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[Qemu-devel] [PATCH V7 RESEND 09/17] COLO: Flush memory data from ram ca
From: |
Zhang Chen |
Subject: |
[Qemu-devel] [PATCH V7 RESEND 09/17] COLO: Flush memory data from ram cache |
Date: |
Tue, 15 May 2018 00:54:16 +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 e35dfee06e..4235a8f24d 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 9295b4cf40..8e2f9749e0 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) ""
--
2.17.0
- Re: [Qemu-devel] [PATCH V7 RESEND 04/17] COLO: integrate colo compare with colo frame, (continued)
- [Qemu-devel] [PATCH V7 RESEND 05/17] COLO: Add block replication into colo process, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 06/17] COLO: Remove colo_state migration struct, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 07/17] COLO: Load dirty pages into SVM's RAM cache firstly, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 08/17] ram/COLO: Record the dirty pages that SVM received, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 09/17] COLO: Flush memory data from ram cache,
Zhang Chen <=
- [Qemu-devel] [PATCH V7 RESEND 10/17] qmp event: Add COLO_EXIT event to notify users while exited COLO, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 11/17] qapi: Add new command to query colo status, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 12/17] savevm: split the process of different stages for loadvm/savevm, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 13/17] COLO: flush host dirty ram from cache, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 14/17] filter: Add handle_event method for NetFilterClass, Zhang Chen, 2018/05/14
- [Qemu-devel] [PATCH V7 RESEND 16/17] COLO: notify net filters about checkpoint/failover event, Zhang Chen, 2018/05/14