+++ /dev/null
-/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
- * vim:expandtab:shiftwidth=8:tabstop=8:
- *
- * Copyright (c) 2002 Cray Inc.
- * Copyright (c) 2002 Eric Hoffman
- *
- * This file is part of Lustre, http://www.lustre.org.
- *
- * Lustre is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * Lustre is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Lustre; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- */
-
-/* select.c:
- * Provides a general mechanism for registering and dispatching
- * io events through the select system call.
- */
-
-#ifdef sun
-#include <sys/filio.h>
-#else
-#include <sys/ioctl.h>
-#endif
-
-#include <sys/time.h>
-#include <sys/types.h>
-#include <stdlib.h>
-#include <syscall.h>
-#include <pthread.h>
-#include <errno.h>
-#include <pqtimer.h>
-#include <dispatch.h>
-#include <procbridge.h>
-
-
-static struct timeval beginning_of_epoch;
-static io_handler io_handlers;
-
-/* Function: now
- *
- * Return: the current time in canonical units: a 64 bit number
- * where the most significant 32 bits contains the number
- * of seconds, and the least signficant a count of (1/(2^32))ths
- * of a second.
- */
-when now()
-{
- struct timeval result;
-
- gettimeofday(&result,0);
- return((((unsigned long long)result.tv_sec)<<32)|
- (((unsigned long long)result.tv_usec)<<32)/1000000);
-}
-
-
-/* Function: register_io_handler
- * Arguments: fd: the file descriptor of interest
- * type: a mask of READ_HANDLER, WRITE_HANDLER, EXCEPTION_HANDLER
- * function: a function to call when io is available on fd
- * arg: an opaque correlator to return to the handler
- * Returns: a pointer to the io_handler structure
- */
-io_handler register_io_handler(int fd,
- int type,
- int (*function)(void *),
- void *arg)
-{
- io_handler i=(io_handler)malloc(sizeof(struct io_handler));
- if ((i->fd=fd)>=0){
- i->type=type;
- i->function=function;
- i->argument=arg;
- i->disabled=0;
- i->last=&io_handlers;
- if ((i->next=io_handlers)) i->next->last=&i->next;
- io_handlers=i;
- }
- return(i);
-}
-
-/* Function: remove_io_handler
- * Arguments: i: a pointer to the handler to stop servicing
- *
- * remove_io_handler() doesn't actually free the handler, due
- * to reentrancy problems. it just marks the handler for
- * later cleanup by the blocking function.
- */
-void remove_io_handler (io_handler i)
-{
- i->disabled=1;
-}
-
-static void set_flag(io_handler n,fd_set *r, fd_set *w, fd_set *e)
-{
- if (n->type & READ_HANDLER) FD_SET(n->fd, r);
- if (n->type & WRITE_HANDLER) FD_SET(n->fd, w);
- if (n->type & EXCEPTION_HANDLER) FD_SET(n->fd, e);
-}
-
-static int prepare_fd_sets(fd_set *r, fd_set *w, fd_set *e)
-{
- io_handler j;
- io_handler *k;
- int max = 0;
-
- FD_ZERO(r);
- FD_ZERO(w);
- FD_ZERO(e);
- for (k=&io_handlers;*k;){
- if ((*k)->disabled){
- j=*k;
- *k=(*k)->next;
- free(j);
- }
- if (*k) {
- set_flag(*k,r,w,e);
- if ((*k)->fd > max)
- max = (*k)->fd;
- k=&(*k)->next;
- }
- }
- return max + 1;
-}
-
-static int execute_callbacks(fd_set *r, fd_set *w, fd_set *e)
-{
- io_handler j;
- int n = 0, t;
-
- for (j = io_handlers; j; j = j->next) {
- if (j->disabled)
- continue;
-
- t = 0;
- if (FD_ISSET(j->fd, r) && (j->type & READ_HANDLER)) {
- FD_CLR(j->fd, r);
- t++;
- }
- if (FD_ISSET(j->fd, w) && (j->type & WRITE_HANDLER)) {
- FD_CLR(j->fd, w);
- t++;
- }
- if (FD_ISSET(j->fd, e) && (j->type & EXCEPTION_HANDLER)) {
- FD_CLR(j->fd, e);
- t++;
- }
- if (t == 0)
- continue;
-
- if (!(*j->function)(j->argument))
- j->disabled = 1;
-
- n += t;
- }
-
- return n;
-}
-
-#ifdef ENABLE_SELECT_DISPATCH
-
-static struct {
- pthread_mutex_t mutex;
- pthread_cond_t cond;
- int submitted;
- int nready;
- int maxfd;
- fd_set *rset;
- fd_set *wset;
- fd_set *eset;
- struct timeval *timeout;
- struct timeval submit_time;
-} fd_extra = {
- PTHREAD_MUTEX_INITIALIZER,
- PTHREAD_COND_INITIALIZER,
- 0, 0, 0,
- NULL, NULL, NULL, NULL,
-};
-
-extern int liblustre_wait_event(int timeout);
-extern procbridge __global_procbridge;
-
-/*
- * this will intercept syscall select() of user apps
- * such as MPI libs.
