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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V2] Switch to poll() in cxenstored's IO loop
On Tue, 2013-01-29 at 17:40 +0000, Wei Liu wrote:
> Ian, ping?
It's in my queue but I've been holding off applying until we get a test
pass and push, we've got a weeks worth of stuff in the staging queue at
the moment.
Ian.
>
> On Tue, 2013-01-22 at 15:18 +0000, Wei Liu wrote:
> > commit 14b82f52d40143019094727b8fa1aa3a111ffab3
> > Author: Wei Liu <wei.liu2@xxxxxxxxxx>
> > Date: Mon Jan 21 19:07:37 2013 +0000
> >
> > Switch to poll() in cxenstored's IO loop
> >
> > Poll() can support more file descriptors than select(). We've done this
> > for
> > xenconsoled, now do this for cxenstored as well.
> >
> > The code is taken from xenconsoled and modified to adapt to cxenstored.
> >
> > Updated:
> > * reopen pipe if polling on reopen_log_pipe fails.
> > * exit if polling on some critical fds fails.
> >
> > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
> >
> > diff --git a/tools/xenstore/xenstored_core.c
> > b/tools/xenstore/xenstored_core.c
> > index bd44645..b91704e 100644
> > --- a/tools/xenstore/xenstored_core.c
> > +++ b/tools/xenstore/xenstored_core.c
> > @@ -19,7 +19,7 @@
> >
> > #include <sys/types.h>
> > #include <sys/stat.h>
> > -#include <sys/select.h>
> > +#include <poll.h>
> > #ifndef NO_SOCKETS
> > #include <sys/socket.h>
> > #include <sys/un.h>
> > @@ -55,6 +55,12 @@
> > #include "hashtable.h"
> >
> > extern xc_evtchn *xce_handle; /* in xenstored_domain.c */
> > +static struct pollfd *xce_pollfd;
> > +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 bool verbose = false;
> > LIST_HEAD(connections);
> > @@ -62,6 +68,7 @@ static int tracefd = -1;
> > static bool recovery = true;
> > static bool remove_local = true;
> > static int reopen_log_pipe[2];
> > +static struct pollfd *reopen_log_pipe0_pollfd;
> > static char *tracefile = NULL;
> > static TDB_CONTEXT *tdb_ctx = NULL;
> >
> > @@ -199,7 +206,7 @@ void trace_destroy(const void *data, const char *type)
> > /**
> > * Signal handler for SIGHUP, which requests that the trace log is reopened
> > * (in the main loop). A single byte is written to reopen_log_pipe, to
> > awaken
> > - * the select() in the main loop.
> > + * the poll() in the main loop.
> > */
> > static void trigger_reopen_log(int signal __attribute__((unused)))
> > {
> > @@ -279,15 +286,12 @@ static int destroy_conn(void *_conn)
> >
> > /* Flush outgoing if possible, but don't block. */
> > if (!conn->domain) {
> > - fd_set set;
> > - struct timeval none;
> > -
> > - FD_ZERO(&set);
> > - FD_SET(conn->fd, &set);
> > - none.tv_sec = none.tv_usec = 0;
> > + struct pollfd pfd;
> > + pfd.fd = conn->fd;
> > + pfd.events = POLLOUT;
> >
> > while (!list_empty(&conn->out_list)
> > - && select(conn->fd+1, NULL, &set, NULL, &none) == 1)
> > + && poll(&pfd, 1, 0) == 1)
> > if (!write_messages(conn))
> > break;
> > close(conn->fd);
> > @@ -300,52 +304,74 @@ static int destroy_conn(void *_conn)
> > }
> >
> >
> > -static void set_fd(int fd, fd_set *set, int *max)
> > +static struct pollfd *set_fd(int fd, short events)
> > {
> > - if (fd < 0)
> > - return;
> > - FD_SET(fd, set);
> > - if (fd > *max)
> > - *max = fd;
