From 3b57c876e1eaca34fb5bd9067553de945013d4be Mon Sep 17 00:00:00 2001

From: Juan Quintela <quintela@redhat.com>

Date: Wed, 18 May 2022 02:52:24 -0300

Subject: [PATCH 16/37] multifd: Use normal pages array on the send side

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RH-Author: Leonardo Brás <leobras@redhat.com>

RH-MergeRequest: 191: MSG_ZEROCOPY + Multifd @ rhel8.7

RH-Commit: [16/26] 1c48806474daf48fe93920ac361311af95c6a6f3

RH-Bugzilla: 2072049

RH-Acked-by: Peter Xu <peterx@redhat.com>

RH-Acked-by: Daniel P. Berrangé <berrange@redhat.com>

RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

We are only sending normal pages through multifd channels.

Later on this series, we are going to also send zero pages.

We are going to detect if a page is zero or non zero in the multifd

channel thread, not on the main thread.

So we receive an array of pages page->offset[N]

And we will end with:

p->normal[N - zero_pages]

p->zero[zero_pages].

In this patch, we just copy all the pages in offset to normal.

for (i = 0; i < pages->num; i++) {

    p->narmal[p->normal_num] = pages->offset[i];

    p->normal_num++:

}

Later in the series this becomes:

for (i = 0; i < pages->num; i++) {

    if (buffer_is_zero(page->offset[i])) {

        p->zerol[p->zero_num] = pages->offset[i];

        p->zero_num++:

    } else {

        p->narmal[p->normal_num] = pages->offset[i];

        p->normal_num++:

    }

}

Signed-off-by: Juan Quintela <quintela@redhat.com>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

---

Improving comment (dave)

Renaming num_normal_pages to total_normal_pages (peter)

(cherry picked from commit 815956f03902980c771da64b17f7f791c1cb57b0)

Signed-off-by: Leonardo Bras <leobras@redhat.com>

---

 migration/multifd-zlib.c |  6 +++---

 migration/multifd-zstd.c |  6 +++---

 migration/multifd.c      | 30 +++++++++++++++++++-----------

 migration/multifd.h      |  8 ++++++--

 migration/trace-events   |  4 ++--

 5 files changed, 33 insertions(+), 21 deletions(-)

diff --git a/migration/multifd-zlib.c b/migration/multifd-zlib.c

index 8ed29b9633..8508f26adf 100644

--- a/migration/multifd-zlib.c

+++ b/migration/multifd-zlib.c

@@ -108,16 +108,16 @@ static int zlib_send_prepare(MultiFDSendParams *p, Error **errp)

     int ret;

     uint32_t i;

-    for (i = 0; i < p->pages->num; i++) {

+    for (i = 0; i < p->normal_num; i++) {

         uint32_t available = z->zbuff_len - out_size;

         int flush = Z_NO_FLUSH;

-        if (i == p->pages->num - 1) {

+        if (i == p->normal_num - 1) {

             flush = Z_SYNC_FLUSH;

         }

         zs->avail_in = page_size;

-        zs->next_in = p->pages->block->host + p->pages->offset[i];

+        zs->next_in = p->pages->block->host + p->normal[i];

         zs->avail_out = available;

         zs->next_out = z->zbuff + out_size;

diff --git a/migration/multifd-zstd.c b/migration/multifd-zstd.c

index 25e1f517b5..693af3a140 100644

--- a/migration/multifd-zstd.c

+++ b/migration/multifd-zstd.c

@@ -123,13 +123,13 @@ static int zstd_send_prepare(MultiFDSendParams *p, Error **errp)

     z->out.size = z->zbuff_len;

     z->out.pos = 0;

-    for (i = 0; i < p->pages->num; i++) {

+    for (i = 0; i < p->normal_num; i++) {

         ZSTD_EndDirective flush = ZSTD_e_continue;

-        if (i == p->pages->num - 1) {

+        if (i == p->normal_num - 1) {

             flush = ZSTD_e_flush;

         }

-        z->in.src = p->pages->block->host + p->pages->offset[i];

+        z->in.src = p->pages->block->host + p->normal[i];

         z->in.size = page_size;

         z->in.pos = 0;

diff --git a/migration/multifd.c b/migration/multifd.c

index d0f86542b1..3725226400 100644

--- a/migration/multifd.c

+++ b/migration/multifd.c

@@ -89,13 +89,13 @@ static int nocomp_send_prepare(MultiFDSendParams *p, Error **errp)

     MultiFDPages_t *pages = p->pages;

     size_t page_size = qemu_target_page_size();

-    for (int i = 0; i < p->pages->num; i++) {

-        p->iov[p->iovs_num].iov_base = pages->block->host + pages->offset[i];

+    for (int i = 0; i < p->normal_num; i++) {

+        p->iov[p->iovs_num].iov_base = pages->block->host + p->normal[i];

         p->iov[p->iovs_num].iov_len = page_size;

         p->iovs_num++;

     }

-    p->next_packet_size = p->pages->num * page_size;

+    p->next_packet_size = p->normal_num * page_size;

     p->flags |= MULTIFD_FLAG_NOCOMP;

     return 0;

 }

@@ -262,7 +262,7 @@ static void multifd_send_fill_packet(MultiFDSendParams *p)

     packet->flags = cpu_to_be32(p->flags);

     packet->pages_alloc = cpu_to_be32(p->pages->allocated);

-    packet->pages_used = cpu_to_be32(p->pages->num);

+    packet->pages_used = cpu_to_be32(p->normal_num);

     packet->next_packet_size = cpu_to_be32(p->next_packet_size);

     packet->packet_num = cpu_to_be64(p->packet_num);

