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Rather than simply waiting silently and indefinitely for all

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interrupt-driven configuration handlers to complete, print out a
diagnostic message every 60 second indicating which handlers are
still running.  Do this at most 5 times per run so as to avoid
scrolling out any useful information from the kernel message
buffer.

The interval of 60 seconds was selected based on a best guess as
to the nature of "long enough" and may want to be tuned higher
or lower depending on real-world tolerances.

MFC after:	3 days
Discussed with:	scottl
This commit is contained in:
Robert Watson 2008-07-19 19:08:35 +00:00
parent 9e859260ff
commit 1cc2bd820b
1 changed files with 35 additions and 3 deletions
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38
sys/kern/subr_autoconf.c
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@ -41,6 +41,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/systm.h>
@ -60,11 +61,36 @@ MTX_SYSINIT(intr_config_hook, &intr_config_hook_lock, "intr config", MTX_DEF);
/* ARGSUSED */
static void run_interrupt_driven_config_hooks(void *dummy);
/*
* If we wait too long for an interrupt-driven config hook to return, print
* a diagnostic.
*/
#define WARNING_INTERVAL_SECS 60
static void
run_interrupt_driven_config_hooks_warning(int warned)
{
struct intr_config_hook *hook_entry;
char namebuf[64];
long offset;
printf("run_interrupt_driven_hooks: still waiting after %d seconds "
"for", warned * WARNING_INTERVAL_SECS);
TAILQ_FOREACH(hook_entry, &intr_config_hook_list, ich_links) {
if (linker_search_symbol_name((caddr_t)hook_entry->ich_func,
namebuf, sizeof(namebuf), &offset) == 0)
printf(" %s", namebuf);
else
printf(" %p", hook_entry->ich_func);
}
printf("\n");
}
static void
run_interrupt_driven_config_hooks(dummy)
void *dummy;
{
struct intr_config_hook *hook_entry, *next_entry;
int warned;
mtx_lock(&intr_config_hook_lock);
TAILQ_FOREACH_SAFE(hook_entry, &intr_config_hook_list, ich_links,
@ -74,9 +100,16 @@ run_interrupt_driven_config_hooks(dummy)
mtx_lock(&intr_config_hook_lock);
}
warned = 0;
while (!TAILQ_EMPTY(&intr_config_hook_list)) {
msleep(&intr_config_hook_list, &intr_config_hook_lock, PCONFIG,
"conifhk", 0);
if (msleep(&intr_config_hook_list, &intr_config_hook_lock,
PCONFIG, "conifhk", WARNING_INTERVAL_SECS * hz) ==
EWOULDBLOCK && warned < 5) {
mtx_unlock(&intr_config_hook_lock);
warned++;
run_interrupt_driven_config_hooks_warning(warned);
mtx_lock(&intr_config_hook_lock);
}
}
mtx_unlock(&intr_config_hook_lock);
}
@ -135,7 +168,6 @@ config_intrhook_disestablish(hook)
#ifdef DDB
#include <ddb/ddb.h>
#include <sys/linker.h>
DB_SHOW_COMMAND(conifhk, db_show_conifhk)
{