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[PATCH v3 22/23] multifd: Zero pages transmission
From: |
Juan Quintela |
Subject: |
[PATCH v3 22/23] multifd: Zero pages transmission |
Date: |
Wed, 24 Nov 2021 11:06:16 +0100 |
This implements the zero page dection and handling.
Signed-off-by: Juan Quintela <quintela@redhat.com>
---
migration/multifd.c | 33 +++++++++++++++++++++++++++++++--
1 file changed, 31 insertions(+), 2 deletions(-)
diff --git a/migration/multifd.c b/migration/multifd.c
index 2e4dffd6c6..5c1fc70ce3 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -11,6 +11,7 @@
*/
#include "qemu/osdep.h"
+#include "qemu/cutils.h"
#include "qemu/rcu.h"
#include "exec/target_page.h"
#include "sysemu/sysemu.h"
@@ -277,6 +278,12 @@ static void multifd_send_fill_packet(MultiFDSendParams *p)
packet->offset[i] = cpu_to_be64(temp);
}
+ for (i = 0; i < p->zero_num; i++) {
+ /* there are architectures where ram_addr_t is 32 bit */
+ uint64_t temp = p->zero[i];
+
+ packet->offset[p->normal_num + i] = cpu_to_be64(temp);
+ }
}
static int multifd_recv_unfill_packet(MultiFDRecvParams *p, Error **errp)
@@ -362,6 +369,18 @@ static int multifd_recv_unfill_packet(MultiFDRecvParams
*p, Error **errp)
p->normal[i] = offset;
}
+ for (i = 0; i < p->zero_num; i++) {
+ uint64_t offset = be64_to_cpu(packet->offset[p->normal_num + i]);
+
+ if (offset > (block->used_length - page_size)) {
+ error_setg(errp, "multifd: offset too long %" PRIu64
+ " (max " RAM_ADDR_FMT ")",
+ offset, block->used_length);
+ return -1;
+ }
+ p->zero[i] = offset;
+ }
+
return 0;
}
@@ -652,8 +671,14 @@ static void *multifd_send_thread(void *opaque)
p->zero_num = 0;
for (int i = 0; i < p->pages->num; i++) {
- p->normal[p->normal_num] = p->pages->offset[i];
- p->normal_num++;
+ if (buffer_is_zero(p->pages->block->host + p->pages->offset[i],
+ qemu_target_page_size())) {
+ p->zero[p->zero_num] = p->pages->offset[i];
+ p->zero_num++;
+ } else {
+ p->normal[p->normal_num] = p->pages->offset[i];
+ p->normal_num++;
+ }
}
if (p->normal_num) {
@@ -1112,6 +1137,10 @@ static void *multifd_recv_thread(void *opaque)
}
}
+ for (int i = 0; i < p->zero_num; i++) {
+ memset(p->host + p->zero[i], 0, qemu_target_page_size());
+ }
+
if (flags & MULTIFD_FLAG_SYNC) {
qemu_sem_post(&multifd_recv_state->sem_sync);
qemu_sem_wait(&p->sem_sync);
--
2.33.1
- [PATCH v3 06/23] multifd: remove used parameter from send_prepare() method, (continued)
- [PATCH v3 06/23] multifd: remove used parameter from send_prepare() method, Juan Quintela, 2021/11/24
- [PATCH v3 13/23] multifd: Make zstd use iov's, Juan Quintela, 2021/11/24
- [PATCH v3 15/23] multifd: Use a single writev on the send side, Juan Quintela, 2021/11/24
- [PATCH v3 16/23] multifd: Unfold "used" variable by its value, Juan Quintela, 2021/11/24
- [PATCH v3 17/23] multifd: Use normal pages array on the send side, Juan Quintela, 2021/11/24
- [PATCH v3 14/23] multifd: Remove send_write() method, Juan Quintela, 2021/11/24
- [PATCH v3 18/23] multifd: Use normal pages array on the recv side, Juan Quintela, 2021/11/24
- [PATCH v3 19/23] multifd: recv side only needs the RAMBlock host address, Juan Quintela, 2021/11/24
- [PATCH v3 20/23] multifd: Rename pages_used to normal_pages, Juan Quintela, 2021/11/24
- [PATCH v3 21/23] multifd: Support for zero pages transmission, Juan Quintela, 2021/11/24
- [PATCH v3 22/23] multifd: Zero pages transmission,
Juan Quintela <=
- [PATCH v3 23/23] migration: Use multifd before we check for the zero page, Juan Quintela, 2021/11/24
- Re: [PATCH v3 00/23] Migration: Transmit and detect zero pages in the multifd threads, Peter Xu, 2021/11/24