Date: Sun, 04 Nov 2007 13:46:49 +0200 From: Danny Braniss <danny@cs.huji.ac.il> To: iedowse@FreeBSD.org Cc: freebsd-bugs@FreeBSD.org Subject: Re: bin/117603: [patch] dump(8) hangs on SMP - 4way and higher. Message-ID: <E1IodwH-000GBl-Qc@cs1.cs.huji.ac.il> In-Reply-To: Your message of Sun, 4 Nov 2007 11:27:51 GMT .
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--==_Exmh_1194176785_547800
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wups, sent an old diffs.
--==_Exmh_1194176785_547800
Content-Type: text/plain ; name="dump.c.diffs"; charset=us-ascii
Content-Description: dump.c.diffs
Content-Disposition: attachment; filename="dump.c.diffs"
--- tape.c.orig Wed Mar 2 04:30:08 2005
+++ tape.c Sun Nov 4 13:42:55 2007
@@ -109,11 +109,6 @@
int master; /* pid of master, for sending error signals */
int tenths; /* length of tape used per block written */
-static volatile sig_atomic_t caught; /* have we caught the signal to proceed? */
-static volatile sig_atomic_t ready; /* reached the lock point without having */
- /* received the SIGUSR2 signal from the prev slave? */
-static jmp_buf jmpbuf; /* where to jump to if we are ready when the */
- /* SIGUSR2 arrives from the previous slave */
int
alloctape(void)
@@ -685,15 +680,13 @@
void
proceed(int signo __unused)
{
-
- if (ready)
- longjmp(jmpbuf, 1);
- caught++;
+ // do nothing ...
}
void
enslave(void)
{
+ sigset_t s_mask;
int cmd[2];
int i, j;
@@ -704,13 +697,11 @@
signal(SIGUSR1, tperror); /* Slave sends SIGUSR1 on tape errors */
signal(SIGUSR2, proceed); /* Slave sends SIGUSR2 to next slave */
- for (i = 0; i < SLAVES; i++) {
- if (i == slp - &slaves[0]) {
- caught = 1;
- } else {
- caught = 0;
- }
+ sigemptyset(&s_mask);
+ sigaddset(&s_mask, SIGUSR2);
+ sigprocmask(SIG_BLOCK, &s_mask, NULL);
+ for (i = 0; i < SLAVES; i++) {
if (socketpair(AF_UNIX, SOCK_STREAM, 0, cmd) < 0 ||
(slaves[i].pid = fork()) < 0)
quit("too many slaves, %d (recompile smaller): %s\n",
@@ -733,6 +724,7 @@
sizeof slaves[0].pid);
master = 0;
+ kill(slp->pid, SIGUSR2); // start the ball rolling
}
void
@@ -757,6 +749,7 @@
static void
doslave(int cmd, int slave_number)
{
+ sigset_t s_mask;
int nread;
int nextslave, size, wrote, eot_count;
@@ -774,7 +767,7 @@
!= sizeof nextslave) {
quit("master/slave protocol botched - didn't get pid of next slave.\n");
}
-
+ sigemptyset(&s_mask);
/*
* Get list of blocks to dump, read the blocks into tape buffer
*/
@@ -793,14 +786,7 @@
quit("master/slave protocol botched.\n");
}
}
- if (setjmp(jmpbuf) == 0) {
- ready = 1;
- if (!caught)
- (void) pause();
- }
- ready = 0;
- caught = 0;
-
+ sigsuspend(&s_mask);
/* Try to write the data... */
eot_count = 0;
size = 0;
--==_Exmh_1194176785_547800--
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