From 13a0c3c269b223f60abfac8a9811d77111a8b4ba Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Fri, 26 Dec 2008 02:05:47 -0800 Subject: sparseirq: work around compiler optimizing away __weak functions Impact: fix panic on null pointer with sparseirq Some GCC versions seem to inline the weak global function, when that function is empty. Work it around, by making the functions return a (dummy) integer. Signed-off-by: Yinghai Signed-off-by: Ingo Molnar --- init/main.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index c1f999a3cf31..c314aa15370e 100644 --- a/init/main.c +++ b/init/main.c @@ -539,13 +539,14 @@ void __init __weak thread_info_cache_init(void) { } -void __init __weak arch_early_irq_init(void) +int __init __weak arch_early_irq_init(void) { + return 0; } -void __init __weak early_irq_init(void) +int __init __weak early_irq_init(void) { - arch_early_irq_init(); + return arch_early_irq_init(); } asmlinkage void __init start_kernel(void) -- cgit v1.2.3 From 43a256322ac1fc105c181b3cade3b9bfc0b63ca1 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Sun, 28 Dec 2008 16:01:13 -0800 Subject: sparseirq: move __weak symbols into separate compilation unit GCC has a bug with __weak alias functions: if the functions are in the same compilation unit as their call site, GCC can decide to inline them - and thus rob the linker of the opportunity to override the weak alias with the real thing. So move all the IRQ handling related __weak symbols to kernel/irq/chip.c. Signed-off-by: Yinghai Lu Signed-off-by: Ingo Molnar --- include/linux/interrupt.h | 6 ++++++ include/linux/irq.h | 3 --- init/main.c | 10 ---------- kernel/irq/manage.c | 9 --------- kernel/softirq.c | 20 ++++++++++++++++++++ 5 files changed, 26 insertions(+), 22 deletions(-) (limited to 'init/main.c') diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index 777f89e00b4a..d9a370325ae2 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -467,4 +467,10 @@ static inline void init_irq_proc(void) int show_interrupts(struct seq_file *p, void *v); +struct irq_desc; + +extern int early_irq_init(void); +extern int arch_early_irq_init(void); +extern int arch_init_chip_data(struct irq_desc *desc, int cpu); + #endif diff --git a/include/linux/irq.h b/include/linux/irq.h index 0e40af4bac40..d64a6d49bdef 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -193,9 +193,6 @@ struct irq_desc { const char *name; } ____cacheline_internodealigned_in_smp; -extern int early_irq_init(void); -extern int arch_early_irq_init(void); -extern int arch_init_chip_data(struct irq_desc *desc, int cpu); extern void arch_init_copy_chip_data(struct irq_desc *old_desc, struct irq_desc *desc, int cpu); extern void arch_free_chip_data(struct irq_desc *old_desc, struct irq_desc *desc); diff --git a/init/main.c b/init/main.c index c314aa15370e..2c183abbf61c 100644 --- a/init/main.c +++ b/init/main.c @@ -539,16 +539,6 @@ void __init __weak thread_info_cache_init(void) { } -int __init __weak arch_early_irq_init(void) -{ - return 0; -} - -int __init __weak early_irq_init(void) -{ - return arch_early_irq_init(); -} - asmlinkage void __init start_kernel(void) { char * command_line; diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index c2741b02ad38..46953a06f4a8 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -261,15 +261,6 @@ void enable_irq(unsigned int irq) } EXPORT_SYMBOL(enable_irq); -/* - * [ Not in kernel/irq/handle.c, so that GCC does not - * inline the __weak alias: ] - */ -int __weak arch_init_chip_data(struct irq_desc *desc, int cpu) -{ - return 0; -} - static int set_irq_wake_real(unsigned int irq, unsigned int on) { struct irq_desc *desc = irq_to_desc(irq); diff --git a/kernel/softirq.c b/kernel/softirq.c index e7c69a720d69..daf46358d2dd 