From: Juan Quintela <quintela@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
"Dr. David Alan Gilbert" <dgilbert@redhat.com>,
"Leonardo Bras" <leobras@redhat.com>,
"Peter Xu" <peterx@redhat.com>, "Eric Blake" <eblake@redhat.com>,
"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
"Yanan Wang" <wangyanan55@huawei.com>,
"Juan Quintela" <quintela@redhat.com>,
"Markus Armbruster" <armbru@redhat.com>,
"Eduardo Habkost" <eduardo@habkost.net>
Subject: [PATCH v7 06/12] multifd: Make flags field thread local
Date: Tue, 2 Aug 2022 08:39:01 +0200 [thread overview]
Message-ID: <20220802063907.18882-7-quintela@redhat.com> (raw)
In-Reply-To: <20220802063907.18882-1-quintela@redhat.com>
Use of flags with respect to locking was incensistant. For the
sending side:
- it was set to 0 with mutex held on the multifd channel.
- MULTIFD_FLAG_SYNC was set with mutex held on the migration thread.
- Everything else was done without the mutex held on the multifd channel.
On the reception side, it is not used on the migration thread, only on
the multifd channels threads.
So we move it to the multifd channels thread only variables, and we
introduce a new bool sync_needed on the send side to pass that information.
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
migration/multifd.h | 10 ++++++----
migration/multifd.c | 23 +++++++++++++----------
2 files changed, 19 insertions(+), 14 deletions(-)
diff --git a/migration/multifd.h b/migration/multifd.h
index 36f899c56f..a67cefc0a2 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -98,12 +98,12 @@ typedef struct {
bool running;
/* should this thread finish */
bool quit;
- /* multifd flags for each packet */
- uint32_t flags;
/* global number of generated multifd packets */
uint64_t packet_num;
/* How many bytes have we sent on the last packet */
uint64_t sent_bytes;
+ /* Do we need to do an iteration sync */
+ bool sync_needed;
/* thread has work to do */
int pending_job;
/* array of pages to sent.
@@ -117,6 +117,8 @@ typedef struct {
/* pointer to the packet */
MultiFDPacket_t *packet;
+ /* multifd flags for each packet */
+ uint32_t flags;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
/* packets sent through this channel */
@@ -163,8 +165,6 @@ typedef struct {
bool running;
/* should this thread finish */
bool quit;
- /* multifd flags for each packet */
- uint32_t flags;
/* global number of generated multifd packets */
uint64_t packet_num;
@@ -172,6 +172,8 @@ typedef struct {
/* pointer to the packet */
MultiFDPacket_t *packet;
+ /* multifd flags for each packet */
+ uint32_t flags;
/* size of the next packet that contains pages */
uint32_t next_packet_size;
/* packets sent through this channel */
diff --git a/migration/multifd.c b/migration/multifd.c
index e25b529235..09a40a9135 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -602,7 +602,7 @@ int multifd_send_sync_main(QEMUFile *f)
}
p->packet_num = multifd_send_state->packet_num++;
- p->flags |= MULTIFD_FLAG_SYNC;
+ p->sync_needed = true;
p->pending_job++;
qemu_mutex_unlock(&p->mutex);
qemu_sem_post(&p->sem);
@@ -658,7 +658,11 @@ static void *multifd_send_thread(void *opaque)
if (p->pending_job) {
uint64_t packet_num = p->packet_num;
- uint32_t flags = p->flags;
+ p->flags = 0;
+ if (p->sync_needed) {
+ p->flags |= MULTIFD_FLAG_SYNC;
+ p->sync_needed = false;
+ }
p->normal_num = 0;
if (use_zero_copy_send) {
@@ -680,14 +684,13 @@ static void *multifd_send_thread(void *opaque)
}
}
multifd_send_fill_packet(p);
- p->flags = 0;
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, flags,
+ trace_multifd_send(p->id, packet_num, p->normal_num, p->flags,
p->next_packet_size);
if (use_zero_copy_send) {
@@ -715,7 +718,7 @@ static void *multifd_send_thread(void *opaque)
p->pending_job--;
