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[Qemu-devel] [PATCH V7 09/17] COLO: Flush memory data from ram cache
From: |
Zhang Chen |
Subject: |
[Qemu-devel] [PATCH V7 09/17] COLO: Flush memory data from ram cache |
Date: |
Mon, 14 May 2018 11:23:40 +0800 |
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 e35dfee..4235a8f 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3031,6 +3031,40 @@ 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;
@@ -3043,6 +3077,7 @@ 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++;
@@ -3218,6 +3253,10 @@ static int ram_load(QEMUFile *f, void *opaque, int
version_id)
ret |= 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 9295b4c..8e2f974 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 V7 00/17] COLO: integrate colo frame with block replication and COLO proxy, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 06/17] COLO: Remove colo_state migration struct, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 05/17] COLO: Add block replication into colo process, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 13/17] COLO: flush host dirty ram from cache, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 01/17] filter-rewriter: fix memory leak for connection in connection_track_table, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 09/17] COLO: Flush memory data from ram cache,
Zhang Chen <=
- [Qemu-devel] [PATCH V7 03/17] colo-compare: use notifier to notify packets comparing result, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 07/17] COLO: Load dirty pages into SVM's RAM cache firstly, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 02/17] colo-compare: implement the process of checkpoint, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 14/17] filter: Add handle_event method for NetFilterClass, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 11/17] qapi: Add new command to query colo status, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 15/17] filter-rewriter: handle checkpoint and failover event, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 08/17] ram/COLO: Record the dirty pages that SVM received, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 10/17] qmp event: Add COLO_EXIT event to notify users while exited COLO, Zhang Chen, 2018/05/14