> > -}
> > + 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;
> >
> > -static int initialize_set(fd_set *inset, fd_set *outset, int sock, int
> > ro_sock,
> > - struct timeval **ptimeout)
> > + 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:
> > + syslog(LOG_ERR, "realloc failed, ignoring fd %d\n", fd);
> > + return NULL;
> > +}
> > +
> > +static void initialize_fds(int sock, struct pollfd **p_sock_pollfd,
> > + int ro_sock, struct pollfd **p_ro_sock_pollfd,
> > + int *ptimeout)
> > {
> > - static struct timeval zero_timeout = { 0 };
> > struct connection *conn;
> > - int max = -1;
> >
> > - *ptimeout = NULL;
> > + memset(fds, 0, sizeof(struct pollfd) * current_array_size);
> > + nr_fds = 0;
> >
> > - FD_ZERO(inset);
> > - FD_ZERO(outset);
> > + *ptimeout = -1;
> >
> > if (sock != -1)
> > - set_fd(sock, inset, &max);
> > + *p_sock_pollfd = set_fd(sock, POLLIN|POLLPRI);
> > if (ro_sock != -1)
> > - set_fd(ro_sock, inset, &max);
> > + *p_ro_sock_pollfd = set_fd(ro_sock, POLLIN|POLLPRI);
> > if (reopen_log_pipe[0] != -1)
> > - set_fd(reopen_log_pipe[0], inset, &max);
> > + reopen_log_pipe0_pollfd =
> > + set_fd(reopen_log_pipe[0], POLLIN|POLLPRI);
> >
> > if (xce_handle != NULL)
> > - set_fd(xc_evtchn_fd(xce_handle), inset, &max);
> > + xce_pollfd = set_fd(xc_evtchn_fd(xce_handle), POLLIN|POLLPRI);
> >
> > list_for_each_entry(conn, &connections, list) {
> > if (conn->domain) {
> > if (domain_can_read(conn) ||
> > (domain_can_write(conn) &&
> > !list_empty(&conn->out_list)))
> > - *ptimeout = &zero_timeout;
> > + *ptimeout = 0;
> > } else {
> > - set_fd(conn->fd, inset, &max);
> > + short events = POLLIN|POLLPRI;
> > if (!list_empty(&conn->out_list))
> > - FD_SET(conn->fd, outset);
> > + events |= POLLOUT;
> > + conn->pollfd = set_fd(conn->fd, events);
> > }
> > }
> > -
> > - return max;
> > }
> >
> > /* Is child a subnode of parent, or equal? */
> > @@ -1770,14 +1796,13 @@ int priv_domid = 0;
> >
> > int main(int argc, char *argv[])
> > {
> > - int opt, *sock, *ro_sock, max;
> > - fd_set inset, outset;
> > + int opt, *sock, *ro_sock;
> > + struct pollfd *sock_pollfd = NULL, *ro_sock_pollfd = NULL;
> > bool dofork = true;
> > bool outputpid = false;
> > bool no_domain_init = false;
> > const char *pidfile = NULL;
> > - int evtchn_fd = -1;
> > - struct timeval *timeout;
> > + int timeout;
> >
> > while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:T:RLVW:", options,
> > NULL)) != -1) {
> > @@ -1880,11 +1905,9 @@ int main(int argc, char *argv[])
> >
> > signal(SIGHUP, trigger_reopen_log);
> >
> > - if (xce_handle != NULL)
> > - evtchn_fd = xc_evtchn_fd(xce_handle);
> > -
> > /* Get ready to listen to the tools. */
> > - max = initialize_set(&inset, &outset, *sock, *ro_sock, &timeout);
> > + initialize_fds(*sock, &sock_pollfd, *ro_sock, &ro_sock_pollfd,
> > + &timeout);
> >
> > /* Tell the kernel we're up and running. */
> > xenbus_notify_running();
> > @@ -1893,27 +1916,55 @@ int main(int argc, char *argv[])
> > for (;;) {
> > struct connection *conn, *next;
> >
> > - if (select(max+1, &inset, &outset, NULL, timeout) < 0) {
> > + if (poll(fds, nr_fds, timeout) < 0) {
> > if (errno == EINTR)
> > continue;
> > - barf_perror("Select failed");
> > + barf_perror("Poll failed");
