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[PULL 27/30] migration/multifd: Report to user when zerocopy not working
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[PULL 27/30] migration/multifd: Report to user when zerocopy not working |
Date: |
Wed, 20 Jul 2022 12:19:23 +0100 |
From: Leonardo Bras <leobras@redhat.com>
Some errors, like the lack of Scatter-Gather support by the network
interface(NETIF_F_SG) may cause sendmsg(...,MSG_ZEROCOPY) to fail on using
zero-copy, which causes it to fall back to the default copying mechanism.
After each full dirty-bitmap scan there should be a zero-copy flush
happening, which checks for errors each of the previous calls to
sendmsg(...,MSG_ZEROCOPY). If all of them failed to use zero-copy, then
increment dirty_sync_missed_zero_copy migration stat to let the user know
about it.
Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220711211112.18951-4-leobras@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
migration/multifd.c | 2 ++
migration/ram.c | 5 +++++
migration/ram.h | 2 ++
3 files changed, 9 insertions(+)
diff --git a/migration/multifd.c b/migration/multifd.c
index 1e49594b02..586ddc9d65 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -624,6 +624,8 @@ int multifd_send_sync_main(QEMUFile *f)
if (ret < 0) {
error_report_err(err);
return -1;
+ } else if (ret == 1) {
+ dirty_sync_missed_zero_copy();
}
}
}
diff --git a/migration/ram.c b/migration/ram.c
index 4fbad74c6c..b94669ba5d 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -434,6 +434,11 @@ static void ram_transferred_add(uint64_t bytes)
ram_counters.transferred += bytes;
}
+void dirty_sync_missed_zero_copy(void)
+{
+ ram_counters.dirty_sync_missed_zero_copy++;
+}
+
/* used by the search for pages to send */
struct PageSearchStatus {
/* Current block being searched */
diff --git a/migration/ram.h b/migration/ram.h
index 5d90945a6e..c7af65ac74 100644
--- a/migration/ram.h
+++ b/migration/ram.h
@@ -89,4 +89,6 @@ void ram_write_tracking_prepare(void);
int ram_write_tracking_start(void);
void ram_write_tracking_stop(void);
+void dirty_sync_missed_zero_copy(void);
+
#endif
--
2.36.1
- [PULL 22/30] tests: Add postcopy tls recovery migration test, (continued)
- [PULL 22/30] tests: Add postcopy tls recovery migration test, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 18/30] migration: Enable TLS for preempt channel, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 09/30] multifd: Copy pages before compressing them with zlib, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 20/30] tests: Move MigrateCommon upper, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 24/30] migration: remove unreachable code after reading data, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 17/30] migration: Export tls-[creds|hostname|authz] params to cmdline too, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 26/30] Add dirty-sync-missed-zero-copy migration stat, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 21/30] tests: Add postcopy tls migration test, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 23/30] tests: Add postcopy preempt tests, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 30/30] Revert "gitlab: disable accelerated zlib for s390x", Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 27/30] migration/multifd: Report to user when zerocopy not working,
Dr. David Alan Gilbert (git) <=
- [PULL 28/30] multifd: Document the locking of MultiFD{Send/Recv}Params, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 25/30] QIOChannelSocket: Fix zero-copy flush returning code 1 when nothing sent, Dr. David Alan Gilbert (git), 2022/07/20
- [PULL 29/30] migration: Avoid false-positive on non-supported scenarios for zero-copy-send, Dr. David Alan Gilbert (git), 2022/07/20
- Re: [PULL 00/30] migration queue, Peter Maydell, 2022/07/21