@@ -270,9 +270,9 @@ static void multifd_send_fill_packet(MultiFDSendParams *p)

         strncpy(packet->ramblock, p->pages->block->idstr, 256);

     }

-    for (i = 0; i < p->pages->num; i++) {

+    for (i = 0; i < p->normal_num; i++) {

         /* there are architectures where ram_addr_t is 32 bit */

-        uint64_t temp = p->pages->offset[i];

+        uint64_t temp = p->normal[i];

         packet->offset[i] = cpu_to_be64(temp);

     }

@@ -556,6 +556,8 @@ void multifd_save_cleanup(void)

         p->packet = NULL;

         g_free(p->iov);

         p->iov = NULL;

+        g_free(p->normal);

+        p->normal = NULL;

         multifd_send_state->ops->send_cleanup(p, &local_err);

         if (local_err) {

             migrate_set_error(migrate_get_current(), local_err);

@@ -640,12 +642,17 @@ static void *multifd_send_thread(void *opaque)

         qemu_mutex_lock(&p->mutex);

         if (p->pending_job) {

-            uint32_t used = p->pages->num;

             uint64_t packet_num = p->packet_num;

             uint32_t flags = p->flags;

             p->iovs_num = 1;

+            p->normal_num = 0;

+

+            for (int i = 0; i < p->pages->num; i++) {

+                p->normal[p->normal_num] = p->pages->offset[i];

+                p->normal_num++;

+            }

-            if (used) {

+            if (p->normal_num) {

                 ret = multifd_send_state->ops->send_prepare(p, &local_err);

                 if (ret != 0) {

                     qemu_mutex_unlock(&p->mutex);

@@ -655,12 +662,12 @@ static void *multifd_send_thread(void *opaque)

             multifd_send_fill_packet(p);

             p->flags = 0;

             p->num_packets++;

-            p->num_pages += used;

+            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, used, flags,

+            trace_multifd_send(p->id, packet_num, p->normal_num, flags,

                                p->next_packet_size);

             p->iov[0].iov_len = p->packet_len;

@@ -710,7 +717,7 @@ out:

     qemu_mutex_unlock(&p->mutex);

     rcu_unregister_thread();

-    trace_multifd_send_thread_end(p->id, p->num_packets, p->num_pages);

+    trace_multifd_send_thread_end(p->id, p->num_packets, p->total_normal_pages);

     return NULL;

 }

@@ -910,6 +917,7 @@ int multifd_save_setup(Error **errp)

         p->tls_hostname = g_strdup(s->hostname);

         /* We need one extra place for the packet header */

         p->iov = g_new0(struct iovec, page_count + 1);

+        p->normal = g_new0(ram_addr_t, page_count);

         socket_send_channel_create(multifd_new_send_channel_async, p);

     }

diff --git a/migration/multifd.h b/migration/multifd.h

index 7496f951a7..7823199dbe 100644

--- a/migration/multifd.h

+++ b/migration/multifd.h

@@ -104,14 +104,18 @@ typedef struct {

     /* thread local variables */

     /* packets sent through this channel */

     uint64_t num_packets;

-    /* pages sent through this channel */

-    uint64_t num_pages;

+    /* non zero pages sent through this channel */

+    uint64_t total_normal_pages;

     /* syncs main thread and channels */

     QemuSemaphore sem_sync;

     /* buffers to send */

     struct iovec *iov;

     /* number of iovs used */

     uint32_t iovs_num;

+    /* Pages that are not zero */

+    ram_addr_t *normal;

+    /* num of non zero pages */

+    uint32_t normal_num;

     /* used for compression methods */

     void *data;

 }  MultiFDSendParams;

diff --git a/migration/trace-events b/migration/trace-events

index 5172cb3b3d..171a83a55d 100644

--- a/migration/trace-events

+++ b/migration/trace-events

@@ -124,13 +124,13 @@ multifd_recv_sync_main_wait(uint8_t id) "channel %u"

 multifd_recv_terminate_threads(bool error) "error %d"

 multifd_recv_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %u packets %" PRIu64 " pages %" PRIu64

 multifd_recv_thread_start(uint8_t id) "%u"

-multifd_send(uint8_t id, uint64_t packet_num, uint32_t used, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " pages %u flags 0x%x next packet size %u"

+multifd_send(uint8_t id, uint64_t packet_num, uint32_t normal, uint32_t flags, uint32_t next_packet_size) "channel %u packet_num %" PRIu64 " normal pages %u flags 0x%x next packet size %u"

 multifd_send_error(uint8_t id) "channel %u"

 multifd_send_sync_main(long packet_num) "packet num %ld"

 multifd_send_sync_main_signal(uint8_t id) "channel %u"

 multifd_send_sync_main_wait(uint8_t id) "channel %u"

 multifd_send_terminate_threads(bool error) "error %d"

-multifd_send_thread_end(uint8_t id, uint64_t packets, uint64_t pages) "channel %u packets %" PRIu64 " pages %"  PRIu64

+multifd_send_thread_end(uint8_t id, uint64_t packets, uint64_t normal_pages) "channel %u packets %" PRIu64 " normal pages %"  PRIu64

 multifd_send_thread_start(uint8_t id) "%u"

 multifd_tls_outgoing_handshake_start(void *ioc, void *tioc, const char *hostname) "ioc=%p tioc=%p hostname=%s"

 multifd_tls_outgoing_handshake_error(void *ioc, const char *err) "ioc=%p err=%s"

-- 

2.35.3