> > }
> >
> > - if (reopen_log_pipe[0] != -1 && FD_ISSET(reopen_log_pipe[0],
> > &inset)) {
> > - char c;
> > - if (read(reopen_log_pipe[0], &c, 1) != 1)
> > - barf_perror("read failed");
> > - reopen_log();
> > + if (reopen_log_pipe0_pollfd) {
> > + if (reopen_log_pipe0_pollfd->revents &
> > ~(POLLIN|POLLOUT|POLLPRI)) {
> > + close(reopen_log_pipe[0]);
> > + close(reopen_log_pipe[1]);
> > + init_pipe(reopen_log_pipe);
> > + } else if (reopen_log_pipe0_pollfd->revents & POLLIN) {
> > + char c;
> > + if (read(reopen_log_pipe[0], &c, 1) != 1)
> > + barf_perror("read failed");
> > + reopen_log();
> > + }
> > + reopen_log_pipe0_pollfd = NULL;
> > }
> >
> > - if (*sock != -1 && FD_ISSET(*sock, &inset))
> > - accept_connection(*sock, true);
> > + if (sock_pollfd) {
> > + if (sock_pollfd->revents & ~(POLLIN|POLLOUT|POLLPRI)) {
> > + barf_perror("sock poll failed");
> > + break;
> > + } else if (sock_pollfd->revents & POLLIN) {
> > + accept_connection(*sock, true);
> > + sock_pollfd = NULL;
> > + }
> > + }
> >
> > - if (*ro_sock != -1 && FD_ISSET(*ro_sock, &inset))
> > - accept_connection(*ro_sock, false);
> > + if (ro_sock_pollfd) {
> > + if (ro_sock_pollfd->revents &
> > ~(POLLIN|POLLOUT|POLLPRI)) {
> > + barf_perror("ro sock poll failed");
> > + break;
> > + } else if (ro_sock_pollfd->revents & POLLIN) {
> > + accept_connection(*ro_sock, false);
> > + ro_sock_pollfd = NULL;
> > + }
> > + }
> >
> > - if (evtchn_fd != -1 && FD_ISSET(evtchn_fd, &inset))
> > - handle_event();
> > + if (xce_pollfd) {
> > + if (xce_pollfd->revents & ~(POLLIN|POLLOUT|POLLPRI)) {
> > + barf_perror("xce_handle poll failed");
> > + break;
> > + } else if (xce_pollfd->revents & POLLIN) {
> > + handle_event();
> > + xce_pollfd = NULL;
> > + }
> > + }
> >
> > next = list_entry(connections.next, typeof(*conn), list);
> > if (&next->list != &connections)
> > @@ -1939,21 +1990,27 @@ int main(int argc, char *argv[])
> > if (talloc_free(conn) == 0)
> > continue;
> > } else {
> > - if (FD_ISSET(conn->fd, &inset))
> > + if (conn->pollfd &&
> > + !(conn->pollfd->revents &
> > ~(POLLIN|POLLOUT|POLLPRI)) &&
> > + (conn->pollfd->revents & POLLIN))
> > handle_input(conn);
> > if (talloc_free(conn) == 0)
> > continue;
> >
> > talloc_increase_ref_count(conn);
> > - if (FD_ISSET(conn->fd, &outset))
> > + if (conn->pollfd &&
> > + !(conn->pollfd->revents &
> > ~(POLLIN|POLLOUT|POLLPRI)) &&
> > + (conn->pollfd->revents & POLLOUT))
> > handle_output(conn);
> > if (talloc_free(conn) == 0)
> > continue;
> > +
> > + conn->pollfd = NULL;
> > }
> > }
> >
> > - max = initialize_set(&inset, &outset, *sock, *ro_sock,
> > - &timeout);
> > + initialize_fds(*sock, &sock_pollfd, *ro_sock, &ro_sock_pollfd,
> > + &timeout);
> > }
> > }
> >
> > diff --git a/tools/xenstore/xenstored_core.h
> > b/tools/xenstore/xenstored_core.h
> > index 492ca0d..f330a87 100644
> > --- a/tools/xenstore/xenstored_core.h
> > +++ b/tools/xenstore/xenstored_core.h
> > @@ -60,6 +60,8 @@ struct connection
> >
> > /* The file descriptor we came in on. */
> > int fd;
> > + /* The pollfd corresponding to fd. */
> > + struct pollfd *pollfd;
> >
> > /* Who am I? 0 for socket connections. */
> > unsigned int id;
> >
> >
>
>
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