- */
-int select(int n, fd_set *rset, fd_set *wset, fd_set *eset,
- struct timeval *timeout)
-{
- LASSERT(fd_extra.submitted == 0);
-
- fd_extra.nready = 0;
- fd_extra.maxfd = n;
- fd_extra.rset = rset;
- fd_extra.wset = wset;
- fd_extra.eset = eset;
- fd_extra.timeout = timeout;
-
- liblustre_wait_event(0);
- pthread_mutex_lock(&fd_extra.mutex);
- gettimeofday(&fd_extra.submit_time, NULL);
- fd_extra.submitted = 1;
- LASSERT(__global_procbridge);
- procbridge_wakeup_nal(__global_procbridge);
-
-again:
- if (fd_extra.submitted)
- pthread_cond_wait(&fd_extra.cond, &fd_extra.mutex);
- pthread_mutex_unlock(&fd_extra.mutex);
-
- liblustre_wait_event(0);
-
- pthread_mutex_lock(&fd_extra.mutex);
- if (fd_extra.submitted)
- goto again;
- pthread_mutex_unlock(&fd_extra.mutex);
-
- LASSERT(fd_extra.nready >= 0);
- LASSERT(fd_extra.submitted == 0);
- return fd_extra.nready;
-}
-
-static int merge_fds(int max, fd_set *rset, fd_set *wset, fd_set *eset)
-{
- int i;
-
- LASSERT(rset);
- LASSERT(wset);
- LASSERT(eset);
-
- for (i = 0; i < __FD_SETSIZE/__NFDBITS; i++) {
- LASSERT(!fd_extra.rset ||
- !(__FDS_BITS(rset)[i] & __FDS_BITS(fd_extra.rset)[i]));
- LASSERT(!fd_extra.wset ||
- !(__FDS_BITS(wset)[i] & __FDS_BITS(fd_extra.wset)[i]));
- LASSERT(!fd_extra.eset ||
- !(__FDS_BITS(eset)[i] & __FDS_BITS(fd_extra.eset)[i]));
-
- if (fd_extra.rset && __FDS_BITS(fd_extra.rset)[i])
- __FDS_BITS(rset)[i] |= __FDS_BITS(fd_extra.rset)[i];
- if (fd_extra.wset && __FDS_BITS(fd_extra.wset)[i])
- __FDS_BITS(wset)[i] |= __FDS_BITS(fd_extra.wset)[i];
- if (fd_extra.eset && __FDS_BITS(fd_extra.eset)[i])
- __FDS_BITS(eset)[i] |= __FDS_BITS(fd_extra.eset)[i];
- }
-
- return (fd_extra.maxfd > max ? fd_extra.maxfd : max);
-}
-
-static inline
-int timeval_ge(struct timeval *tv1, struct timeval *tv2)
-{
- LASSERT(tv1 && tv2);
- return ((tv1->tv_sec - tv2->tv_sec) * 1000000 +
- (tv1->tv_usec - tv2->tv_usec) >= 0);
-}
-
-/*
- * choose the most recent timeout value
- */
-static struct timeval *choose_timeout(struct timeval *tv1,
- struct timeval *tv2)
-{
- if (!tv1)
- return tv2;
- else if (!tv2)
- return tv1;
-
- if (timeval_ge(tv1, tv2))
- return tv2;
- else
- return tv1;
-}
-
-/* Function: select_timer_block
- * Arguments: until: an absolute time when the select should return
- *
- * This function dispatches the various file descriptors' handler
- * functions, if the kernel indicates there is io available.
