diff options
author | Suresh Siddha <suresh.b.siddha@intel.com> | 2008-03-10 15:28:04 -0700 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-04-19 19:19:55 +0200 |
commit | 61c4628b538608c1a85211ed8438136adfeb9a95 (patch) | |
tree | 290a695299a363153bc692e6d705ac680d64359e /kernel | |
parent | fa5c4639419668cbb18ca3d20c1253559a3b43ae (diff) |
x86, fpu: split FPU state from task struct - v5
Split the FPU save area from the task struct. This allows easy migration
of FPU context, and it's generally cleaner. It also allows the following
two optimizations:
1) only allocate when the application actually uses FPU, so in the first
lazy FPU trap. This could save memory for non-fpu using apps. Next patch
does this lazy allocation.
2) allocate the right size for the actual cpu rather than 512 bytes always.
Patches enabling xsave/xrstor support (coming shortly) will take advantage
of this.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/fork.c | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 9c042f90157..44a18192c42 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -132,6 +132,10 @@ void __put_task_struct(struct task_struct *tsk) free_task(tsk); } +void __attribute__((weak)) arch_task_cache_init(void) +{ +} + void __init fork_init(unsigned long mempages) { #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR @@ -144,6 +148,9 @@ void __init fork_init(unsigned long mempages) ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL); #endif + /* 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 half @@ -163,6 +170,13 @@ void __init fork_init(unsigned long mempages) init_task.signal->rlim[RLIMIT_NPROC]; } +int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst, + struct task_struct *src) +{ + *dst = *src; + return 0; +} + static struct task_struct *dup_task_struct(struct task_struct *orig) { struct task_struct *tsk; @@ -181,15 +195,15 @@ static struct task_struct *dup_task_struct(struct task_struct *orig) return NULL; } - *tsk = *orig; + err = arch_dup_task_struct(tsk, orig); + if (err) + goto out; + tsk->stack = ti; err = prop_local_init_single(&tsk->dirties); - if (err) { - free_thread_info(ti); - free_task_struct(tsk); - return NULL; - } + if (err) + goto out; setup_thread_stack(tsk, orig); @@ -205,6 +219,11 @@ static struct task_struct *dup_task_struct(struct task_struct *orig) #endif tsk->splice_pipe = NULL; return tsk; + +out: + free_thread_info(ti); + free_task_struct(tsk); + return NULL; } #ifdef CONFIG_MMU |