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-rw-r--r--kernel/kmod.c40
1 files changed, 18 insertions, 22 deletions
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 563f97e2be36..ff68198fe83b 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -45,8 +45,6 @@
#include <trace/events/module.h>
-extern int max_threads;
-
#define CAP_BSET (void *)1
#define CAP_PI (void *)2
@@ -56,6 +54,20 @@ static DEFINE_SPINLOCK(umh_sysctl_lock);
static DECLARE_RWSEM(umhelper_sem);
#ifdef CONFIG_MODULES
+/*
+ * Assuming:
+ *
+ * threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE,
+ * (u64) THREAD_SIZE * 8UL);
+ *
+ * If you need less than 50 threads would mean we're dealing with systems
+ * smaller than 3200 pages. This assuems you are capable of having ~13M memory,
+ * and this would only be an be an upper limit, after which the OOM killer
+ * would take effect. Systems like these are very unlikely if modules are
+ * enabled.
+ */
+#define MAX_KMOD_CONCURRENT 50
+static atomic_t kmod_concurrent_max = ATOMIC_INIT(MAX_KMOD_CONCURRENT);
/*
modprobe_path is set via /proc/sys.
@@ -127,10 +139,7 @@ int __request_module(bool wait, const char *fmt, ...)
{
va_list args;
char module_name[MODULE_NAME_LEN];
- unsigned int max_modprobes;
int ret;
- static atomic_t kmod_concurrent = ATOMIC_INIT(0);
-#define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
static int kmod_loop_msg;
/*
@@ -154,21 +163,7 @@ int __request_module(bool wait, const char *fmt, ...)
if (ret)
return ret;
- /* If modprobe needs a service that is in a module, we get a recursive
- * loop. Limit the number of running kmod threads to max_threads/2 or
- * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method
- * would be to run the parents of this process, counting how many times
- * kmod was invoked. That would mean accessing the internals of the
- * process tables to get the command line, proc_pid_cmdline is static
- * and it is not worth changing the proc code just to handle this case.
- * KAO.
- *
- * "trace the ppid" is simple, but will fail if someone's
- * parent exits. I think this is as good as it gets. --RR
- */
- max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT);
- atomic_inc(&kmod_concurrent);
- if (atomic_read(&kmod_concurrent) > max_modprobes) {
+ if (atomic_dec_if_positive(&kmod_concurrent_max) < 0) {
/* We may be blaming an innocent here, but unlikely */
if (kmod_loop_msg < 5) {
printk(KERN_ERR
@@ -176,7 +171,6 @@ int __request_module(bool wait, const char *fmt, ...)
module_name);
kmod_loop_msg++;
}
- atomic_dec(&kmod_concurrent);
return -ENOMEM;
}
@@ -184,10 +178,12 @@ int __request_module(bool wait, const char *fmt, ...)
ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
- atomic_dec(&kmod_concurrent);
+ atomic_inc(&kmod_concurrent_max);
+
return ret;
}
EXPORT_SYMBOL(__request_module);
+
#endif /* CONFIG_MODULES */
static void call_usermodehelper_freeinfo(struct subprocess_info *info)