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From: Peter Xu <peterx@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Li Zhijian" <lizhijian@fujitsu.com>,
	"Hailiang Zhang" <zhanghailiang@xfusion.com>,
	"Kevin Wolf" <kwolf@redhat.com>,
	"Vladimir Sementsov-Ogievskiy" <vsementsov@yandex-team.ru>,
	peterx@redhat.com, "Daniel P . Berrangé" <berrange@redhat.com>,
	"Fabiano Rosas" <farosas@suse.de>,
	"Zhang Chen" <zhangckid@gmail.com>,
	"Dr . David Alan Gilbert" <dave@treblig.org>,
	"Prasad Pandit" <ppandit@redhat.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Yury Kotov" <yury-kotov@yandex-team.ru>,
	"Juraj Marcin" <jmarcin@redhat.com>
Subject: [PATCH 11/13] migration/ram: Remove workaround on ram yield during load
Date: Wed, 22 Oct 2025 15:26:10 -0400	[thread overview]
Message-ID: <20251022192612.2737648-12-peterx@redhat.com> (raw)
In-Reply-To: <20251022192612.2737648-1-peterx@redhat.com>

This reverts e65cec5e5d97927d22b39167d3e8edeffc771788.

RAM load path had a hack in the past explicitly yield the thread to the
main coroutine when RAM load spinning in a tight loop.  Not needed now
because precopy RAM load now happens without the main thread.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/ram.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 29f016cb25..16e81cf3bb 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -4304,7 +4304,7 @@ static int parse_ramblocks(QEMUFile *f, ram_addr_t total_ram_bytes)
 static int ram_load_precopy(QEMUFile *f)
 {
     MigrationIncomingState *mis = migration_incoming_get_current();
-    int flags = 0, ret = 0, invalid_flags = 0, i = 0;
+    int flags = 0, ret = 0, invalid_flags = 0;
 
     if (migrate_mapped_ram()) {
         invalid_flags |= (RAM_SAVE_FLAG_HOOK | RAM_SAVE_FLAG_MULTIFD_FLUSH |
@@ -4317,17 +4317,6 @@ static int ram_load_precopy(QEMUFile *f)
         void *host = NULL, *host_bak = NULL;
         uint8_t ch;
 
-        /*
-         * Yield periodically to let main loop run, but an iteration of
-         * the main loop is expensive, so do it each some iterations
-         */
-        if ((i & 32767) == 0 && qemu_in_coroutine()) {
-            aio_co_schedule(qemu_get_current_aio_context(),
-                            qemu_coroutine_self());
-            qemu_coroutine_yield();
-        }
-        i++;
-
         addr = qemu_get_be64(f);
         ret = qemu_file_get_error(f);
         if (ret) {
-- 
2.50.1



  parent reply	other threads:[~2025-10-22 19:27 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-22 19:25 [PATCH 00/13] migration: Threadify loadvm process Peter Xu
2025-10-22 19:26 ` [PATCH 01/13] io: Add qio_channel_wait_cond() helper Peter Xu
2025-10-23 13:02   ` Vladimir Sementsov-Ogievskiy
2025-10-24 12:00   ` Daniel P. Berrangé
2025-10-22 19:26 ` [PATCH 02/13] migration: Properly wait on G_IO_IN when peeking messages Peter Xu
2025-10-23 13:07   ` Vladimir Sementsov-Ogievskiy
2025-10-24 12:02   ` Daniel P. Berrangé
2025-10-28 18:16     ` Peter Xu
2025-10-22 19:26 ` [PATCH 03/13] migration/rdma: Fix wrong context in qio_channel_rdma_shutdown() Peter Xu
2025-10-22 19:26 ` [PATCH 04/13] migration/rdma: Allow qemu_rdma_wait_comp_channel work with thread Peter Xu
2025-10-23 13:41   ` Vladimir Sementsov-Ogievskiy
2025-10-22 19:26 ` [PATCH 05/13] migration/rdma: Change io_create_watch() to return immediately Peter Xu
2025-10-22 19:26 ` [PATCH 06/13] migration: Introduce WITH_BQL_HELD() / WITH_BQL_RELEASED() Peter Xu
2025-10-28 13:27   ` Vladimir Sementsov-Ogievskiy
2025-10-22 19:26 ` [PATCH 07/13] migration: Pass in bql_held information from qemu_loadvm_state() Peter Xu
2025-10-28 14:22   ` Vladimir Sementsov-Ogievskiy
2025-10-22 19:26 ` [PATCH 08/13] migration: Thread-ify precopy vmstate load process Peter Xu
2025-10-22 19:26 ` [PATCH 09/13] migration/rdma: Remove coroutine path in qemu_rdma_wait_comp_channel Peter Xu
2025-10-22 19:26 ` [PATCH 10/13] migration/postcopy: Remove workaround on wait preempt channel Peter Xu
2025-10-22 19:26 ` Peter Xu [this message]
2025-10-22 19:26 ` [PATCH 12/13] migration: Allow blocking mode for incoming live migration Peter Xu
2025-10-22 19:26 ` [PATCH 13/13] migration/vfio: Drop BQL dependency for loadvm SWITCHOVER_START Peter Xu
2025-10-22 19:29 ` [PATCH 00/13] migration: Threadify loadvm process Peter Xu

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