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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] Revert 0b9dfd067b42: Switch from select() to poll() in xenconsoled's IO loop
# HG changeset patch
# User Ian Campbell <ijc@xxxxxxxxxxxxxx>
# Date 1358072440 0
# Node ID 2347d59ea0cc1023ac0623a2b6fd39909312df88
# Parent 0b9dfd067b4259e2cb3285f279f369dd7bd2e032
Revert 0b9dfd067b42: Switch from select() to poll() in xenconsoled's IO loop
Causes issues with migration etc in test flight 14869 onwards.
Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
diff -r 0b9dfd067b42 -r 2347d59ea0cc tools/console/daemon/io.c
--- a/tools/console/daemon/io.c Fri Jan 11 12:22:30 2013 +0000
+++ b/tools/console/daemon/io.c Sun Jan 13 10:20:40 2013 +0000
@@ -28,7 +28,7 @@
#include <stdlib.h>
#include <errno.h>
#include <string.h>
-#include <poll.h>
+#include <sys/select.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
@@ -66,12 +66,9 @@ extern int discard_overflowed_data;
static int log_time_hv_needts = 1;
static int log_time_guest_needts = 1;
static int log_hv_fd = -1;
-
-static struct pollfd *fds;
-static unsigned int current_array_size;
-static unsigned int nr_fds;
-
-#define ROUNDUP(_x,_w) (((unsigned long)(_x)+(1UL<<(_w))-1) & ~((1UL<<(_w))-1))
+static evtchn_port_or_error_t log_hv_evtchn = -1;
+static xc_interface *xch; /* why does xenconsoled have two xc handles ? */
+static xc_evtchn *xce_handle = NULL;
struct buffer {
char *data;
@@ -84,9 +81,7 @@ struct buffer {
struct domain {
int domid;
int master_fd;
- struct pollfd *master_pollfd;
int slave_fd;
- struct pollfd *slave_pollfd;
int log_fd;
bool is_dead;
unsigned last_seen;
@@ -97,7 +92,6 @@ struct domain {
evtchn_port_or_error_t local_port;
evtchn_port_or_error_t remote_port;
xc_evtchn *xce_handle;
- struct pollfd *xce_pollfd;
struct xencons_interface *interface;
int event_count;
long long next_period;
@@ -775,17 +769,6 @@ static int ring_free_bytes(struct domain
return (sizeof(intf->in) - space);
}
-static void domain_handle_broken_tty(struct domain *dom, int recreate)
-{
- domain_close_tty(dom);
-
- if (recreate) {
- domain_create_tty(dom);
- } else {
- shutdown_domain(dom);
- }
-}
-
static void handle_tty_read(struct domain *dom)
{
ssize_t len = 0;
@@ -811,7 +794,13 @@ static void handle_tty_read(struct domai
* keep the slave open for the duration.
*/
if (len < 0) {
- domain_handle_broken_tty(dom, domain_is_valid(dom->domid));
+ domain_close_tty(dom);
+
+ if (domain_is_valid(dom->domid)) {
+ domain_create_tty(dom);
+ } else {
+ shutdown_domain(dom);
+ }
} else if (domain_is_valid(dom->domid)) {
prod = intf->in_prod;
for (i = 0; i < len; i++) {
@@ -839,7 +828,14 @@ static void handle_tty_write(struct doma
if (len < 1) {
dolog(LOG_DEBUG, "Write failed on domain %d: %zd, %d\n",
dom->domid, len, errno);
- domain_handle_broken_tty(dom, domain_is_valid(dom->domid));
+
+ domain_close_tty(dom);
+
+ if (domain_is_valid(dom->domid)) {
+ domain_create_tty(dom);
+ } else {
+ shutdown_domain(dom);
+ }
} else {
buffer_advance(&dom->buffer, len);
}
@@ -887,7 +883,7 @@ static void handle_xs(void)
free(vec);
}
-static void handle_hv_logs(xc_evtchn *xce_handle)
+static void handle_hv_logs(void)
{
char buffer[1024*16];
char *bufptr = buffer;
@@ -898,7 +894,7 @@ static void handle_hv_logs(xc_evtchn *xc
if ((port = xc_evtchn_pending(xce_handle)) == -1)
return;
- if (xc_readconsolering(xc, bufptr, &size, 0, 1, &index) == 0 && size >
0) {
+ if (xc_readconsolering(xch, bufptr, &size, 0, 1, &index) == 0 && size >
0) {
int logret;
if (log_time_hv)
logret = write_with_timestamp(log_hv_fd, buffer, size,
@@ -932,54 +928,18 @@ static void handle_log_reload(void)
}
}
-static struct pollfd *set_fds(int fd, short events)
-{
- struct pollfd *ret;
- if (current_array_size < nr_fds + 1) {
- struct pollfd *new_fds = NULL;
- unsigned long newsize;
-
- /* Round up to 2^8 boundary, in practice this just
- * make newsize larger than current_array_size.
