I've resynced Ben's patch against 2.5.40. However, I'm getting some
strange failures. The patch is good enough to pass LTP, but
consistently freezes when I run tcpdump on it.
Although I don't have CONFIG_PREEMPT on, I have the feeling that I
need to disable preemption in common_interrupt() like it was before.
Any insights would be appreciated.
part of Ben LaHaise's original message:
> Below is a patch against 2.5.20 that implements 4KB stacks for
> tasks, plus a seperate 4KB irq stack for use by interrupts. There
> are a couple of reasons for doing this: 4KB stacks put less pressure
> on the VM subsystem, reduces the overall memory usage for systems
> with large numbers of tasks, and increases the reliability of the
> system when under heavy irq load by provide a fixed stack size for
> interrupt handlers that other kernel code will not eat into.
>
> The interrupt stacks are stackable, so we could use multiple
> 4KB irq stacks. The thread_info structure is included in each
> interrupt stack, and has the current pointer copied into it upon
> entry.
-- Dave Hansen haveblue@us.ibm.com
--------------090501030701050105060509 Content-Type: text/plain; name="4k+interrupt-stack-2.5.40-1.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="4k+interrupt-stack-2.5.40-1.patch"
diff -ur linux-2.5.40-clean/arch/i386/config.in linux-2.5.40/arch/i386/config.in --- linux-2.5.40-clean/arch/i386/config.in 2002-10-02 12:59:09.000000000 -0700 +++ linux-2.5.40/arch/i386/config.in 2002-10-02 12:59:55.000000000 -0700 @@ -35,6 +35,7 @@ # # Define implied options from the CPU selection here # +define_bool CONFIG_X86_HAVE_CMOV n if [ "$CONFIG_M386" = "y" ]; then define_bool CONFIG_X86_CMPXCHG n @@ -91,18 +92,21 @@ define_bool CONFIG_X86_GOOD_APIC y define_bool CONFIG_X86_USE_PPRO_CHECKSUM y define_bool CONFIG_X86_PPRO_FENCE y + define_bool CONFIG_X86_HAVE_CMOV y fi if [ "$CONFIG_MPENTIUMIII" = "y" ]; then define_int CONFIG_X86_L1_CACHE_SHIFT 5 define_bool CONFIG_X86_TSC y define_bool CONFIG_X86_GOOD_APIC y define_bool CONFIG_X86_USE_PPRO_CHECKSUM y + define_bool CONFIG_X86_HAVE_CMOV y fi if [ "$CONFIG_MPENTIUM4" = "y" ]; then define_int CONFIG_X86_L1_CACHE_SHIFT 7 define_bool CONFIG_X86_TSC y define_bool CONFIG_X86_GOOD_APIC y define_bool CONFIG_X86_USE_PPRO_CHECKSUM y + define_bool CONFIG_X86_HAVE_CMOV y fi if [ "$CONFIG_MK6" = "y" ]; then define_int CONFIG_X86_L1_CACHE_SHIFT 5 @@ -116,6 +120,7 @@ define_bool CONFIG_X86_GOOD_APIC y define_bool CONFIG_X86_USE_3DNOW y define_bool CONFIG_X86_USE_PPRO_CHECKSUM y + define_bool CONFIG_X86_HAVE_CMOV y fi if [ "$CONFIG_MELAN" = "y" ]; then define_int CONFIG_X86_L1_CACHE_SHIFT 4 @@ -132,6 +137,7 @@ if [ "$CONFIG_MCRUSOE" = "y" ]; then define_int CONFIG_X86_L1_CACHE_SHIFT 5 define_bool CONFIG_X86_TSC y + define_bool CONFIG_X86_HAVE_CMOV y fi if [ "$CONFIG_MWINCHIPC6" = "y" ]; then define_int CONFIG_X86_L1_CACHE_SHIFT 5 diff -ur linux-2.5.40-clean/arch/i386/kernel/entry.S linux-2.5.40/arch/i386/kernel/entry.S --- linux-2.5.40-clean/arch/i386/kernel/entry.S 2002-10-02 12:59:09.000000000 -0700 +++ linux-2.5.40/arch/i386/kernel/entry.S 2002-10-02 13:00:09.000000000 -0700 @@ -136,7 +136,7 @@ movl %ecx,CS(%esp) # movl %esp, %ebx pushl %ebx - andl $-8192, %ebx # GET_THREAD_INFO + GET_THREAD_INFO_WITH_ESP(%ebx) movl TI_EXEC_DOMAIN(%ebx), %edx # Get the execution domain movl 4(%edx), %edx # Get the lcall7 handler for the domain pushl $0x7 @@ -158,7 +158,7 @@ movl %ecx,CS(%esp) # movl %esp, %ebx pushl %ebx - andl $-8192, %ebx # GET_THREAD_INFO + GET_THREAD_INFO_WITH_ESP(%ebx) movl TI_EXEC_DOMAIN(%ebx), %edx # Get the execution domain movl 4(%edx), %edx # Get the lcall7 handler for the domain pushl $0x27 @@ -334,7 +334,30 @@ ALIGN common_interrupt: SAVE_ALL + GET_THREAD_INFO(%ebx) + + movl TI_IRQ_STACK(%ebx),%ecx + movl TI_TASK(%ebx),%edx + movl %esp,%eax + leal (THREAD_SIZE-4)(%ecx),%ebx + testl %ecx,%ecx # is there a valid irq_stack? + # switch to the irq stack +#ifdef CONFIG_X86_HAVE_CMOV + cmovnz %ebx,%esp +#warning using cmov +#else +#warning cannot use cmov + jnz 1f + mov %ebx,%esp +1: +#endif + + # update the task pointer in the irq stack + GET_THREAD_INFO(%ebx) + movl %edx,TI_TASK(%ebx) + call do_IRQ + movl %eax,%esp # potentially restore non-irq stack jmp ret_from_intr #define BUILD_INTERRUPT(name, nr) \ diff -ur linux-2.5.40-clean/arch/i386/kernel/head.S linux-2.5.40/arch/i386/kernel/head.S --- linux-2.5.40-clean/arch/i386/kernel/head.S 2002-10-02 12:59:09.000000000 -0700 +++ linux-2.5.40/arch/i386/kernel/head.S 2002-10-02 12:59:55.000000000 -0700 @@ -15,6 +15,7 @@ #include <asm/page.h> #include <asm/pgtable.h> #include <asm/desc.h> +#include <asm/thread_info.h> #define OLD_CL_MAGIC_ADDR 0x90020 #define OLD_CL_MAGIC 0xA33F @@ -305,7 +306,7 @@ ret ENTRY(stack_start) - .long init_thread_union+8192 + .long init_thread_union+THREAD_SIZE .long __KERNEL_DS /* This is the default interrupt "handler" :-) */ diff -ur linux-2.5.40-clean/arch/i386/kernel/init_task.c linux-2.5.40/arch/i386/kernel/init_task.c --- linux-2.5.40-clean/arch/i386/kernel/init_task.c 2002-10-02 12:59:09.000000000 -0700 +++ linux-2.5.40/arch/i386/kernel/init_task.c 2002-10-02 12:59:55.000000000 -0700 @@ -13,6 +13,9 @@ static struct signal_struct init_signals = INIT_SIGNALS(init_signals); struct mm_struct init_mm = INIT_MM(init_mm); +union thread_union init_irq_union + __attribute__((__section__(".data.init_task"))); + /* * Initial thread structure. * @@ -22,7 +25,15 @@ */ union thread_union init_thread_union __attribute__((__section__(".data.init_task"))) = - { INIT_THREAD_INFO(init_task) }; + { { + task: &init_task, + exec_domain: &default_exec_domain, + flags: 0, + cpu: 0, + addr_limit: KERNEL_DS, + irq_stack: &init_irq_union, + } }; + /* * Initial task structure. diff -ur linux-2.5.40-clean/arch/i386/kernel/irq.c linux-2.5.40/arch/i386/kernel/irq.c --- linux-2.5.40-clean/arch/i386/kernel/irq.c 2002-10-02 12:59:09.000000000 -0700 +++ linux-2.5.40/arch/i386/kernel/irq.c 2002-10-02 12:59:55.000000000 -0700 @@ -311,7 +311,8 @@ * SMP cross-CPU interrupts have their own specific * handlers). */ -asmlinkage unsigned int