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[Qemu-devel] [PATCH V6 09/17] COLO: Flush memory data from ram cache
From: |
Zhang Chen |
Subject: |
[Qemu-devel] [PATCH V6 09/17] COLO: Flush memory data from ram cache |
Date: |
Sun, 11 Mar 2018 15:45:06 +0800 |
From: zhanghailiang <address@hidden>
During the time of VM's running, PVM may dirty some pages, we will transfer
PVM's dirty pages to SVM and store them into SVM's RAM cache at next checkpoint
time. So, the content of SVM's RAM cache will always be same with PVM's memory
after checkpoint.
Instead of flushing all content of PVM's RAM cache into SVM's MEMORY,
we do this in a more efficient way:
Only flush any page that dirtied by PVM since last checkpoint.
In this way, we can ensure SVM's memory same with PVM's.
Besides, we must ensure flush RAM cache before load device state.
Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Li Zhijian <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
---
migration/ram.c | 39 +++++++++++++++++++++++++++++++++++++++
migration/trace-events | 2 ++
2 files changed, 41 insertions(+)
diff --git a/migration/ram.c b/migration/ram.c
index 4534c7a..ff7265e 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2927,6 +2927,40 @@ static bool postcopy_is_running(void)
return ps >= POSTCOPY_INCOMING_LISTENING && ps < POSTCOPY_INCOMING_END;
}
+/*
+ * Flush content of RAM cache into SVM's memory.
+ * Only flush the pages that be dirtied by PVM or SVM or both.
+ */
+static void colo_flush_ram_cache(void)
+{
+ RAMBlock *block = NULL;
+ void *dst_host;
+ void *src_host;
+ unsigned long offset = 0;
+
+ trace_colo_flush_ram_cache_begin(ram_state->migration_dirty_pages);
+ rcu_read_lock();
+ block = QLIST_FIRST_RCU(&ram_list.blocks);
+
+ while (block) {
+ offset = migration_bitmap_find_dirty(ram_state, block, offset);
+ migration_bitmap_clear_dirty(ram_state, block, offset);
+
+ if (offset << TARGET_PAGE_BITS >= block->used_length) {
+ offset = 0;
+ block = QLIST_NEXT_RCU(block, next);
+ } else {
+ dst_host = block->host + (offset << TARGET_PAGE_BITS);
+ src_host = block->colo_cache + (offset << TARGET_PAGE_BITS);
+ memcpy(dst_host, src_host, TARGET_PAGE_SIZE);
+ }
+ }
+
+ rcu_read_unlock();
+ trace_colo_flush_ram_cache_end();
+ assert(ram_state->migration_dirty_pages == 0);
+}
+
static int ram_load(QEMUFile *f, void *opaque, int version_id)
{
int flags = 0, ret = 0, invalid_flags = 0;
@@ -2939,6 +2973,7 @@ static int ram_load(QEMUFile *f, void *opaque, int
version_id)
bool postcopy_running = postcopy_is_running();
/* ADVISE is earlier, it shows the source has the postcopy capability on */
bool postcopy_advised = postcopy_is_advised();
+ bool need_flush = false;
seq_iter++;
@@ -3114,6 +3149,10 @@ static int ram_load(QEMUFile *f, void *opaque, int
version_id)
wait_for_decompress_done();
rcu_read_unlock();
trace_ram_load_complete(ret, seq_iter);
+
+ if (!ret && migration_incoming_in_colo_state() && need_flush) {
+ colo_flush_ram_cache();
+ }
return ret;
}
diff --git a/migration/trace-events b/migration/trace-events
index b27a3a0..a3a124b 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -78,6 +78,8 @@ ram_load_postcopy_loop(uint64_t addr, int flags) "@%" PRIx64
" %x"
ram_postcopy_send_discard_bitmap(void) ""
ram_save_page(const char *rbname, uint64_t offset, void *host) "%s: offset:
0x%" PRIx64 " host: %p"
ram_save_queue_pages(const char *rbname, size_t start, size_t len) "%s: start:
0x%zx len: 0x%zx"
+colo_flush_ram_cache_begin(uint64_t dirty_pages) "dirty_pages %" PRIu64
+colo_flush_ram_cache_end(void) ""
# migration/migration.c
await_return_path_close_on_source_close(void) ""
--
2.7.4
- [Qemu-devel] [PATCH V6 00/17] COLO: integrate colo frame with block replication and COLO proxy, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 00/17] COLO: integrate colo frame with block replication and COLO proxy, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 01/17] filter-rewriter: fix memory leak for connection in connection_track_table, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 02/17] colo-compare: implement the process of checkpoint, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 03/17] colo-compare: use notifier to notify packets comparing result, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 04/17] COLO: integrate colo compare with colo frame, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 05/17] COLO: Add block replication into colo process, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 06/17] COLO: Remove colo_state migration struct, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 07/17] COLO: Load dirty pages into SVM's RAM cache firstly, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 08/17] ram/COLO: Record the dirty pages that SVM received, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 09/17] COLO: Flush memory data from ram cache,
Zhang Chen <=
- [Qemu-devel] [PATCH V6 10/17] qmp event: Add COLO_EXIT event to notify users while exited COLO, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 11/17] qapi: Add new command to query colo status, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 12/17] savevm: split the process of different stages for loadvm/savevm, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 13/17] COLO: flush host dirty ram from cache, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 14/17] filter: Add handle_event method for NetFilterClass, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 15/17] filter-rewriter: handle checkpoint and failover event, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 16/17] COLO: notify net filters about checkpoint/failover event, Zhang Chen, 2018/03/11
- [Qemu-devel] [PATCH V6 17/17] COLO: quick failover process by kick COLO thread, Zhang Chen, 2018/03/11