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -797,3 +797,23 @@ int on_each_cpu(void (*func) (void *info), void *info, int wait) } EXPORT_SYMBOL(on_each_cpu); #endif + +/* + * [ These __weak aliases are kept in a separate compilation unit, so that + * GCC does not inline them incorrectly. ] + */ + +int __init __weak early_irq_init(void) +{ + return 0; +} + +int __init __weak arch_early_irq_init(void) +{ + return 0; +} + +int __weak arch_init_chip_data(struct irq_desc *desc, int cpu) +{ + return 0; +} -- cgit v1.2.3 From 915441b601e6662e79f6c958e7be307967a96977 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 1 Jan 2009 10:12:15 +1030 Subject: cpumask: Use accessors code in core Impact: use new API cpu_*_map are going away in favour of cpu_*_mask, but const pointers. So we have accessors where we really do want to frob them. Archs will also need the (trivial) conversion before we can finally remove cpu_*_map. Signed-off-by: Rusty Russell Signed-off-by: Mike Travis --- init/main.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index 2a7ce0f8e453..84d3732c0ce5 100644 --- a/init/main.c +++ b/init/main.c @@ -527,9 +527,9 @@ static void __init boot_cpu_init(void) { int cpu = smp_processor_id(); /* Mark the boot cpu "present", "online" etc for SMP and UP case */ - cpu_set(cpu, cpu_online_map); - cpu_set(cpu, cpu_present_map); - cpu_set(cpu, cpu_possible_map); + set_cpu_online(cpu, true); + set_cpu_present(cpu, true); + set_cpu_possible(cpu, true); } void __init __weak smp_setup_processor_id(void) -- cgit v1.2.3 From e0c0ba736547e81c4f986ce192307c549d214167 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 1 Jan 2009 10:12:19 +1030 Subject: cpumask: Use find_last_bit() Impact: cleanup There's one obvious place to use it: to find the highest possible cpu. Signed-off-by: Rusty Russell --- init/main.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index 84d3732c0ce5..546ebd2f44ba 100644 --- a/init/main.c +++ b/init/main.c @@ -380,12 +380,7 @@ EXPORT_SYMBOL(nr_cpu_ids); /* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */ static void __init setup_nr_cpu_ids(void) { - int cpu, highest_cpu = 0; - - for_each_possible_cpu(cpu) - highest_cpu = cpu; - - nr_cpu_ids = highest_cpu + 1; + nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1; } #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA -- cgit v1.2.3 From 609e5b71d0eca163df017ecfcf917b149875e744 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 2 Jan 2009 16:16:16 +0100 Subject: kbuild: Remove gcc 4.1.0 quirk from init/main.c Impact: cleanup We now have a cleaner check for gcc 4.1.0/4.1.1 trouble in include/linux/compiler-gcc4.h, so remove the 4.1.0 quirk from init/main.c. Reported-by: Bartlomiej Zolnierkiewicz Signed-off-by: Ingo Molnar Acked-by: Sam Ravnborg Signed-off-by: Linus Torvalds --- init/main.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index f5e64f20d2b0..ad8f9f53f8d1 100644 --- a/init/main.c +++ b/init/main.c @@ -75,15 +75,6 @@ #include #endif -/* - * This is one of the first .c files built. Error out early if we have compiler - * trouble. - */ - -#if __GNUC__ == 4 && __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ == 0 -#warning gcc-4.1.0 is known to miscompile the kernel. A different compiler version is recommended. -#endif - static int kernel_init(void *); extern void init_IRQ(void); -- cgit v1.2.3 From 24d431d06aeeda2b12cc925c6e1693c45ae5088b Mon Sep 17 00:00:00 2001 From: Ron Lee Date: Thu, 27 Nov 2008 02:31:57 +1030 Subject: trivial: add missing printk loglevel in start_kernel Add missing printk loglevel in start_kernel Signed-off-by: Ron Lee Signed-off-by: Jiri Kosina --- init/main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index cd168ebc5924..798fe450e708 100644 --- a/init/main.c +++ b/init/main.c @@ -602,7 +602,8 @@ asmlinkage void __init start_kernel(void) sched_clock_init(); profile_init(); if (!irqs_disabled()) - printk("start_kernel(): bug: interrupts were enabled early\n"); + printk(KERN_CRIT "start_kernel(): bug: interrupts were " + "enabled early\n"); early_boot_irqs_on(); local_irq_enable(); -- cgit v1.2.3 From f99ebf0a86de13f77bc4ee349de96db9f2f67f2e Mon Sep 17 00:00:00 2001 From: Rakib Mullick Date: Tue, 6 Jan 2009 14:40:38 -0800 Subject: init: properly placing noinline keyword checkpatch warns about 'static void noinline'. It wants `static noinline void'. Both are permissible, but the kernel consistently uses `static inline' and `static noinline', and consistency is good. Hence let's keep the checkpatch warning and fix up this code site. [akpm@linux-foundation.org: rewrote changelog] Signed-off-by: Md.Rakib H. Mullick Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/main.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index cd168ebc5924..90926dadc20d 100644 --- a/init/main.c +++ b/init/main.c @@ -447,7 +447,7 @@ static void __init setup_command_line(char *command_line) * gcc-3.4 accidentally inlines this function, so use noinline. */ -static void noinline __init_refok rest_init(void) +static noinline void __init_refok rest_init(void) __releases(kernel_lock) { int pid; @@ -786,7 +786,7 @@ static void run_init_process(char *init_filename) /* This is a non __init function. Force it to be noinline otherwise gcc * makes it inline to init() and it becomes part of init.text section */ -static int noinline init_post(void) +static noinline int init_post(void) { free_initmem(); unlock_kernel(); -- cgit v1.2.3 From f1883f86dea84fe47a71a39fc1afccc005915ed8 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Tue, 6 Jan 2009 14:40:45 -0800 Subject: Remove remaining unwinder code Signed-off-by: Alexey Dobriyan Cc: Gabor Gombas Cc: Jan Beulich Cc: Andi Kleen Cc: Ingo Molnar , Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/include/asm/unwind.h | 13 --------- arch/x86/kernel/traps.c | 2 -- include/linux/module.h | 3 -- include/linux/unwind.h | 68 ------------------------------------------- init/main.c | 3 -- kernel/module.c | 15 ---------- lib/fault-inject.c | 1 - 7 files changed, 105 deletions(-) delete mode 100644 arch/x86/include/asm/unwind.h delete mode 100644 include/linux/unwind.h (limited to 'init/main.c') diff --git a/arch/x86/include/asm/unwind.h b/arch/x86/include/asm/unwind.h deleted file mode 100644 index 8b064bd9c553..000000000000 --- a/arch/x86/include/asm/unwind.h +++ /dev/null @@ -1,13 +0,0 @@ -#ifndef _ASM_X86_UNWIND_H -#define _ASM_X86_UNWIND_H - -#define UNW_PC(frame) ((void)(frame), 0UL) -#define UNW_SP(frame) ((void)(frame), 0UL) -#define UNW_FP(frame) ((void)(frame), 0UL) - -static inline int arch_unw_user_mode(const void *info) -{ - return 0; -} - -#endif /* _ASM_X86_UNWIND_H */ diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index ce6650eb64e9..c9a666cdd3db 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -20,7 +20,6 @@ #include #include #include -#include #include #include #include @@ -51,7 +50,6 @@ #include #include #include -#include #include #include #include diff --git a/include/linux/module.h b/include/linux/module.h index 3bfed013350b..03cb93d1865a 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -294,9 +294,6 @@ struct module /* The size of the executable code in each section. */ unsigned int init_text_size, core_text_size; - /* The handle returned from unwind_add_table. */ - void *unwind_info; - /* Arch-specific module values */ struct mod_arch_specific arch; diff --git a/include/linux/unwind.h b/include/linux/unwind.h deleted file mode 100644 index 7760860fa170..000000000000 --- a/include/linux/unwind.h +++ /dev/null @@ -1,68 +0,0 @@ -#ifndef _LINUX_UNWIND_H -#define _LINUX_UNWIND_H - -/* - * Copyright (C) 2002-2006 Novell, Inc. - * Jan Beulich - * This code is released under version 2 of the GNU GPL. - * - * A simple API for unwinding kernel stacks. This is used for - * debugging and error reporting purposes. The kernel doesn't need - * full-blown stack unwinding with all the bells and whistles, so there - * is not much point in implementing the full Dwarf2 unwind API. - */ - -struct module; - -struct unwind_frame_info {}; - -static inline void unwind_init(void) {} -static inline void unwind_setup(void) {} - -#ifdef CONFIG_MODULES - -static inline void *unwind_add_table(struct module *mod, - const void *table_start, - unsigned long table_size) -{ - return NULL; -} - -static inline void unwind_remove_table(void *handle, int init_only) -{ -} - -#endif - -static inline int unwind_init_frame_info(struct unwind_frame_info *info, - struct task_struct *tsk, - const struct pt_regs *regs) -{ - return -ENOSYS; -} - -static inline int unwind_init_blocked(struct unwind_frame_info *info, - struct task_struct *tsk) -{ - return -ENOSYS; -} - -static inline int unwind_init_running(struct unwind_frame_info *info, - asmlinkage int (*cb)(struct unwind_frame_info *, - void *arg), - void *arg) -{ - return -ENOSYS; -} - -static inline int unwind(struct unwind_frame_info *info) -{ - return -ENOSYS; -} - -static inline int unwind_to_user(struct unwind_frame_info *info) -{ - return -ENOSYS; -} - -#endif /* _LINUX_UNWIND_H */ diff --git a/init/main.c b/init/main.c index 90926dadc20d..e119dd28dd7d 100644 --- a/init/main.c +++ b/init/main.c @@ -50,7 +50,6 @@ #include #include #include -#include #include #include #include @@ -537,7 +536,6 @@ asmlinkage void __init start_kernel(void) * Need to run as early as possible, to initialize the * lockdep hash: */ - unwind_init(); lockdep_init(); debug_objects_early_init(); cgroup_init_early(); @@ -559,7 +557,6 @@ asmlinkage void __init start_kernel(void) setup_arch(&command_line); mm_init_owner(&init_mm, &init_task); setup_command_line(command_line); - unwind_setup(); setup_per_cpu_areas(); setup_nr_cpu_ids(); smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */ diff --git a/kernel/module.c b/kernel/module.c index f47cce910f25..34b56cf06615 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -43,7 +43,6 @@ #include #include #include -#include #include #include #include @@ -1449,8 +1448,6 @@ static void free_module(struct module *mod) remove_sect_attrs(mod); mod_kobject_remove(mod); - unwind_remove_table(mod->unwind_info, 0); - /* Arch-specific cleanup. */ module_arch_cleanup(mod); @@ -1867,7 +1864,6 @@ static noinline struct module *load_module(void __user *umod, unsigned int symindex = 0; unsigned int strindex = 0; unsigned int modindex, versindex, infoindex, pcpuindex; - unsigned int unwindex = 0; unsigned int num_kp, num_mcount; struct kernel_param *kp; struct module *mod; @@ -1957,9 +1953,6 @@ static noinline struct module *load_module(void __user *umod, versindex = find_sec(hdr, sechdrs, secstrings, "__versions"); infoindex = find_sec(hdr, sechdrs, secstrings, ".modinfo"); pcpuindex = find_pcpusec(hdr, sechdrs, secstrings); -#ifdef ARCH_UNWIND_SECTION_NAME - unwindex = find_sec(hdr, sechdrs, secstrings, ARCH_UNWIND_SECTION_NAME); -#endif /* Don't keep modinfo and version sections. */ sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC; @@ -1969,8 +1962,6 @@ static noinline struct module *load_module(void __user *umod, sechdrs[symindex].sh_flags |= SHF_ALLOC; sechdrs[strindex].sh_flags |= SHF_ALLOC; #endif - if (unwindex) - sechdrs[unwindex].sh_flags |= SHF_ALLOC; /* Check module struct version now, before we try to use module. */ if (!check_modstruct_version(sechdrs, versindex, mod)) { @@ -2267,11 +2258,6 @@ static noinline struct module *load_module(void __user *umod, add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs); add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs); - /* Size of section 0 is 0, so this works well if no unwind info. */ - mod->unwind_info = unwind_add_table(mod, - (void *)sechdrs[unwindex].sh_addr, - sechdrs[unwindex].sh_size); - /* Get rid of temporary copy */ vfree(hdr); @@ -2370,7 +2356,6 @@ sys_init_module(void __user *umod, mutex_lock(&module_mutex); /* Drop initial reference. */ module_put(mod); - unwind_remove_table(mod->unwind_info, 1); module_free(mod, mod->module_init); mod->module_init = NULL; mod->init_size = 0; diff --git a/lib/fault-inject.c b/lib/fault-inject.c index a50a311554cc..f97af55bdd96 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -6,7 +6,6 @@ #include #include #include -#include #include #include #include -- cgit v1.2.3 From d2e3192b6e372a441c18bc8cb32f89ef38f105b7 Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 6 Jan 2009 14:41:10 -0800 Subject: init/main.c: mark late_time_init as __initdata Signed-off-by: Jan Beulich Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- init/main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'init/main.c') diff --git a/init/main.c b/init/main.c index e119dd28dd7d..b5a892c68375 100644 --- a/init/main.c +++ b/init/main.c @@ -107,7 +107,7 @@ EXPORT_SYMBOL(system_state); extern void time_init(void); /* Default late time init is NULL. archs can override this later. */ -void (*late_time_init)(void); +void (*__initdata late_time_init)(void); extern void softirq_init(void); /* Untouched command line saved by arch-specific code. */ -- cgit v1.2.3 From 22a9d645677feefd402befd02edd59b122289ef1 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Wed, 7 Jan 2009 08:45:46 -0800 Subject: async: Asynchronous function calls to speed up kernel boot Right now, most of the kernel boot is strictly synchronous, such that various hardware delays are done sequentially. In order to make the kernel boot faster, this patch introduces infrastructure to allow doing some of the initialization steps asynchronously, which will hide significant portions of the hardware delays in practice. In order to not change device order and other similar observables, this patch does NOT do full parallel initialization. Rather, it operates more in the way an out of order CPU does; the work may be done out of order and asynchronous, but the observable effects (instruction retiring for the CPU) are still done in the original sequence. Signed-off-by: Arjan van de Ven --- include/linux/async.h | 25 ++++ init/do_mounts.c | 2 + init/main.c | 5 +- kernel/Makefile | 3 +- kernel/async.c | 321 +++++++++++++++++++++++++++++++++++++++++++++++++ kernel/irq/autoprobe.c | 5 + kernel/module.c | 2 + 7 files changed, 361 insertions(+), 2 deletions(-) create mode 100644 include/linux/async.h create mode 100644 kernel/async.c (limited to 'init/main.c') diff --git a/include/linux/async.h b/include/linux/async.h new file mode 100644 index 000000000000..c4ecacd0b327 --- /dev/null +++ b/include/linux/async.h @@ -0,0 +1,25 @@ +/* + * async.h: Asynchronous function calls for boot performance + * + * (C) Copyright 2009 Intel Corporation + * Author: Arjan van de Ven + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ + +#include +#include + +typedef u64 async_cookie_t; +typedef void (async_func_ptr) (void *data, async_cookie_t cookie); + +extern async_cookie_t async_schedule(async_func_ptr *ptr, void *data); +extern async_cookie_t async_schedule_special(async_func_ptr *ptr, void *data, struct list_head *list); +extern void async_synchronize_full(void); +extern void async_synchronize_full_special(struct list_head *list); +extern void