[Qemu-devel] [PULL 0/4] migration queue

[Qemu-devel] [PULL 0/4] migration queue

[Juan Quintela]

The following changes since commit f53f3d0a00b6df39ce8dfca942608e5b6a9a4f71:

  Merge remote-tracking branch 'remotes/kvaneesh/for-upstream' into staging (2014-03-08 12:38:43 +0000)

are available in the git repository at:


  git://github.com/juanquintela/qemu.git tags/migration/20140308-1

for you to fetch changes up to 464400f6a5583eafb466595add435a3a33ea980f:

  migration: extend section_start/end traces (2014-03-08 22:22:34 +0100)

----------------------------------------------------------------
migration/next for 20140308

----------------------------------------------------------------
Alexey Kardashevskiy (2):
      vl: add system_wakeup_request tracepoint
      migration: extend section_start/end traces

Gonglei (1):
      XBZRLE: Fix qemu crash when resize the xbzrle cache

Markus Armbruster (1):
      qemu_file: Fix mismerge of "use fwrite() correctly"

 arch_init.c  | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 qemu-file.c  |  2 +-
 savevm.c     | 12 ++++++------
 trace-events |  5 +++--
 vl.c         |  2 ++
 5 files changed, 61 insertions(+), 12 deletions(-)

[Qemu-devel] [PATCH 1/4] XBZRLE: Fix qemu crash when resize the xbzrle cache

[Juan Quintela]

From: Gonglei <arei.gonglei@huawei.com>

Resizing the xbzrle cache during migration causes qemu-crash,
because the main-thread and migration-thread modify the xbzrle
cache size concurrently without lock-protection.

Signed-off-by: ChenLiang <chenliang88@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 arch_init.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index fe17279..60c975d 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -164,8 +164,9 @@ static struct {
     uint8_t *encoded_buf;
     /* buffer for storing page content */
     uint8_t *current_buf;
-    /* Cache for XBZRLE */
+    /* Cache for XBZRLE, Protected by lock. */
     PageCache *cache;
+    QemuMutex lock;
 } XBZRLE = {
     .encoded_buf = NULL,
     .current_buf = NULL,
@@ -174,16 +175,52 @@ static struct {
 /* buffer used for XBZRLE decoding */
 static uint8_t *xbzrle_decoded_buf;

+static void XBZRLE_cache_lock(void)
+{
+    if (migrate_use_xbzrle())
+        qemu_mutex_lock(&XBZRLE.lock);
+}
+
+static void XBZRLE_cache_unlock(void)
+{
+    if (migrate_use_xbzrle())
+        qemu_mutex_unlock(&XBZRLE.lock);
+}
+
 int64_t xbzrle_cache_resize(int64_t new_size)
 {
+    PageCache *new_cache, *cache_to_free;
+
     if (new_size < TARGET_PAGE_SIZE) {
         return -1;
     }

+    /* no need to lock, the current thread holds qemu big lock */
     if (XBZRLE.cache != NULL) {
-        return cache_resize(XBZRLE.cache, new_size / TARGET_PAGE_SIZE) *
-            TARGET_PAGE_SIZE;
+        /* check XBZRLE.cache again later */
+        if (pow2floor(new_size) == migrate_xbzrle_cache_size()) {
+            return pow2floor(new_size);
+        }
+        new_cache = cache_init(new_size / TARGET_PAGE_SIZE,
+                                        TARGET_PAGE_SIZE);
+        if (!new_cache) {
+            DPRINTF("Error creating cache\n");
+            return -1;
+        }
+
+        XBZRLE_cache_lock();
+        /* the XBZRLE.cache may have be destroyed, check it again */
+        if (XBZRLE.cache != NULL) {
+            cache_to_free = XBZRLE.cache;
+            XBZRLE.cache = new_cache;
+        } else {
+            cache_to_free = new_cache;
+        }
+        XBZRLE_cache_unlock();
+
+        cache_fini(cache_to_free);
     }
+
     return pow2floor(new_size);
 }

@@ -539,6 +576,8 @@ static int ram_save_block(QEMUFile *f, bool last_stage)
             ret = ram_control_save_page(f, block->offset,
                                offset, TARGET_PAGE_SIZE, &bytes_sent);

+            XBZRLE_cache_lock();
+
             current_addr = block->offset + offset;
             if (ret != RAM_SAVE_CONTROL_NOT_SUPP) {
                 if (ret != RAM_SAVE_CONTROL_DELAYED) {
@@ -587,6 +626,7 @@ static int ram_save_block(QEMUFile *f, bool last_stage)
                 acct_info.norm_pages++;
             }

+            XBZRLE_cache_unlock();
             /* if page is unmodified, continue to the next */
             if (bytes_sent > 0) {
                 last_sent_block = block;
@@ -654,6 +694,7 @@ static void migration_end(void)
         migration_bitmap = NULL;
     }

+    XBZRLE_cache_lock();
     if (XBZRLE.cache) {
         cache_fini(XBZRLE.cache);
         g_free(XBZRLE.cache);
@@ -663,6 +704,7 @@ static void migration_end(void)
         XBZRLE.encoded_buf = NULL;
         XBZRLE.current_buf = NULL;
     }
+    XBZRLE_cache_unlock();
 }

 static void ram_migration_cancel(void *opaque)
@@ -693,13 +735,17 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
     dirty_rate_high_cnt = 0;

     if (migrate_use_xbzrle()) {
+        qemu_mutex_lock_iothread();
         XBZRLE.cache = cache_init(migrate_xbzrle_cache_size() /
                                   TARGET_PAGE_SIZE,
                                   TARGET_PAGE_SIZE);
         if (!XBZRLE.cache) {
+            qemu_mutex_unlock_iothread();
             DPRINTF("Error creating cache\n");
             return -1;
         }
+        qemu_mutex_init(&XBZRLE.lock);
+        qemu_mutex_unlock_iothread();

         /* We prefer not to abort if there is no memory */
         XBZRLE.encoded_buf = g_try_malloc0(TARGET_PAGE_SIZE);
-- 
1.8.5.3

[Qemu-devel] [PATCH 2/4] qemu_file: Fix mismerge of "use fwrite() correctly"

[Juan Quintela]

From: Markus Armbruster <armbru@redhat.com>

Reviewers accepted v2 of the patch, but what got committed was v1,
with the R-bys for v2.  This is the v1->v2 followup fix.

[Amit:
 This fixes commit aded6539d983280212e08d09f14157b1cb4d58cc
]

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 qemu-file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/qemu-file.c b/qemu-file.c
index f074af1..e5ec798 100644
--- a/qemu-file.c
+++ b/qemu-file.c
@@ -105,7 +105,7 @@ static int stdio_put_buffer(void *opaque, const uint8_t *buf, int64_t pos,
     res = fwrite(buf, 1, size, s->stdio_file);

     if (res != size) {
-        return -EIO;	/* fake errno value */
+        return -errno;
     }
     return res;
 }
-- 
1.8.5.3

[Qemu-devel] [PATCH 3/4] vl: add system_wakeup_request tracepoint

[Juan Quintela]

From: Alexey Kardashevskiy <aik@ozlabs.ru>

It might be useful for tracing migration.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 trace-events | 1 +
 vl.c         | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/trace-events b/trace-events
index aec4202..466c27e 100644
--- a/trace-events
+++ b/trace-events
@@ -486,6 +486,7 @@ runstate_set(int new_state) "new state %d"
 g_malloc(size_t size, void *ptr) "size %zu ptr %p"
 g_realloc(void *ptr, size_t size, void *newptr) "ptr %p size %zu newptr %p"
 g_free(void *ptr) "ptr %p"
+system_wakeup_request(int reason) "reason=%d"

 # block/qcow2.c
 qcow2_writev_start_req(void *co, int64_t sector, int nb_sectors) "co %p sector %" PRIx64 " nb_sectors %d"
diff --git a/vl.c b/vl.c
index 41581c1..50693e6 100644
--- a/vl.c
+++ b/vl.c
@@ -1837,6 +1837,8 @@ void qemu_register_suspend_notifier(Notifier *notifier)

 void qemu_system_wakeup_request(WakeupReason reason)
 {
+    trace_system_wakeup_request(reason);
+
     if (!runstate_check(RUN_STATE_SUSPENDED)) {
         return;
     }
-- 
1.8.5.3

