| Message ID | 20220531104318.7494-9-quintela@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | Migration: Transmit and detect zero pages in the multifd threads | expand |
* Juan Quintela (quintela@redhat.com) wrote: > We do the send_prepare() and the fill of the head packet without the > mutex held. It will help a lot for compression and later in the > series for zero pages. > > Notice that we can use p->pages without holding p->mutex because > p->pending_job == 1. > > Signed-off-by: Juan Quintela <quintela@redhat.com> > --- > migration/multifd.h | 2 ++ > migration/multifd.c | 11 ++++++----- > 2 files changed, 8 insertions(+), 5 deletions(-) > > diff --git a/migration/multifd.h b/migration/multifd.h > index af8ce8921d..d48597a1ea 100644 > --- a/migration/multifd.h > +++ b/migration/multifd.h > @@ -109,7 +109,9 @@ typedef struct { > /* array of pages to sent. > * The owner of 'pages' depends of 'pending_job' value: > * pending_job == 0 -> migration_thread can use it. > + * No need for mutex lock. > * pending_job != 0 -> multifd_channel can use it. > + * No need for mutex lock. > */ > MultiFDPages_t *pages; > > diff --git a/migration/multifd.c b/migration/multifd.c > index 69b9d7cf98..056599cbaf 100644 > --- a/migration/multifd.c > +++ b/migration/multifd.c > @@ -661,6 +661,8 @@ static void *multifd_send_thread(void *opaque) > p->flags |= MULTIFD_FLAG_SYNC; > p->sync_needed = false; > } > + qemu_mutex_unlock(&p->mutex); > + > p->normal_num = 0; > > if (use_zero_copy_send) { > @@ -682,11 +684,6 @@ static void *multifd_send_thread(void *opaque) Looking at my source tree, without the rest of your series, I see an unlock just before this pair of }'s; doesn't that need to go? Dave > } > } > multifd_send_fill_packet(p); > - p->num_packets++; > - p->total_normal_pages += p->normal_num; > - p->pages->num = 0; > - p->pages->block = NULL; > - qemu_mutex_unlock(&p->mutex); > > trace_multifd_send(p->id, packet_num, p->normal_num, p->flags, > p->next_packet_size); > @@ -711,6 +708,10 @@ static void *multifd_send_thread(void *opaque) > } > > qemu_mutex_lock(&p->mutex); > + p->num_packets++; > + p->total_normal_pages += p->normal_num; > + p->pages->num = 0; > + p->pages->block = NULL; > p->sent_bytes += p->packet_len;; > p->sent_bytes += p->next_packet_size; > p->pending_job--; > -- > 2.35.3 >
diff --git a/migration/multifd.h b/migration/multifd.h index af8ce8921d..d48597a1ea 100644 --- a/migration/multifd.h +++ b/migration/multifd.h @@ -109,7 +109,9 @@ typedef struct { /* array of pages to sent. * The owner of 'pages' depends of 'pending_job' value: * pending_job == 0 -> migration_thread can use it. + * No need for mutex lock. * pending_job != 0 -> multifd_channel can use it. + * No need for mutex lock. */ MultiFDPages_t *pages; diff --git a/migration/multifd.c b/migration/multifd.c index 69b9d7cf98..056599cbaf 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -661,6 +661,8 @@ static void *multifd_send_thread(void *opaque) p->flags |= MULTIFD_FLAG_SYNC; p->sync_needed = false; } + qemu_mutex_unlock(&p->mutex); + p->normal_num = 0; if (use_zero_copy_send) { @@ -682,11 +684,6 @@ static void *multifd_send_thread(void *opaque) } } multifd_send_fill_packet(p); - p->num_packets++; - p->total_normal_pages += p->normal_num; - p->pages->num = 0; - p->pages->block = NULL; - qemu_mutex_unlock(&p->mutex); trace_multifd_send(p->id, packet_num, p->normal_num, p->flags, p->next_packet_size); @@ -711,6 +708,10 @@ static void *multifd_send_thread(void *opaque) } qemu_mutex_lock(&p->mutex); + p->num_packets++; + p->total_normal_pages += p->normal_num; + p->pages->num = 0; + p->pages->block = NULL; p->sent_bytes += p->packet_len;; p->sent_bytes += p->next_packet_size; p->pending_job--;
We do the send_prepare() and the fill of the head packet without the mutex held. It will help a lot for compression and later in the series for zero pages. Notice that we can use p->pages without holding p->mutex because p->pending_job == 1. Signed-off-by: Juan Quintela <quintela@redhat.com> --- migration/multifd.h | 2 ++ migration/multifd.c | 11 ++++++----- 2 files changed, 8 insertions(+), 5 deletions(-)