- */
-void select_timer_block(when until)
-{
- fd_set fds[3];
- struct timeval timeout;
- struct timeval *timeout_pointer, *select_timeout;
- int max, nready, nexec;
- int fd_handling;
-
-again:
- if (until) {
- when interval;
-
- interval = until - now();
- timeout.tv_sec = (interval >> 32);
- timeout.tv_usec = ((interval << 32) / 1000000) >> 32;
- timeout_pointer = &timeout;
- } else
- timeout_pointer = NULL;
-
- fd_handling = 0;
- max = prepare_fd_sets(&fds[0], &fds[1], &fds[2]);
- select_timeout = timeout_pointer;
-
- pthread_mutex_lock(&fd_extra.mutex);
- fd_handling = fd_extra.submitted;
- pthread_mutex_unlock(&fd_extra.mutex);
- if (fd_handling) {
- max = merge_fds(max, &fds[0], &fds[1], &fds[2]);
- select_timeout = choose_timeout(timeout_pointer, fd_extra.timeout);
- }
-
- /* XXX only compile for linux */
-#if __WORDSIZE == 64
- nready = syscall(SYS_select, max, &fds[0], &fds[1], &fds[2],
- select_timeout);
-#else
- nready = syscall(SYS__newselect, max, &fds[0], &fds[1], &fds[2],
- select_timeout);
-#endif
- if (nready < 0) {
- CERROR("select return err %d, errno %d\n", nready, errno);
- return;
- }
-
- if (nready) {
- nexec = execute_callbacks(&fds[0], &fds[1], &fds[2]);
- nready -= nexec;
- } else
- nexec = 0;
-
- /* even both nready & nexec are 0, we still need try to wakeup
- * upper thread since it may have timed out
- */
- if (fd_handling) {
- LASSERT(nready >= 0);
-
- pthread_mutex_lock(&fd_extra.mutex);
- if (nready) {
- if (fd_extra.rset)
- *fd_extra.rset = fds[0];
- if (fd_extra.wset)
- *fd_extra.wset = fds[1];
- if (fd_extra.eset)
- *fd_extra.eset = fds[2];
- fd_extra.nready = nready;
- fd_extra.submitted = 0;
- } else {
- struct timeval t;
-
- fd_extra.nready = 0;
- if (fd_extra.timeout) {
- gettimeofday(&t, NULL);
- if (timeval_ge(&t, &fd_extra.submit_time))
- fd_extra.submitted = 0;
- }
- }
-
- pthread_cond_signal(&fd_extra.cond);
- pthread_mutex_unlock(&fd_extra.mutex);
- }
-
- /* haven't found portals event, go back to loop if time
- * is not expired */
- if (!nexec) {
- if (timeout_pointer == NULL || now() >= until)
- goto again;
- }
-}
-
-#else /* !ENABLE_SELECT_DISPATCH */
-
-/* Function: select_timer_block
- * Arguments: until: an absolute time when the select should return
- *
- * This function dispatches the various file descriptors' handler
- * functions, if the kernel indicates there is io available.
- */
-void select_timer_block(when until)
-{
- fd_set fds[3];
- struct timeval timeout;
- struct timeval *timeout_pointer;
- int max, nready;
-
-again:
- if (until) {
- when interval;
- interval = until - now();
- timeout.tv_sec = (interval >> 32);
- timeout.tv_usec = ((interval << 32) / 1000000) >> 32;
- timeout_pointer = &timeout;
- } else
- timeout_pointer = NULL;
-
- max = prepare_fd_sets(&fds[0], &fds[1], &fds[2]);
-
- nready = select(max, &fds[0], &fds[1], &fds[2], timeout_pointer);
- if (nready > 0)
- execute_callbacks(&fds[0], &fds[1], &fds[2]);
-}
-#endif /* ENABLE_SELECT_DISPATCH */
-
-/* Function: init_unix_timer()
- * is called to initialize the library
- */
-void init_unix_timer()
-{
- io_handlers=0;
- gettimeofday(&beginning_of_epoch, 0);
- initialize_timer(select_timer_block);
-}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff