| Submitter | Paolo Bonzini |
|---|---|
| Date | Oct. 18, 2012, 10:22 a.m. |
| Message ID | <1350555758-29988-12-git-send-email-pbonzini@redhat.com> |
| Download | mbox | patch |
| Permalink | /patch/192282/ |
| State | New |
| Headers | show |
Comments
On 10/18/2012 12:22 PM, Paolo Bonzini wrote: > 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 <pbonzini@redhat.com> > --- > 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) { socket_error() > + assert(qemu_in_coroutine()); > + qemu_coroutine_yield(); > + } else if (errno != EINTR) { socket_error() > + 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; > } > >
Patch
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; }
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 <pbonzini@redhat.com> --- savevm.c | 30 ++++++++++++++++++++++++------ 1 file modificato, 24 inserzioni(+), 6 rimozioni(-)