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[Qemu-devel] [PATCH 11/12] migration: handle EAGAIN while reading QEMUFi
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 11/12] migration: handle EAGAIN while reading QEMUFile |
Date: |
Thu, 18 Oct 2012 12:22:37 +0200 |
This will never happen right now (the assertion would fail). The
next patch will set the socket or pipe in non-blocking mode, thus
enabling this part of the code.
Coroutines can just stop whenever they want with qemu_coroutine_yield.
As soon as select tells the main loop that the migration stream is
readable, the coroutine is re-entered directly in qemu_get_buffer,
where it will read more data and pass it to the loading routines.
Signed-off-by: Paolo Bonzini <address@hidden>
---
savevm.c | 30 ++++++++++++++++++++++++------
1 file modificato, 24 inserzioni(+), 6 rimozioni(-)
diff --git a/savevm.c b/savevm.c
index ae5e617..783bb3c 100644
--- a/savevm.c
+++ b/savevm.c
@@ -199,13 +199,22 @@ static int socket_get_buffer(void *opaque, uint8_t *buf,
int64_t pos, int size)
QEMUFileSocket *s = opaque;
ssize_t len;
- do {
+ for (;;) {
len = qemu_recv(s->fd, buf, size, 0);
- } while (len == -1 && socket_error() == EINTR);
+ if (len != -1) {
+ break;
+ }
+ if (errno == EAGAIN) {
+ assert(qemu_in_coroutine());
+ qemu_coroutine_yield();
+ } else if (errno != EINTR) {
+ break;
+ }
+ }
- if (len == -1)
+ if (len == -1) {
len = -socket_error();
-
+ }
return len;
}
@@ -236,10 +245,19 @@ static int stdio_get_buffer(void *opaque, uint8_t *buf,
int64_t pos, int size)
FILE *fp = s->stdio_file;
int bytes;
- do {
+ for (;;) {
clearerr(fp);
bytes = fread(buf, 1, size, fp);
- } while ((bytes == 0) && ferror(fp) && (errno == EINTR));
+ if (bytes != 0 || !ferror(fp)) {
+ break;
+ }
+ if (errno == EAGAIN) {
+ assert(qemu_in_coroutine());
+ qemu_coroutine_yield();
+ } else if (errno != EINTR) {
+ break;
+ }
+ }
return bytes;
}
--
1.7.12.1
- [Qemu-devel] [PATCH 06/12] migration: use migrate_fd_close in migrate_fd_cleanup, (continued)
- [Qemu-devel] [PATCH 06/12] migration: use migrate_fd_close in migrate_fd_cleanup, Paolo Bonzini, 2012/10/18
- [Qemu-devel] [PATCH 09/12] migration: close socket QEMUFile from socket_close, Paolo Bonzini, 2012/10/18
- [Qemu-devel] [PATCH 07/12] migration: use closesocket, not close, Paolo Bonzini, 2012/10/18
- [Qemu-devel] [PATCH 08/12] migration: xxx_close will only be called once, Paolo Bonzini, 2012/10/18
- [Qemu-devel] [PATCH 10/12] migration: move qemu_fclose to process_incoming_migration, Paolo Bonzini, 2012/10/18
- [Qemu-devel] [PATCH 11/12] migration: handle EAGAIN while reading QEMUFile,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 12/12] migration: move process_incoming_migration to a coroutine, Paolo Bonzini, 2012/10/18