qemu_mutex_unlock(&p->mutex);
- if (flags & MULTIFD_FLAG_SYNC) {
+ if (p->flags & MULTIFD_FLAG_SYNC) {
qemu_sem_post(&p->sem_sync);
}
qemu_sem_post(&multifd_send_state->channels_ready);
@@ -1090,7 +1093,7 @@ static void *multifd_recv_thread(void *opaque)
rcu_register_thread();
while (true) {
- uint32_t flags;
+ bool sync_needed = false;
if (p->quit) {
break;
@@ -1112,11 +1115,11 @@ static void *multifd_recv_thread(void *opaque)
break;
}
- flags = p->flags;
+ trace_multifd_recv(p->id, p->packet_num, p->normal_num, p->flags,
+ p->next_packet_size);
+ sync_needed = p->flags & MULTIFD_FLAG_SYNC;
/* recv methods don't know how to handle the SYNC flag */
p->flags &= ~MULTIFD_FLAG_SYNC;
- trace_multifd_recv(p->id, p->packet_num, p->normal_num, flags,
- p->next_packet_size);
p->num_packets++;
p->total_normal_pages += p->normal_num;
qemu_mutex_unlock(&p->mutex);
@@ -1128,7 +1131,7 @@ static void *multifd_recv_thread(void *opaque)
}
}
- if (flags & MULTIFD_FLAG_SYNC) {
+ if (sync_needed) {
qemu_sem_post(&multifd_recv_state->sem_sync);
qemu_sem_wait(&p->sem_sync);
}
--
2.37.1
next prev parent reply other threads:[~2022-08-02 6:49 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-02 6:38 [PATCH v7 00/12] Migration: Transmit and detect zero pages in the multifd threads Juan Quintela
2022-08-02 6:38 ` [PATCH v7 01/12] multifd: Create page_size fields into both MultiFD{Recv, Send}Params Juan Quintela
2022-08-11 8:10 ` [PATCH v7 01/12] multifd: Create page_size fields into both MultiFD{Recv,Send}Params Leonardo Brás
2022-08-13 15:41 ` Juan Quintela
2022-08-02 6:38 ` [PATCH v7 02/12] multifd: Create page_count fields into both MultiFD{Recv, Send}Params Juan Quintela
2022-08-11 8:10 ` [PATCH v7 02/12] multifd: Create page_count fields into both MultiFD{Recv,Send}Params Leonardo Brás
2022-08-02 6:38 ` [PATCH v7 03/12] migration: Export ram_transferred_ram() Juan Quintela
2022-08-11 8:11 ` Leonardo Brás
2022-08-13 15:36 ` Juan Quintela
2022-08-02 6:38 ` [PATCH v7 04/12] multifd: Count the number of bytes sent correctly Juan Quintela
2022-08-11 8:11 ` Leonardo Brás
2022-08-19 9:35 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 05/12] migration: Make ram_save_target_page() a pointer Juan Quintela
2022-08-11 8:11 ` Leonardo Brás
2022-08-19 9:51 ` Juan Quintela
2022-08-20 7:14 ` Leonardo Bras Soares Passos
2022-08-22 21:35 ` Juan Quintela
2022-08-02 6:39 ` Juan Quintela [this message]
2022-08-11 9:04 ` [PATCH v7 06/12] multifd: Make flags field thread local Leonardo Brás
2022-08-19 10:03 ` Juan Quintela
2022-08-20 7:24 ` Leonardo Bras Soares Passos
2022-08-23 13:00 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 07/12] multifd: Prepare to send a packet without the mutex held Juan Quintela
2022-08-11 9:16 ` Leonardo Brás
2022-08-19 11:32 ` Juan Quintela
2022-08-20 7:27 ` Leonardo Bras Soares Passos
2022-08-02 6:39 ` [PATCH v7 08/12] multifd: Add capability to enable/disable zero_page Juan Quintela
2022-08-11 9:29 ` Leonardo Brás
2022-08-19 11:36 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 09/12] migration: Export ram_release_page() Juan Quintela
2022-08-11 9:31 ` Leonardo Brás
2022-08-02 6:39 ` [PATCH v7 10/12] multifd: Support for zero pages transmission Juan Quintela
2022-09-02 13:27 ` Leonardo Brás
2022-11-14 12:09 ` Juan Quintela
2022-10-25 9:10 ` chuang xu
2022-11-14 12:10 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 11/12] multifd: Zero " Juan Quintela
2022-09-02 13:27 ` Leonardo Brás
2022-11-14 12:20 ` Juan Quintela
2022-11-14 12:27 ` Juan Quintela
2022-08-02 6:39 ` [PATCH v7 12/12] So we use multifd to transmit zero pages Juan Quintela
2022-09-02 13:27 ` Leonardo Brás
2022-11-14 12:30 ` Juan Quintela
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