aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorHeinrich Schuchardt <xypron.glpk@gmx.de>2015-04-16 12:47:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-17 09:04:06 -0400
commitff691f6e03815dc8f99461ea509df863a879fc3a (patch)
treeacc3b3c61ff40365d15cbe89952c743b301016af
parent3ea7f5e25ec271909451b7dc17be37581b888de6 (diff)
downloadlinux-stericsson-ff691f6e03815dc8f99461ea509df863a879fc3a.tar.gz
kernel/fork.c: new function for max_threads
PAGE_SIZE is not guaranteed to be equal to or less than 8 times the THREAD_SIZE. E.g. architecture hexagon may have page size 1M and thread size 4096. This would lead to a division by zero in the calculation of max_threads. With this patch the buggy code is moved to a separate function set_max_threads. The error is not fixed. After fixing the problem in a separate patch the new function can be reused to adjust max_threads after adding or removing memory. Argument mempages of function fork_init() is removed as totalram_pages is an exported symbol. The creation of separate patches for refactoring to a new function and for fixing the logic was suggested by Ingo Molnar. Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--init/main.c4
-rw-r--r--kernel/fork.c34
2 files changed, 23 insertions, 15 deletions
diff --git a/init/main.c b/init/main.c
index a7e969d12f51..2115055faeac 100644
--- a/init/main.c
+++ b/init/main.c
@@ -91,7 +91,7 @@
static int kernel_init(void *);
extern void init_IRQ(void);
-extern void fork_init(unsigned long);
+extern void fork_init(void);
extern void radix_tree_init(void);
#ifndef CONFIG_DEBUG_RODATA
static inline void mark_rodata_ro(void) { }
@@ -645,7 +645,7 @@ asmlinkage __visible void __init start_kernel(void)
#endif
thread_info_cache_init();
cred_init();
- fork_init(totalram_pages);
+ fork_init();
proc_caches_init();
buffer_init();
key_init();
diff --git a/kernel/fork.c b/kernel/fork.c
index c507e29bcb01..01038e6f51a8 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -253,7 +253,26 @@ EXPORT_SYMBOL_GPL(__put_task_struct);
void __init __weak arch_task_cache_init(void) { }
-void __init fork_init(unsigned long mempages)
+/*
+ * set_max_threads
+ */
+static void set_max_threads(void)
+{
+ /*
+ * The default maximum number of threads is set to a safe
+ * value: the thread structures can take up at most one
+ * eighth of the memory.
+ */
+ max_threads = totalram_pages / (8 * THREAD_SIZE / PAGE_SIZE);
+
+ /*
+ * we need to allow at least 20 threads to boot a system
+ */
+ if (max_threads < 20)
+ max_threads = 20;
+}
+
+void __init fork_init(void)
{
#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
#ifndef ARCH_MIN_TASKALIGN
@@ -268,18 +287,7 @@ void __init fork_init(unsigned long mempages)
/* do the arch specific task caches init */
arch_task_cache_init();
- /*
- * The default maximum number of threads is set to a safe
- * value: the thread structures can take up at most one
- * eighth of the memory.
- */
- max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE);
-
- /*
- * we need to allow at least 20 threads to boot a system
- */
- if (max_threads < 20)
- max_threads = 20;
+ set_max_threads();
init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;