async_synchronize_cookie(async_cookie_t cookie); +extern void async_synchronize_cookie_special(async_cookie_t cookie, struct list_head *list); + diff --git a/init/do_mounts.c b/init/do_mounts.c index 5efca73b39f9..708105e163df 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include @@ -372,6 +373,7 @@ void __init prepare_namespace(void) /* wait for the known devices to complete their probing */ while (driver_probe_done() != 0) msleep(100); + async_synchronize_full(); md_run_setup(); diff --git a/init/main.c b/init/main.c index b5a892c68375..f66715d8a853 100644 --- a/init/main.c +++ b/init/main.c @@ -62,6 +62,7 @@ #include #include #include +#include #include #include @@ -684,7 +685,7 @@ asmlinkage void __init start_kernel(void) rest_init(); } -static int initcall_debug; +int initcall_debug; core_param(initcall_debug, initcall_debug, bool, 0644); int do_one_initcall(initcall_t fn) @@ -785,6 +786,8 @@ static void run_init_process(char *init_filename) */ static noinline int init_post(void) { + /* need to finish all async __init code before freeing the memory */ + async_synchronize_full(); free_initmem(); unlock_kernel(); mark_rodata_ro(); diff --git a/kernel/Makefile b/kernel/Makefile index e1c5bf3365c0..2921d90ce32f 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -9,7 +9,8 @@ obj-y = sched.o fork.o exec_domain.o panic.o printk.o \ rcupdate.o extable.o params.o posix-timers.o \ kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \ hrtimer.o rwsem.o nsproxy.o srcu.o semaphore.o \ - notifier.o ksysfs.o pm_qos_params.o sched_clock.o cred.o + notifier.o ksysfs.o pm_qos_params.o sched_clock.o cred.o \ + async.o ifdef CONFIG_FUNCTION_TRACER # Do not trace debug files and internal ftrace files diff --git a/kernel/async.c b/kernel/async.c new file mode 100644 index 000000000000..afaa8a653d5a --- /dev/null +++ b/kernel/async.c @@ -0,0 +1,321 @@ +/* + * async.c: Asynchronous function calls for boot performance + * + * (C) Copyright 2009 Intel Corporation + * Author: Arjan van de Ven + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ + + +/* + +Goals and Theory of Operation + +The primary goal of this feature is to reduce the kernel boot time, +by doing various independent hardware delays and discovery operations +decoupled and not strictly serialized. + +More specifically, the asynchronous function call concept allows +certain operations (primarily during system boot) to happen +asynchronously, out of order, while these operations still +have their externally visible parts happen sequentially and in-order. +(not unlike how out-of-order CPUs retire their instructions in order) + +Key to the asynchronous function call implementation is the concept of +a "sequence cookie" (which, although it has an abstracted type, can be +thought of as a monotonically incrementing number). + +The async core will assign each scheduled event such a sequence cookie and +pass this to the called functions. + +The asynchronously called function should before doing a globally visible +operation, such as registering device numbers, call the +async_synchronize_cookie() function and pass in its own cookie. The +async_synchronize_cookie() function will make sure that all asynchronous +operations that were scheduled prior to the operation corresponding with the +cookie have completed. + +Subsystem/driver initialization code that scheduled asynchronous probe +functions, but which shares global resources with other drivers/subsystems +that do not use the asynchronous call feature, need to do a full +synchronization with the async_synchronize_full() function, before returning +from their init function. This is to maintain strict ordering between the +asynchronous and synchronous parts of the kernel. + +*/ + +#include +#include +#include +#include +#include +#include +#include + +static async_cookie_t next_cookie = 1; + +#define MAX_THREADS 256 +#define MAX_WORK 32768 + +static LIST_HEAD(async_pending); +static LIST_HEAD(async_running); +static DEFINE_SPINLOCK(async_lock); + +struct async_entry { + struct list_head list; + async_cookie_t cookie; + async_func_ptr *func; + void *data; + struct list_head *running; +}; + +static DECLARE_WAIT_QUEUE_HEAD(async_done); +static DECLARE_WAIT_QUEUE_HEAD(async_new); + +static atomic_t entry_count; +static atomic_t thread_count; + +extern int initcall_debug; + + +/* + * MUST be called with the lock held! + */ +static async_cookie_t __lowest_in_progress(struct list_head *running) +{ + struct async_entry *entry; + if (!list_empty(&async_pending)) { + entry = list_first_entry(&async_pending, + struct async_entry, list); + return entry->cookie; + } else if (!list_empty(running)) { + entry = list_first_entry(running, + struct async_entry, list); + return entry->cookie; + } else { + /* nothing in progress... next_cookie is "infinity" */ + return next_cookie; + } + +} +/* + * pick the first pending entry and run it + */ +static void run_one_entry(void) +{ + unsigned long flags; + struct async_entry *entry; + ktime_t calltime, delta, rettime; + + /* 1) pick one task from the pending queue */ + + spin_lock_irqsave(&async_lock, flags); + if (list_empty(&async_pending)) + goto out; + entry = list_first_entry(&async_pending, struct async_entry, list); + + /* 2) move it to the running queue */ + list_del(&entry->list); + list_add_tail(&entry->list, &async_running); + spin_unlock_irqrestore(&async_lock, flags); + + /* 3) run it (and print duration)*/ + if (initcall_debug) { + printk("calling %lli_%pF @ %i\n", entry->cookie, entry->func, task_pid_nr(current)); + calltime = ktime_get(); + } + entry->func(entry->data, entry->cookie); + if (initcall_debug) { + rettime = ktime_get(); + delta = ktime_sub(rettime, calltime); + printk("initcall %lli_%pF returned 0 after %lld usecs\n", entry->cookie, + entry->func, ktime_to_ns(delta) >> 10); + } + + /* 4) remove it from the running queue */ + spin_lock_irqsave(&async_lock, flags); + list_del(&entry->list); + + /* 5) free the entry */ + kfree(entry); + atomic_dec(&entry_count); + + spin_unlock_irqrestore(&async_lock, flags); + + /* 6) wake up any waiters. */ + wake_up(&async_done); + return; + +out: + spin_unlock_irqrestore(&async_lock, flags); +} + + +static async_cookie_t __async_schedule(async_func_ptr *ptr, void *data, struct list_head *running) +{ + struct async_entry *entry; + unsigned long flags; + async_cookie_t newcookie; + + + /* allow irq-off callers */ + entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC); + + /* + * If we're out of memory or if there's too much work + * pending already, we execute synchronously. + */ + if (!entry || atomic_read(&entry_count) > MAX_WORK) { + kfree(entry); + spin_lock_irqsave(&async_lock, flags); + newcookie = next_cookie++; + spin_unlock_irqrestore(&async_lock, flags); + + /* low on memory.. run synchronously */ + ptr(data, newcookie); + return newcookie; + } + entry->func = ptr; + entry->data = data; + entry->running = running; + + spin_lock_irqsave(&async_lock, flags); + newcookie = entry->cookie = next_cookie++; + list_add_tail(&entry->list, &async_pending); + atomic_inc(&entry_count); + spin_unlock_irqrestore(&async_lock, flags); + wake_up(&async_new); + return newcookie; +} + +async_cookie_t async_schedule(async_func_ptr *ptr, void *data) +{ + return __async_schedule(ptr, data, &async_pending); +} +EXPORT_SYMBOL_GPL(async_schedule); + +async_cookie_t async_schedule_special(async_func_ptr *ptr, void *data, struct list_head *running) +{ + return __async_schedule(ptr, data, running); +} +EXPORT_SYMBOL_GPL(async_schedule_special); + +void