The kernel currently uses an 8k stack, per task. Here is the
infrastructure needed to allow us to halve that.
D-4k-stack-2.5.50+bk-5.patch
make a config option to turn on 4k stacks. (there appears to
be a problem with this right now).
-- Dave Hansen haveblue@us.ibm.com
# This is a BitKeeper generated patch for the following project: # Project Name: Linux kernel tree # This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas: # ChangeSet 1.862 -> 1.864 # include/asm-i386/thread_info.h 1.13 -> 1.15 # arch/i386/Kconfig 1.15 -> 1.16 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 02/12/09 haveblue@elm3b96.(none) 1.863 # Merge elm3b96.(none):/work/dave/bk/linux-2.5-stack_size-config # into elm3b96.(none):/work/dave/bk/linux-2.5-4k_stack # -------------------------------------------- # 02/12/09 haveblue@elm3b96.(none) 1.864 # thread_info.h: # do sane overflow detection with 4k stack # -------------------------------------------- # diff -Nru a/arch/i386/Kconfig b/arch/i386/Kconfig --- a/arch/i386/Kconfig Mon Dec 9 13:33:26 2002 +++ b/arch/i386/Kconfig Mon Dec 9 13:33:26 2002 @@ -720,6 +720,16 @@ low memory. Setting this option will put user-space page table entries in high memory. +config 4K_STACK + bool "Use smaller 4k per-task stacks" + help + This option will shrink the kernel's per-task stack from 8k to + 4k. This will greatly increase your chance of overflowing it. + But, if you use the per-cpu interrupt stacks as well, your chances + go way down. Also try the CONFIG_X86_STACK_CHECK overflow + detection. It is much more reliable than the currently in-kernel + version. + config MATH_EMULATION bool "Math emulation" ---help--- diff -Nru a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h --- a/include/asm-i386/thread_info.h Mon Dec 9 13:33:26 2002 +++ b/include/asm-i386/thread_info.h Mon Dec 9 13:33:26 2002 @@ -61,10 +61,16 @@ * * preempt_count needs to be 1 initially, until the scheduler is functional. */ -#define THREAD_ORDER 1 +#ifdef CONFIG_4K_STACK +#define THREAD_ORDER 0 +#define STACK_WARN 0x200 +#define STACK_PANIC 0x100 +#else +#define THREAD_ORDER 1 +#define STACK_WARN ((THREAD_SIZE)>>1) +#define STACK_PANIC 0x100 +#endif #define INIT_THREAD_SIZE THREAD_SIZE -#define STACK_PANIC 0x200ul -#define STACK_WARN ((THREAD_SIZE)>>1) #ifndef __ASSEMBLY__
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This archive was generated by hypermail 2b29 : Sun Dec 15 2002 - 22:00:15 EST