;
> >                  block = QLIST_NEXT_RCU(block, next);
> >              } else {
> > -                for (i = 0; i < num; i++) {
> > -                    migration_bitmap_clear_dirty(ram_state, block, offset + i);
> > -                }
> > +                colo_bitmap_clear_dirty(ram_state, block, offset, 
> > + num);
> >                  dst_host = block->host
> >                           + (((ram_addr_t)offset) << TARGET_PAGE_BITS);
> >                  src_host = block->colo_cache
> > --
> > 1.8.3.1
> > 
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK