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authorIngo Molnar <mingo@kernel.org>2015-07-17 12:28:12 +0200
committerIngo Molnar <mingo@kernel.org>2015-07-18 03:42:51 +0200
commit5aaeb5c01c5b6c0be7b7aadbf3ace9f3a4458c3d (patch)
tree8cf45cdd6647d1067d94aaad64598a7728f15d6b /kernel/fork.c
parent0c8c0f03e3a292e031596484275c14cf39c0ab7a (diff)
x86/fpu, sched: Introduce CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT and use it on x86
Don't burden architectures without dynamic task_struct sizing with the overhead of dynamic sizing. Also optimize the x86 code a bit by caching task_struct_size. Acked-and-Tested-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1437128892-9831-3-git-send-email-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c11
1 files changed, 5 insertions, 6 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 431b67a6098c..dbd9b8d7b7cc 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -287,21 +287,20 @@ static void set_max_threads(unsigned int max_threads_suggested)
max_threads = clamp_t(u64, threads, MIN_THREADS, MAX_THREADS);
}
-int __weak arch_task_struct_size(void)
-{
- return sizeof(struct task_struct);
-}
+#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
+/* Initialized by the architecture: */
+int arch_task_struct_size __read_mostly;
+#endif
void __init fork_init(void)
{
- int task_struct_size = arch_task_struct_size();
#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
#ifndef ARCH_MIN_TASKALIGN
#define ARCH_MIN_TASKALIGN L1_CACHE_BYTES
#endif
/* create a slab on which task_structs can be allocated */
task_struct_cachep =
- kmem_cache_create("task_struct", task_struct_size,
+ kmem_cache_create("task_struct", arch_task_struct_size,
ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL);
#endif