Below is a patch against base 2.5.20 which makes the io port
bitmap in thread_struct a pointer to a bitmap that is only
allocated when the process calls ioperm. This results in 132
bytes being removed from struct task_struct.
-ben
-- "You will be reincarnated as a toad; and you will be much happier."
diff -urN v2.5.20/arch/i386/kernel/ioport.c iobitmap-2.5.20.diff/arch/i386/kernel/ioport.c --- v2.5.20/arch/i386/kernel/ioport.c Mon Jul 19 18:22:48 1999 +++ iobitmap-2.5.20.diff/arch/i386/kernel/ioport.c Thu Jun 6 00:54:22 2002 @@ -66,12 +66,15 @@ * IO bitmap up. ioperm() is much less timing critical than clone(), * this is why we delay this operation until now: */ - if (!t->ioperm) { + if (!t->ts_io_bitmap) { + unsigned long *bitmap = kmalloc((IO_BITMAP_SIZE+1)*4, GFP_KERNEL); + if (!bitmap) + return -ENOMEM; /* * just in case ... */ - memset(t->io_bitmap,0xff,(IO_BITMAP_SIZE+1)*4); - t->ioperm = 1; + memset(bitmap, 0xff, (IO_BITMAP_SIZE+1)*4); + t->ts_io_bitmap = bitmap; /* * this activates it in the TSS */ @@ -81,7 +84,7 @@ /* * do it in the per-thread copy and in the TSS ... */ - set_bitmap(t->io_bitmap, from, num, !turn_on); + set_bitmap(t->ts_io_bitmap, from, num, !turn_on); set_bitmap(tss->io_bitmap, from, num, !turn_on); return 0; diff -urN v2.5.20/arch/i386/kernel/process.c iobitmap-2.5.20.diff/arch/i386/kernel/process.c --- v2.5.20/arch/i386/kernel/process.c Thu Jun 6 00:35:52 2002 +++ iobitmap-2.5.20.diff/arch/i386/kernel/process.c Thu Jun 6 00:51:03 2002 @@ -685,8 +685,8 @@ loaddebug(next, 7); } - if (unlikely(prev->ioperm || next->ioperm)) { - if (next->ioperm) { + if (unlikely(prev->ts_io_bitmap || next->ts_io_bitmap)) { + if (next->ts_io_bitmap) { /* * 4 cachelines copy ... not good, but not that * bad either. Anyone got something better? @@ -695,7 +695,7 @@ * and playing VM tricks to switch the IO bitmap * is not really acceptable.] */ - memcpy(tss->io_bitmap, next->io_bitmap, + memcpy(tss->io_bitmap, next->ts_io_bitmap, IO_BITMAP_SIZE*sizeof(unsigned long)); tss->bitmap = IO_BITMAP_OFFSET; } else diff -urN v2.5.20/include/asm-alpha/thread_info.h iobitmap-2.5.20.diff/include/asm-alpha/thread_info.h --- v2.5.20/include/asm-alpha/thread_info.h Thu Jun 6 00:35:33 2002 +++ iobitmap-2.5.20.diff/include/asm-alpha/thread_info.h Thu Jun 6 01:01:05 2002 @@ -51,6 +51,7 @@ #define free_thread_info(ti) free_pages((unsigned long) (ti), 1) #define get_thread_info(ti) get_task_struct((ti)->task) #define put_thread_info(ti) put_task_struct((ti)->task) +#define arch_dispose_thread_struct(tsk) do{}while(0) #endif /* __ASSEMBLY__ */ diff -urN v2.5.20/include/asm-arm/thread_info.h iobitmap-2.5.20.diff/include/asm-arm/thread_info.h --- v2.5.20/include/asm-arm/thread_info.h Thu Jun 6 00:36:03 2002 +++ iobitmap-2.5.20.diff/include/asm-arm/thread_info.h Thu Jun 6 01:01:13 2002 @@ -82,6 +82,7 @@ extern struct thread_info *alloc_thread_info(void); extern void free_thread_info(struct thread_info *); +#define arch_dispose_thread_struct(tsk) do{}while(0) #define get_thread_info(ti) get_task_struct((ti)->task) #define put_thread_info(ti) put_task_struct((ti)->task) diff -urN v2.5.20/include/asm-i386/processor.h iobitmap-2.5.20.diff/include/asm-i386/processor.h --- v2.5.20/include/asm-i386/processor.h Thu Jun 6 00:35:53 2002 +++ iobitmap-2.5.20.diff/include/asm-i386/processor.h Thu Jun 6 00:50:06 2002 @@ -369,8 +369,7 @@ unsigned long screen_bitmap; unsigned long v86flags, v86mask, v86mode, saved_esp0; /* IO permissions */ - int ioperm; - unsigned long io_bitmap[IO_BITMAP_SIZE+1]; + unsigned long *ts_io_bitmap; }; #define INIT_THREAD { \ @@ -380,7 +379,7 @@ 0, 0, 0, \ { { 0, }, }, /* 387 state */ \ 0,0,0,0,0,0, \ - 0,{~0,} /* io permissions */ \ + 0,NULL, /* io