[Qemu-devel] [PATCH 4/4] migration: extend section_start/end traces

[Juan Quintela]

From: Alexey Kardashevskiy <aik@ozlabs.ru>

This adds @idstr to savevm_section_start and savevm_section_end
tracepoints.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 savevm.c     | 12 ++++++------
 trace-events |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/savevm.c b/savevm.c
index 7329fc5..d094fbb 100644
--- a/savevm.c
+++ b/savevm.c
@@ -527,13 +527,13 @@ int qemu_savevm_state_iterate(QEMUFile *f)
         if (qemu_file_rate_limit(f)) {
             return 0;
         }
-        trace_savevm_section_start();
+        trace_savevm_section_start(se->idstr, se->section_id);
         /* Section type */
         qemu_put_byte(f, QEMU_VM_SECTION_PART);
         qemu_put_be32(f, se->section_id);

         ret = se->ops->save_live_iterate(f, se->opaque);
-        trace_savevm_section_end(se->section_id);
+        trace_savevm_section_end(se->idstr, se->section_id);

         if (ret < 0) {
             qemu_file_set_error(f, ret);
@@ -565,13 +565,13 @@ void qemu_savevm_state_complete(QEMUFile *f)
                 continue;
             }
         }
-        trace_savevm_section_start();
+        trace_savevm_section_start(se->idstr, se->section_id);
         /* Section type */
         qemu_put_byte(f, QEMU_VM_SECTION_END);
         qemu_put_be32(f, se->section_id);

         ret = se->ops->save_live_complete(f, se->opaque);
-        trace_savevm_section_end(se->section_id);
+        trace_savevm_section_end(se->idstr, se->section_id);
         if (ret < 0) {
             qemu_file_set_error(f, ret);
             return;
@@ -584,7 +584,7 @@ void qemu_savevm_state_complete(QEMUFile *f)
         if ((!se->ops || !se->ops->save_state) && !se->vmsd) {
             continue;
         }
-        trace_savevm_section_start();
+        trace_savevm_section_start(se->idstr, se->section_id);
         /* Section type */
         qemu_put_byte(f, QEMU_VM_SECTION_FULL);
         qemu_put_be32(f, se->section_id);
@@ -598,7 +598,7 @@ void qemu_savevm_state_complete(QEMUFile *f)
         qemu_put_be32(f, se->version_id);

         vmstate_save(f, se);
-        trace_savevm_section_end(se->section_id);
+        trace_savevm_section_end(se->idstr, se->section_id);
     }

     qemu_put_byte(f, QEMU_VM_EOF);
diff --git a/trace-events b/trace-events
index 466c27e..002c260 100644
--- a/trace-events
+++ b/trace-events
@@ -1040,8 +1040,8 @@ vmware_scratch_write(uint32_t index, uint32_t value) "index %d, value 0x%x"
 vmware_setmode(uint32_t w, uint32_t h, uint32_t bpp) "%dx%d @ %d bpp"

 # savevm.c
-savevm_section_start(void) ""
-savevm_section_end(unsigned int section_id) "section_id %u"
+savevm_section_start(const char *id, unsigned int section_id) "%s, section_id %u"
+savevm_section_end(const char *id, unsigned int section_id) "%s, section_id %u"

 # arch_init.c
 migration_bitmap_sync_start(void) ""
-- 
1.8.5.3

Re: [Qemu-devel] [PULL 0/4] migration queue

[Peter Maydell]

On 8 March 2014 21:32, Juan Quintela <quintela@redhat.com> wrote:
> The following changes since commit f53f3d0a00b6df39ce8dfca942608e5b6a9a4f71:
>
>   Merge remote-tracking branch 'remotes/kvaneesh/for-upstream' into staging (2014-03-08 12:38:43 +0000)
>
> are available in the git repository at:
>
>
>   git://github.com/juanquintela/qemu.git tags/migration/20140308-1
>
> for you to fetch changes up to 464400f6a5583eafb466595add435a3a33ea980f:
>
>   migration: extend section_start/end traces (2014-03-08 22:22:34 +0100)
>
> ----------------------------------------------------------------
> migration/next for 20140308

Applied, thanks.

-- PMM