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[Qemu-devel] [PATCH 1/2] migrate.c: migrate_fd_put_buffer(): Do not busy
From: |
Uri Lublin |
Subject: |
[Qemu-devel] [PATCH 1/2] migrate.c: migrate_fd_put_buffer(): Do not busyloop: stop writing if EWOULDBLOCK |
Date: |
Tue, 3 Feb 2009 13:04:22 +0200 |
Theoretically the migration code is non-blocking, designed for live migration.
Practically migrate_fd_put_buffer busy-loops trying to write. That's since
on many machines EWOULDBLOCK==EAGAIN (e.g. look in
<linux>/include/asm-generic/errno.h).
Busy looping is much worse then blocking (in case a write actually blocks).
Fixed by removing "(s->get_error(s)) == EWOULDBLOCK)" from the while condition.
Signed-off-by: Uri Lublin <address@hidden>
---
migration.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/migration.c b/migration.c
index 0ef777a..e8bafa6 100644
--- a/migration.c
+++ b/migration.c
@@ -168,7 +168,7 @@ ssize_t migrate_fd_put_buffer(void *opaque, const void
*data, size_t size)
do {
ret = s->write(s, data, size);
- } while (ret == -1 && ((s->get_error(s)) == EINTR || (s->get_error(s)) ==
EWOULDBLOCK));
+ } while (ret == -1 && s->get_error(s) == EINTR);
if (ret == -1)
ret = -(s->get_error(s));
--
1.6.0.6
- [Qemu-devel] [PATCH 1/2] migrate.c: migrate_fd_put_buffer(): Do not busyloop: stop writing if EWOULDBLOCK,
Uri Lublin <=