- */
- newsize = ROUNDUP(nr_fds + 1, 8);
-
- new_fds = realloc(fds, sizeof(struct pollfd)*newsize);
- if (!new_fds)
- goto fail;
- fds = new_fds;
-
- memset(&fds[0] + current_array_size, 0,
- sizeof(struct pollfd) * (newsize-current_array_size));
- current_array_size = newsize;
- }
-
- fds[nr_fds].fd = fd;
- fds[nr_fds].events = events;
- ret = &fds[nr_fds];
- nr_fds++;
-
- return ret;
-fail:
- dolog(LOG_ERR, "realloc failed, ignoring fd %d\n", fd);
- return NULL;
-}
-
-static void reset_fds(void)
-{
- nr_fds = 0;
- memset(fds, 0, sizeof(struct pollfd) * current_array_size);
-}
-
void handle_io(void)
{
+ fd_set readfds, writefds;
int ret;
- evtchn_port_or_error_t log_hv_evtchn = -1;
- struct pollfd *xce_pollfd = NULL;
- struct pollfd *xs_pollfd = NULL;
- xc_evtchn *xce_handle = NULL;
if (log_hv) {
+ xch = xc_interface_open(0,0,0);
+ if (!xch) {
+ dolog(LOG_ERR, "Failed to open xc handle: %d (%s)",
+ errno, strerror(errno));
+ goto out;
+ }
xce_handle = xc_evtchn_open(NULL, 0);
if (xce_handle == NULL) {
dolog(LOG_ERR, "Failed to open xce handle: %d (%s)",
@@ -999,17 +959,21 @@ void handle_io(void)
for (;;) {
struct domain *d, *n;
- int poll_timeout; /* timeout in milliseconds */
+ int max_fd = -1;
+ struct timeval timeout;
struct timespec ts;
long long now, next_timeout = 0;
- reset_fds();
+ FD_ZERO(&readfds);
+ FD_ZERO(&writefds);
- xs_pollfd = set_fds(xs_fileno(xs), POLLIN|POLLPRI);
+ FD_SET(xs_fileno(xs), &readfds);
+ max_fd = MAX(xs_fileno(xs), max_fd);
- if (log_hv)
- xce_pollfd = set_fds(xc_evtchn_fd(xce_handle),
- POLLIN|POLLPRI);
+ if (log_hv) {
+ FD_SET(xc_evtchn_fd(xce_handle), &readfds);
+ max_fd = MAX(xc_evtchn_fd(xce_handle), max_fd);
+ }
if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0)
return;
@@ -1018,12 +982,10 @@ void handle_io(void)
/* Re-calculate any event counter allowances & unblock
domains with new allowance */
for (d = dom_head; d; d = d->next) {
- /* CS 16257:955ee4fa1345 introduces a 5ms fuzz
- * for select(), it is not clear poll() has
- * similar behavior (returning a couple of ms
- * sooner than requested) as well. Just leave
- * the fuzz here. Remove it with a separate
- * patch if necessary */
+ /* Add 5ms of fuzz since select() often returns
+ a couple of ms sooner than requested. Without
+ the fuzz we typically do an extra spin in select()
+ with a 1/2 ms timeout every other iteration */
if ((now+5) > d->next_period) {
d->next_period = now + RATE_LIMIT_PERIOD;
if (d->event_count >= RATE_LIMIT_ALLOWANCE) {
@@ -1044,101 +1006,75 @@ void handle_io(void)
!d->buffer.max_capacity ||
d->buffer.size < d->buffer.max_capacity) {
int evtchn_fd =
xc_evtchn_fd(d->xce_handle);
- d->xce_pollfd = set_fds(evtchn_fd,
- POLLIN|POLLPRI);
+ FD_SET(evtchn_fd, &readfds);
+ max_fd = MAX(evtchn_fd, max_fd);
}
}
if (d->master_fd != -1) {
- short events = 0;
if (!d->is_dead && ring_free_bytes(d))
- events |= POLLIN;
+ FD_SET(d->master_fd, &readfds);
if (!buffer_empty(&d->buffer))