do_IRQ(struct pt_regs regs) +struct pt_regs *do_IRQ(struct pt_regs *regs) __attribute__((regparm(1))); +struct pt_regs *do_IRQ(struct pt_regs *regs) { /* * We ack quickly, we don't want the irq controller @@ -323,7 +324,7 @@ * 0 return value means that this irq is already being * handled by some other CPU. (or is disabled) */ - int irq = regs.orig_eax & 0xff; /* high bits used in ret_from_ code */ + int irq = regs->orig_eax & 0xff; /* high bits used in ret_from_ code */ int cpu = smp_processor_id(); irq_desc_t *desc = irq_desc + irq; struct irqaction * action; @@ -373,7 +374,7 @@ */ for (;;) { spin_unlock(&desc->lock); - handle_IRQ_event(irq, ®s, action); + handle_IRQ_event(irq, regs, action); spin_lock(&desc->lock); if (likely(!(desc->status & IRQ_PENDING))) @@ -392,7 +393,7 @@ irq_exit(); - return 1; + return regs; } /** diff -ur linux-2.5.40-clean/arch/i386/kernel/process.c linux-2.5.40/arch/i386/kernel/process.c --- linux-2.5.40-clean/arch/i386/kernel/process.c 2002-10-02 12:59:09.000000000 -0700 +++ linux-2.5.40/arch/i386/kernel/process.c 2002-10-02 12:59:55.000000000 -0700 @@ -413,6 +413,7 @@ /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ + next_p->thread_info->irq_stack = prev_p->thread_info->irq_stack; unlazy_fpu(prev_p); /* diff -ur linux-2.5.40-clean/arch/i386/kernel/smpboot.c linux-2.5.40/arch/i386/kernel/smpboot.c --- linux-2.5.40-clean/arch/i386/kernel/smpboot.c 2002-10-02 12:59:09.000000000 -0700 +++ linux-2.5.40/arch/i386/kernel/smpboot.c 2002-10-02 12:59:55.000000000 -0700 @@ -69,6 +69,10 @@ /* Per CPU bogomips and other parameters */ struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned; +extern union thread_union init_irq_union; +union thread_union *irq_stacks[NR_CPUS] __cacheline_aligned = + { &init_irq_union, }; + /* Set when the idlers are all forked */ int smp_threads_ready; @@ -763,6 +767,27 @@ return (send_status | accept_status); } +static void __init setup_irq_stack(struct task_struct *p, int cpu) +{ + unsigned long stk; + + stk = __get_free_pages(GFP_KERNEL, THREAD_ORDER); + if (!stk) + panic("I can't seem to allocate my irq stack. Oh well, giving up."); + + irq_stacks[cpu] = (void *)stk; + memset(irq_stacks[cpu], 0, THREAD_SIZE); + irq_stacks[cpu]->thread_info.cpu = cpu; + irq_stacks[cpu]->thread_info.preempt_count = 1; + /* interrupts are not preemptable */ + p->thread_info->irq_stack = irq_stacks[cpu]; + + /* If we want to make the irq stack more than one unit + * deep, we can chain then off of the irq_stack pointer + * here. + */ +} + extern unsigned long cpu_initialized; static void __init do_boot_cpu (int apicid) @@ -786,6 +811,8 @@ if (IS_ERR(idle)) panic("failed fork for CPU %d", cpu); + setup_irq_stack(idle, cpu); + /* * We remove it from the pidhash and the runqueue * once we got the process: @@ -803,7 +830,7 @@ /* So we see what's up */ printk("Booting processor %d/%d eip %lx\n", cpu, apicid, start_eip); - stack_start.esp = (void *) (1024 + PAGE_SIZE + (char *)idle->thread_info); + stack_start.esp = (void *) (THREAD_SIZE + (char *)idle->thread_info); /* * This