tadd some annoying lock loop prints -- let's see if they ever fire. - plan9port - [fork] Plan 9 from user space
(HTM) git clone git://src.adamsgaard.dk/plan9port
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---
(DIR) commit a620761c92f49d2738f99fab206a4c61a89394cf
(DIR) parent af89fc108d61625959704a08ffdd44adfd86a9d4
(HTM) Author: rsc <devnull@localhost>
Date: Thu, 6 Jan 2005 23:08:55 +0000
add some annoying lock loop prints -- let's see
if they ever fire.
also fix race in delaystack. it was actually happening!
tthat just goes to show that while i can reason very well
about what can and cannot happen, i have no intuition
at all for how likely they are.
Diffstat:
M src/libthread/Linux.c | 73 +++++++++++++++++++++++++++----
1 file changed, 65 insertions(+), 8 deletions(-)
---
(DIR) diff --git a/src/libthread/Linux.c b/src/libthread/Linux.c
t@@ -1,5 +1,19 @@
#include "threadimpl.h"
+static int
+timefmt(Fmt *fmt)
+{
+ static char *mon[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+ "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
+ vlong ns;
+ Tm tm;
+ ns = nsec();
+ tm = *localtime(time(0));
+ return fmtprint(fmt, "%s %2d %02d:%02d:%02d.%03d",
+ mon[tm.mon], tm.mday, tm.hour, tm.min, tm.sec,
+ (int)(ns%1000000000)/1000000);
+}
+
/*
* spin locks
*/
t@@ -17,6 +31,8 @@ int
_threadlock(Lock *l, int block, ulong pc)
{
int i;
+static int first=1;
+if(first) {first=0; fmtinstall('T', timefmt);}
USED(pc);
t@@ -27,17 +43,48 @@ _threadlock(Lock *l, int block, ulong pc)
return 0;
/* a thousand times pretty fast */
- for(i=0; i<1000; i++){
+ for(i=0; i<10*1000; i++){
if(!_tas(&l->held))
return 1;
sched_yield();
}
/* now nice and slow */
+ for(i=0; i<10; i++){
+ if(!_tas(&l->held))
+ return 1;
+ usleep(1);
+ }
+fprint(2, "%T lock loop %p from %lux\n", l, pc);
+ for(i=0; i<10; i++){
+ if(!_tas(&l->held))
+ return 1;
+ usleep(10);
+ }
+fprint(2, "%T lock loop %p from %lux\n", l, pc);
+ for(i=0; i<10; i++){
+ if(!_tas(&l->held))
+ return 1;
+ usleep(100);
+ }
+fprint(2, "%T lock loop %p from %lux\n", l, pc);
+ for(i=0; i<10; i++){
+ if(!_tas(&l->held))
+ return 1;
+ usleep(1000);
+ }
+fprint(2, "%T lock loop %p from %lux\n", l, pc);
+ for(i=0; i<10; i++){
+ if(!_tas(&l->held))
+ return 1;
+ usleep(10*1000);
+ }
+fprint(2, "%T lock loop %p from %lux\n", l, pc);
for(i=0; i<1000; i++){
if(!_tas(&l->held))
return 1;
usleep(100*1000);
}
+fprint(2, "%T lock loop %p from %lux\n", l, pc);
/* take your time */
while(_tas(&l->held))
usleep(1000*1000);
t@@ -120,17 +167,19 @@ struct Stackfree
{
Stackfree *next;
int pid;
+ int pid1;
};
static Lock stacklock;
static Stackfree *stackfree;
static void
-delayfreestack(uchar *stk)
+delayfreestack(uchar *stk, int pid, int pid1)
{
Stackfree *sf;
sf = (Stackfree*)stk;
- sf->pid = getpid();
+ sf->pid = pid;
+ sf->pid1 = pid1;
lock(&stacklock);
sf->next = stackfree;
stackfree = sf;
t@@ -147,7 +196,8 @@ dofreestacks(void)
for(last=nil,sf=stackfree; sf; last=sf,sf=next){
next = sf->next;
- if(sf->pid >= 1 && kill(sf->pid, 0) < 0 && errno == ESRCH){
+ if(sf->pid >= 1 && kill(sf->pid, 0) < 0 && errno == ESRCH)
+ if(sf->pid1 >= 1 && kill(sf->pid1, 0) < 0 && errno == ESRCH){
free(sf);
if(last)
last->next = next;
t@@ -166,17 +216,20 @@ startprocfn(void *v)
uchar *stk;
void (*fn)(void*);
Proc *p;
+ int pid0, pid1;
a = (void**)v;
fn = a[0];
p = a[1];
stk = a[2];
+ pid0 = (int)a[4];
+ pid1 = getpid();
free(a);
- p->osprocid = getpid();
+ p->osprocid = pid1;
(*fn)(p);
- delayfreestack(stk);
+ delayfreestack(stk, pid0, pid1);
_exit(0);
return 0;
}
t@@ -191,9 +244,12 @@ static int
trampnowait(void *v)
{
void **a;
+ int *kidpid;
a = (void*)v;
- *(int*)a[3] = clone(startprocfn, a[2]+65536-512, CLONE_VM|CLONE_FILES, a);
+ kidpid = a[3];
+ a[4] = (void*)getpid();
+ *kidpid = clone(startprocfn, a[2]+65536-512, CLONE_VM|CLONE_FILES, a);
_exit(0);
return 0;
}
t@@ -206,7 +262,7 @@ _procstart(Proc *p, void (*fn)(Proc*))
int pid, kidpid, status;
dofreestacks();
- a = malloc(4*sizeof a[0]);
+ a = malloc(5*sizeof a[0]);
if(a == nil)
sysfatal("_procstart malloc: %r");
stk = malloc(65536);
t@@ -353,3 +409,4 @@ _threadpexit(void)
{
_exit(0);
}
+