- events |= POLLOUT;
-
- if (events)
- d->master_pollfd =
- set_fds(d->master_fd,
- events|POLLPRI);
+ FD_SET(d->master_fd, &writefds);
+ max_fd = MAX(d->master_fd, max_fd);
}
}
/* If any domain has been rate limited, we need to work
- out what timeout to supply to poll */
+ out what timeout to supply to select */
if (next_timeout) {
long long duration = (next_timeout - now);
if (duration <= 0) /* sanity check */
duration = 1;
- poll_timeout = (int)duration;
+ timeout.tv_sec = duration / 1000;
+ timeout.tv_usec = ((duration - (timeout.tv_sec * 1000))
+ * 1000);
}
- ret = poll(fds, nr_fds, next_timeout ? poll_timeout : -1);
+ ret = select(max_fd + 1, &readfds, &writefds, 0,
+ next_timeout ? &timeout : NULL);
if (log_reload) {
handle_log_reload();
log_reload = 0;
}
- /* Abort if poll failed, except for EINTR cases
+ /* Abort if select failed, except for EINTR cases
which indicate a possible log reload */
if (ret == -1) {
if (errno == EINTR)
continue;
- dolog(LOG_ERR, "Failure in poll: %d (%s)",
+ dolog(LOG_ERR, "Failure in select: %d (%s)",
errno, strerror(errno));
break;
}
- if (log_hv && xce_pollfd) {
- if (xce_pollfd->revents & ~(POLLIN|POLLOUT|POLLPRI)) {
- dolog(LOG_ERR,
- "Failure in poll xce_handle: %d (%s)",
- errno, strerror(errno));
- break;
- } else if (xce_pollfd->revents & POLLIN)
- handle_hv_logs(xce_handle);
- }
+ if (log_hv && FD_ISSET(xc_evtchn_fd(xce_handle), &readfds))
+ handle_hv_logs();
if (ret <= 0)
continue;
- if (xs_pollfd) {
- if (xs_pollfd->revents & ~(POLLIN|POLLOUT|POLLPRI)) {
- dolog(LOG_ERR,
- "Failure in poll xs_handle: %d (%s)",
- errno, strerror(errno));
- break;
- } else if (xs_pollfd->revents & POLLIN)
- handle_xs();
- }
+ if (FD_ISSET(xs_fileno(xs), &readfds))
+ handle_xs();
for (d = dom_head; d; d = n) {
n = d->next;
if (d->event_count < RATE_LIMIT_ALLOWANCE) {
if (d->xce_handle != NULL &&
- d->xce_pollfd &&
- !(d->xce_pollfd->revents &
- ~(POLLIN|POLLOUT|POLLPRI)) &&
- (d->xce_pollfd->revents &
- POLLIN))
- handle_ring_read(d);
+ FD_ISSET(xc_evtchn_fd(d->xce_handle),
+ &readfds))
+ handle_ring_read(d);
}
- if (d->master_fd != -1 && d->master_pollfd) {
- if (d->master_pollfd->revents &
- ~(POLLIN|POLLOUT|POLLPRI))
- domain_handle_broken_tty(d,
- domain_is_valid(d->domid));
- else {
- if (d->master_pollfd->revents &
- POLLIN)
- handle_tty_read(d);
- if (d->master_pollfd->revents &
- POLLOUT)
- handle_tty_write(d);
- }
- }
+ if (d->master_fd != -1 && FD_ISSET(d->master_fd,
+ &readfds))
+ handle_tty_read(d);
+
+ if (d->master_fd != -1 && FD_ISSET(d->master_fd,
+ &writefds))
+ handle_tty_write(d);
if (d->last_seen != enum_pass)
shutdown_domain(d);
@@ -1148,14 +1084,15 @@ void handle_io(void)
}
}
- free(fds);
- current_array_size = 0;
-
out:
if (log_hv_fd != -1) {
close(log_hv_fd);
log_hv_fd = -1;
}
+ if (xch) {
+ xc_interface_close(xch);
+ xch = 0;
+ }
if (xce_handle != NULL) {
xc_evtchn_close(xce_handle);
xce_handle = NULL;
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