async_synchronize_full(void) +{ + async_synchronize_cookie(next_cookie); +} +EXPORT_SYMBOL_GPL(async_synchronize_full); + +void async_synchronize_full_special(struct list_head *list) +{ + async_synchronize_cookie_special(next_cookie, list); +} +EXPORT_SYMBOL_GPL(async_synchronize_full_special); + +void async_synchronize_cookie_special(async_cookie_t cookie, struct list_head *running) +{ + ktime_t starttime, delta, endtime; + + if (initcall_debug) { + printk("async_waiting @ %i\n", task_pid_nr(current)); + starttime = ktime_get(); + } + + wait_event(async_done, __lowest_in_progress(running) >= cookie); + + if (initcall_debug) { + endtime = ktime_get(); + delta = ktime_sub(endtime, starttime); + + printk("async_continuing @ %i after %lli usec\n", + task_pid_nr(current), ktime_to_ns(delta) >> 10); + } +} +EXPORT_SYMBOL_GPL(async_synchronize_cookie_special); + +void async_synchronize_cookie(async_cookie_t cookie) +{ + async_synchronize_cookie_special(cookie, &async_running); +} +EXPORT_SYMBOL_GPL(async_synchronize_cookie); + + +static int async_thread(void *unused) +{ + DECLARE_WAITQUEUE(wq, current); + add_wait_queue(&async_new, &wq); + + while (!kthread_should_stop()) { + int ret = HZ; + set_current_state(TASK_INTERRUPTIBLE); + /* + * check the list head without lock.. false positives + * are dealt with inside run_one_entry() while holding + * the lock. + */ + rmb(); + if (!list_empty(&async_pending)) + run_one_entry(); + else + ret = schedule_timeout(HZ); + + if (ret == 0) { + /* + * we timed out, this means we as thread are redundant. + * we sign off and die, but we to avoid any races there + * is a last-straw check to see if work snuck in. + */ + atomic_dec(&thread_count); + wmb(); /* manager must see our departure first */ + if (list_empty(&async_pending)) + break; + /* + * woops work came in between us timing out and us + * signing off; we need to stay alive and keep working. + */ + atomic_inc(&thread_count); + } + } + remove_wait_queue(&async_new, &wq); + + return 0; +} + +static int async_manager_thread(void *unused) +{ + DECLARE_WAITQUEUE(wq, current); + add_wait_queue(&async_new, &wq); + + while (!kthread_should_stop()) { + int tc, ec; + + set_current_state(TASK_INTERRUPTIBLE); + + tc = atomic_read(&thread_count); + rmb(); + ec = atomic_read(&entry_count); + + while (tc < ec && tc < MAX_THREADS) { + kthread_run(async_thread, NULL, "async/%i", tc); + atomic_inc(&thread_count); + tc++; + } + + schedule(); + } + remove_wait_queue(&async_new, &wq); + + return 0; +} + +static int __init async_init(void) +{ + kthread_run(async_manager_thread, NULL, "async/mgr"); + return 0; +} + +core_initcall(async_init); diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c index cc0f7321b8ce..1de9700f416e 100644 --- a/kernel/irq/autoprobe.c +++ b/kernel/irq/autoprobe.c @@ -10,6 +10,7 @@ #include #include #include +#include #include "internals.h" @@ -34,6 +35,10 @@ unsigned long probe_irq_on(void) unsigned int status; int i; + /* + * quiesce the kernel, or at least the asynchronous portion + */ + async_synchronize_full(); mutex_lock(&probing_active); /* * something may have generated an irq long ago and we want to diff --git a/kernel/module.c b/kernel/module.c index 496dcb57b608..c9332c90d5a0 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -50,6 +50,7 @@ #include #include #include +#include #if 0 #define DEBUGP printk @@ -816,6 +817,7 @@ sys_delete_module(const char __user *name_user, unsigned int flags) mod->exit(); blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_GOING, mod); + async_synchronize_full(); mutex_lock(&module_mutex); /* Store the name of the last unloaded module for diagnostic purposes */ strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module)); -- cgit v1.2.3