Only allocate the FPU area when the application actually uses FPU, i.e., in the first lazy FPU trap. This could save memory for non-fpu using apps. Signed-off-by: Suresh Siddha Cc: Arjan van de Ven --- Index: linux-2.6-x86/arch/x86/kernel/i387.c =================================================================== --- linux-2.6-x86.orig/arch/x86/kernel/i387.c 2008-02-23 18:27:40.000000000 -0800 +++ linux-2.6-x86/arch/x86/kernel/i387.c 2008-02-23 18:27:41.000000000 -0800 @@ -9,7 +9,6 @@ #include #include #include -#include #include #include #include @@ -67,7 +66,6 @@ else math_cntxt_size = sizeof(struct i387_fsave_struct); #endif - init_task.thread.cntxt = alloc_bootmem(math_cntxt_size); } #ifdef CONFIG_X86_64 @@ -105,6 +103,9 @@ return; } + if (!tsk->thread.cntxt) + tsk->thread.cntxt = alloc_cntxt_struct(); + if (cpu_has_fxsr) { memset(FXSAVE(tsk), 0, math_cntxt_size); FXSAVE(tsk)->cwd = 0x37f; Index: linux-2.6-x86/arch/x86/kernel/process.c =================================================================== --- linux-2.6-x86.orig/arch/x86/kernel/process.c 2008-02-23 18:27:40.000000000 -0800 +++ linux-2.6-x86/arch/x86/kernel/process.c 2008-02-23 18:27:49.000000000 -0800 @@ -8,21 +8,25 @@ static struct kmem_cache *task_struct_cachep; static struct kmem_cache *task_cntxt_cachep; -struct task_struct * alloc_task_struct(void) +union thread_cntxt *alloc_cntxt_struct(void) +{ + return kmem_cache_alloc(task_cntxt_cachep, GFP_KERNEL); +} + +struct task_struct * alloc_task_struct(struct task_struct *src) { struct task_struct *tsk; tsk = kmem_cache_alloc(task_struct_cachep, GFP_KERNEL); - if (!tsk) - return NULL; - tsk->thread.cntxt = kmem_cache_alloc(task_cntxt_cachep, GFP_KERNEL); - if (!tsk->thread.cntxt) - goto error; - WARN_ON((unsigned long)tsk->thread.cntxt & 15); + if (tsk && src->thread.cntxt) { + tsk->thread.cntxt = alloc_cntxt_struct(); + if (!tsk->thread.cntxt) { + kmem_cache_free(task_struct_cachep, tsk); + return NULL; + } + WARN_ON((unsigned long)tsk->thread.cntxt & 15); + } else if (tsk) + tsk->thread.cntxt = NULL; return tsk; - -error: - kmem_cache_free(task_struct_cachep, tsk); - return NULL; } void memcpy_task_struct(struct task_struct *dst, struct task_struct *src) @@ -31,13 +35,21 @@ ptr = dst->thread.cntxt; *dst = *src; dst->thread.cntxt = ptr; - memcpy(dst->thread.cntxt, src->thread.cntxt, math_cntxt_size); + if (src->thread.cntxt) + memcpy(dst->thread.cntxt, src->thread.cntxt, math_cntxt_size); +} + +void free_cntxt_struct(struct task_struct *tsk) +{ + if (tsk->thread.cntxt) { + kmem_cache_free(task_cntxt_cachep, tsk->thread.cntxt); + tsk->thread.cntxt = NULL; + } } void free_task_struct(struct task_struct *tsk) { - kmem_cache_free(task_cntxt_cachep, tsk->thread.cntxt); - tsk->thread.cntxt=NULL; + free_cntxt_struct(tsk); kmem_cache_free(task_struct_cachep, tsk); } Index: linux-2.6-x86/include/asm-x86/i387.h =================================================================== --- linux-2.6-x86.orig/include/asm-x86/i387.h 2008-02-23 18:27:40.000000000 -0800 +++ linux-2.6-x86/include/asm-x86/i387.h 2008-02-23 18:27:41.000000000 -0800 @@ -25,6 +25,7 @@ extern asmlinkage void math_state_restore(void); extern void init_thread_context(void); extern unsigned int math_cntxt_size; +extern union thread_cntxt *alloc_cntxt_struct(void); extern user_regset_active_fn fpregs_active, xfpregs_active; extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get; Index: linux-2.6-x86/include/asm-x86/processor.h =================================================================== --- linux-2.6-x86.orig/include/asm-x86/processor.h 2008-02-23 18:27:40.000000000 -0800 +++ linux-2.6-x86/include/asm-x86/processor.h 2008-02-23 18:27:41.000000000 -0800 @@ -743,6 +743,8 @@ .io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 }, \ } +extern void free_cntxt_struct(struct task_struct *); + #define start_thread(regs, new_eip, new_esp) do { \ __asm__("movl %0,%%gs": :"r" (0)); \ regs->fs = 0; \ @@ -753,6 +755,7 @@ regs->cs = __USER_CS; \ regs->ip = new_eip; \ regs->sp = new_esp; \ + free_cntxt_struct(current); \ } while (0) Index: linux-2.6-x86/include/asm-x86/thread_info.h =================================================================== --- linux-2.6-x86.orig/include/asm-x86/thread_info.h 2008-02-23 18:27:40.000000000 -0800 +++ linux-2.6-x86/include/asm-x86/thread_info.h 2008-02-23 18:27:41.000000000 -0800 @@ -6,7 +6,7 @@ #ifndef __ASSEMBLY__ #define __HAVE_ARCH_TASK_STRUCT_ALLOCATOR -extern struct task_struct * alloc_task_struct(void); +extern struct task_struct * alloc_task_struct(struct task_struct *src); extern void free_task_struct(struct task_struct *tsk); extern void memcpy_task_struct(struct task_struct *dst, struct task_struct *src ); Index: linux-2.6-x86/kernel/fork.c =================================================================== --- linux-2.6-x86.orig/kernel/fork.c 2008-02-23 18:27:40.000000000 -0800 +++ linux-2.6-x86/kernel/fork.c 2008-02-23 18:27:41.000000000 -0800 @@ -85,7 +85,7 @@ } #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR -# define alloc_task_struct() kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) +# define alloc_task_struct(src) kmem_cache_alloc(task_struct_cachep, GFP_KERNEL) # define free_task_struct(tsk) kmem_cache_free(task_struct_cachep, (tsk)) # define memcpy_task_struct(dst, src) do { *dst = *src; } while (0) static struct kmem_cache *task_struct_cachep; @@ -174,7 +174,7 @@ prepare_to_copy(orig); - tsk = alloc_task_struct(); + tsk = alloc_task_struct(orig); if (!tsk) return NULL; -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/