permissions */ \ } #define INIT_TSS { \ diff -urN v2.5.20/include/asm-i386/thread_info.h iobitmap-2.5.20.diff/include/asm-i386/thread_info.h --- v2.5.20/include/asm-i386/thread_info.h Thu Jun 6 00:35:32 2002 +++ iobitmap-2.5.20.diff/include/asm-i386/thread_info.h Thu Jun 6 01:00:13 2002 @@ -79,6 +79,7 @@ #define free_thread_info(ti) free_pages((unsigned long) (ti), 1) #define get_thread_info(ti) get_task_struct((ti)->task) #define put_thread_info(ti) put_task_struct((ti)->task) +#define arch_dispose_thread_struct(tsk) kfree((tsk)->thread.ts_io_bitmap) #else /* !__ASSEMBLY__ */ diff -urN v2.5.20/include/asm-ia64/thread_info.h iobitmap-2.5.20.diff/include/asm-ia64/thread_info.h --- v2.5.20/include/asm-ia64/thread_info.h Thu Jun 6 00:35:33 2002 +++ iobitmap-2.5.20.diff/include/asm-ia64/thread_info.h Thu Jun 6 01:01:39 2002 @@ -46,6 +46,7 @@ /* how to get the thread information struct from C */ #define current_thread_info() ((struct thread_info *) ((char *) current + IA64_TASK_SIZE)) +#define arch_dispose_thread_struct(tsk) do{}while(0) #endif /* !__ASSEMBLY */ diff -urN v2.5.20/include/asm-ppc/thread_info.h iobitmap-2.5.20.diff/include/asm-ppc/thread_info.h --- v2.5.20/include/asm-ppc/thread_info.h Thu Jun 6 00:35:49 2002 +++ iobitmap-2.5.20.diff/include/asm-ppc/thread_info.h Thu Jun 6 01:01:46 2002 @@ -55,6 +55,7 @@ #define free_thread_info(ti) free_pages((unsigned long) (ti), 1) #define get_thread_info(ti) get_task_struct((ti)->task) #define put_thread_info(ti) put_task_struct((ti)->task) +#define arch_dispose_thread_struct(tsk) do{}while(0) #endif /* __ASSEMBLY__ */ /* diff -urN v2.5.20/include/asm-ppc64/thread_info.h iobitmap-2.5.20.diff/include/asm-ppc64/thread_info.h --- v2.5.20/include/asm-ppc64/thread_info.h Thu Jun 6 00:36:03 2002 +++ iobitmap-2.5.20.diff/include/asm-ppc64/thread_info.h Thu Jun 6 01:01:51 2002 @@ -50,6 +50,7 @@ #define free_thread_info(ti) free_pages((unsigned long) (ti), THREAD_ORDER) #define get_thread_info(ti) get_task_struct((ti)->task) #define put_thread_info(ti) put_task_struct((ti)->task) +#define arch_dispose_thread_struct(tsk) do{}while(0) #if THREAD_SIZE != (4*PAGE_SIZE) #error update vmlinux.lds and current_thread_info to match diff -urN v2.5.20/include/asm-sparc64/thread_info.h iobitmap-2.5.20.diff/include/asm-sparc64/thread_info.h --- v2.5.20/include/asm-sparc64/thread_info.h Thu Jun 6 00:35:49 2002 +++ iobitmap-2.5.20.diff/include/asm-sparc64/thread_info.h Thu Jun 6 01:02:03 2002 @@ -130,6 +130,7 @@ /* how to get the thread information struct from C */ register struct thread_info *current_thread_info_reg asm("g6"); #define current_thread_info() (current_thread_info_reg) +#define arch_dispose_thread_struct(tsk) do{}while(0) /* thread information allocation */ #if PAGE_SHIFT == 13 diff -urN v2.5.20/include/asm-x86_64/thread_info.h iobitmap-2.5.20.diff/include/asm-x86_64/thread_info.h --- v2.5.20/include/asm-x86_64/thread_info.h Thu Jun 6 00:35:33 2002 +++ iobitmap-2.5.20.diff/include/asm-x86_64/thread_info.h Thu Jun 6 01:02:08 2002 @@ -71,6 +71,7 @@ #define free_thread_info(ti) free_pages((unsigned long) (ti), 1) #define get_thread_info(ti) get_task_struct((ti)->task) #define put_thread_info(ti) put_task_struct((ti)->task) +#define arch_dispose_thread_struct(tsk) do{}while(0) #else /* !__ASSEMBLY__ */ diff -urN v2.5.20/kernel/fork.c iobitmap-2.5.20.diff/kernel/fork.c --- v2.5.20/kernel/fork.c Thu Jun 6 00:35:50 2002 +++ iobitmap-2.5.20.diff/kernel/fork.c Thu Jun 6 01:00:10 2002 @@ -123,6 +123,7 @@ void __put_task_struct(struct task_struct *tsk) { + arch_dispose_thread_struct(tsk); free_thread_info(tsk->thread_info); kmem_cache_free(task_struct_cachep,tsk); } - 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/