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x86, fpu: split FPU state from task struct - v5

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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>
This commit is contained in:
Suresh Siddha
2008-03-10 15:28:04 -07:00
committed by Ingo Molnar
parent fa5c463941
commit 61c4628b53
16 changed files with 161 additions and 90 deletions
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31
kernel/fork.c
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@@ -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