Author: Antonio Cuni <[email protected]>
Branch: vmprof
Changeset: r76540:78914547f680
Date: 2015-03-24 19:01 +0100
http://bitbucket.org/pypy/pypy/changeset/78914547f680/
Log: disable vmprof around fork(), and re-enable it only in the parent
process
diff --git a/pypy/module/_vmprof/src/vmprof.c b/pypy/module/_vmprof/src/vmprof.c
--- a/pypy/module/_vmprof/src/vmprof.c
+++ b/pypy/module/_vmprof/src/vmprof.c
@@ -26,6 +26,7 @@
#include <sys/time.h>
#include <sys/types.h>
#include <errno.h>
+#include <pthread.h>
#define UNW_LOCAL_ONLY
#include <libunwind.h>
@@ -44,6 +45,8 @@
void* vmprof_mainloop_func;
static ptrdiff_t mainloop_sp_offset;
static vmprof_get_virtual_ip_t mainloop_get_virtual_ip;
+static long last_period_usec = 0;
+static int atfork_hook_installed = 0;
/* *************************************************************
@@ -275,6 +278,7 @@
static int install_sigprof_timer(long period_usec) {
static struct itimerval timer;
+ last_period_usec = period_usec;
timer.it_interval.tv_sec = 0;
timer.it_interval.tv_usec = period_usec;
timer.it_value = timer.it_interval;
@@ -295,6 +299,34 @@
return 0;
}
+static void atfork_disable_timer(void) {
+ remove_sigprof_timer();
+}
+
+static void atfork_enable_timer(void) {
+ install_sigprof_timer(last_period_usec);
+}
+
+static int install_pthread_atfork_hooks(void) {
+ /* this is needed to prevent the problems described there:
+ - http://code.google.com/p/gperftools/issues/detail?id=278
+ - http://lists.debian.org/debian-glibc/2010/03/msg00161.html
+
+ TL;DR: if the RSS of the process is large enough, the clone() syscall
+ will be interrupted by the SIGPROF before it can complete, then
+ retried, interrupted again and so on, in an endless loop. The
+ solution is to disable the timer around the fork, and re-enable it
+ only inside the parent.
+ */
+ if (atfork_hook_installed)
+ return 0;
+ int ret = pthread_atfork(atfork_disable_timer, atfork_enable_timer, NULL);
+ if (ret != 0)
+ return -1;
+ atfork_hook_installed = 1;
+ return 0;
+}
+
/* *************************************************************
* public API
* *************************************************************
@@ -321,6 +353,9 @@
if (install_sigprof_timer(period_usec) == -1) {
return -1;
}
+ if (install_pthread_atfork_hooks() == -1) {
+ return -1;
+ }
return 0;
}
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