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authorLeonardo Bras <leobras@redhat.com>2022-07-11 18:11:13 -0300
committerDr. David Alan Gilbert <dgilbert@redhat.com>2022-07-20 12:15:09 +0100
commitd59c40cc483729f2e67c80e58df769ad19976fe9 (patch)
tree252bf54ccd0ff3a7f405dd8691a98dcbad79e595 /migration
parentcf20c897338067ab4b70a4596fdccaf90c7e29a1 (diff)
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migration/multifd: Report to user when zerocopy not working
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>
Diffstat (limited to 'migration')
-rw-r--r--migration/multifd.c2
-rw-r--r--migration/ram.c5
-rw-r--r--migration/ram.h2
3 files changed, 9 insertions, 0 deletions
diff --git a/migration/multifd.c b/migration/multifd.c
index 1e49594..586ddc9 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 4fbad74..b94669b 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 5d90945..c7af65a 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