grunge runs the startup process for diff -ur linux-2.5.40-clean/include/asm-i386/page.h linux-2.5.40/include/asm-i386/page.h --- linux-2.5.40-clean/include/asm-i386/page.h 2002-10-02 12:59:03.000000000 -0700 +++ linux-2.5.40/include/asm-i386/page.h 2002-10-02 12:59:55.000000000 -0700 @@ -3,7 +3,11 @@ /* PAGE_SHIFT determines the page size */ #define PAGE_SHIFT 12 +#ifndef __ASSEMBLY__ #define PAGE_SIZE (1UL << PAGE_SHIFT) +#else +#define PAGE_SIZE (1 << PAGE_SHIFT) +#endif #define PAGE_MASK (~(PAGE_SIZE-1)) #define LARGE_PAGE_MASK (~(LARGE_PAGE_SIZE-1)) diff -ur linux-2.5.40-clean/include/asm-i386/thread_info.h linux-2.5.40/include/asm-i386/thread_info.h --- linux-2.5.40-clean/include/asm-i386/thread_info.h 2002-10-02 12:59:03.000000000 -0700 +++ linux-2.5.40/include/asm-i386/thread_info.h 2002-10-02 12:59:55.000000000 -0700 @@ -9,6 +9,7 @@ #ifdef __KERNEL__ +#include <asm/page.h> #ifndef __ASSEMBLY__ #include <asm/processor.h> #endif @@ -28,9 +29,11 @@ __s32 preempt_count; /* 0 => preemptable, <0 => BUG */ mm_segment_t addr_limit; /* thread address space: + 0 for interrupts: illegal 0-0xBFFFFFFF for user-thead 0-0xFFFFFFFF for kernel-thread */ + struct thread_info *irq_stack; /* pointer to cpu irq stack */ __u8 supervisor_stack[0]; }; @@ -44,6 +47,7 @@ #define TI_CPU 0x0000000C #define TI_PRE_COUNT 0x00000010 #define TI_ADDR_LIMIT 0x00000014 +#define TI_IRQ_STACK 0x00000018 #endif @@ -54,42 +58,40 @@ * * preempt_count needs to be 1 initially, until the scheduler is functional. */ +#define THREAD_ORDER 0 + #ifndef __ASSEMBLY__ -#define INIT_THREAD_INFO(tsk) \ -{ \ - .task = &tsk, \ - .exec_domain = &default_exec_domain, \ - .flags = 0, \ - .cpu = 0, \ - .preempt_count = 1, \ - .addr_limit = KERNEL_DS, \ -} - #define init_thread_info (init_thread_union.thread_info) #define init_stack (init_thread_union.stack) +/* thread information allocation */ +#define THREAD_SIZE (PAGE_SIZE << THREAD_ORDER) +#define alloc_thread_info() ((struct thread_info *) __get_free_pages(GFP_KERNEL,THREAD_ORDER)) +#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) + /* how to get the thread information struct from C */ static inline struct thread_info *current_thread_info(void) { struct thread_info *ti; - __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~8191UL)); + __asm__("andl %%esp,%0; ":"=r" (ti) : "0" (~(THREAD_SIZE - 1))); return ti; } -/* thread information allocation */ -#define THREAD_SIZE (2*PAGE_SIZE) -#define alloc_thread_info() ((struct thread_info *) __get_free_pages(GFP_KERNEL,1)) -#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) - #else /* !__ASSEMBLY__ */ +#define THREAD_SIZE (PAGE_SIZE << THREAD_ORDER) + /* how to get the thread information struct from ASM */ #define GET_THREAD_INFO(reg) \ - movl $-8192, reg; \ + movl $-THREAD_SIZE, reg; \ andl %esp, reg +/* use this one if reg already contains %esp */ +#define GET_THREAD_INFO_WITH_ESP(reg) \ + andl $-THREAD_SIZE, reg + #endif /*
--------------090501030701050105060509--
- 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/