linux/arch/x86/kernel/process.c

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/sched.h>

static struct kmem_cache *task_xstate_cachep;

int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
	*dst = *src;
	dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
	if (!dst->thread.xstate)
		return -ENOMEM;
	WARN_ON((unsigned long)dst->thread.xstate & 15);
	memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
	return 0;
}

void free_thread_info(struct thread_info *ti)
{
	kmem_cache_free(task_xstate_cachep, ti->task->thread.xstate);
	ti->task->thread.xstate = NULL;

	free_pages((unsigned long)(ti), get_order(THREAD_SIZE));
}

void arch_task_cache_init(void)
{
        task_xstate_cachep =
        	kmem_cache_create("task_xstate", xstate_size,
				  __alignof__(union thread_xstate),
				  SLAB_PANIC, NULL);
}