From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965825AbcBDNNE (ORCPT ); Thu, 4 Feb 2016 08:13:04 -0500 Received: from mx2.parallels.com ([199.115.105.18]:56444 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964999AbcBDNM6 (ORCPT ); Thu, 4 Feb 2016 08:12:58 -0500 Subject: Re: + kernel-locking-lockdepc-make-lockdep-initialize-itself-on-demand.patch added to -mm tree To: Andrew Morton , Ingo Molnar , , , , , Peter Zijlstra , Thomas Gleixner References: <56b11d2d.vVw1kB2la7Y+70xF%akpm@linux-foundation.org> <20160203074430.GA32652@gmail.com> <20160203085111.fc3f2631.akpm@linux-foundation.org> <20160203124009.0325b983b74fa15082f13f4d@linux-foundation.org> <20160203134403.aa944de2a3863b9a4beccf63@linux-foundation.org> From: Andrey Ryabinin Message-ID: <56B34E87.1030604@virtuozzo.com> Date: Thu, 4 Feb 2016 16:13:43 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: <20160203134403.aa944de2a3863b9a4beccf63@linux-foundation.org> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: US-EXCH2.sw.swsoft.com (10.255.249.46) To US-EXCH.sw.swsoft.com (10.255.249.47) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/04/2016 12:44 AM, Andrew Morton wrote: > > Probably lockdep_init() and lockdep_initialized can be done away with now. > Yup, it probably should be folded into your patch, or we could hold this off for 4.6. From: Andrey Ryabinin Subject: kernel/lockdep: eliminate lockdep_init() Lockdep is initialized at compile time now. Get rid of lockdep_init(). Signed-off-by: Andrey Ryabinin --- arch/c6x/kernel/setup.c | 2 - arch/microblaze/kernel/setup.c | 2 - arch/powerpc/kernel/setup_32.c | 2 - arch/powerpc/kernel/setup_64.c | 3 -- arch/s390/kernel/early.c | 1 - arch/sparc/kernel/head_64.S | 8 ---- arch/x86/lguest/boot.c | 6 --- include/linux/lockdep.h | 2 - init/main.c | 5 --- kernel/locking/lockdep.c | 59 --------------------------- tools/lib/lockdep/common.c | 5 --- tools/lib/lockdep/include/liblockdep/common.h | 1 - tools/lib/lockdep/preload.c | 2 - 13 files changed, 98 deletions(-) diff --git a/arch/c6x/kernel/setup.c b/arch/c6x/kernel/setup.c index 72e17f7..786e36e 100644 --- a/arch/c6x/kernel/setup.c +++ b/arch/c6x/kernel/setup.c @@ -281,8 +281,6 @@ notrace void __init machine_init(unsigned long dt_ptr) */ set_ist(_vectors_start); - lockdep_init(); - /* * dtb is passed in from bootloader. * fdt is linked in blob. diff --git a/arch/microblaze/kernel/setup.c b/arch/microblaze/kernel/setup.c index 89a2a93..f31ebb5 100644 --- a/arch/microblaze/kernel/setup.c +++ b/arch/microblaze/kernel/setup.c @@ -130,8 +130,6 @@ void __init machine_early_init(const char *cmdline, unsigned int ram, memset(__bss_start, 0, __bss_stop-__bss_start); memset(_ssbss, 0, _esbss-_ssbss); - lockdep_init(); - /* initialize device tree for usage in early_printk */ early_init_devtree(_fdt_start); diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c index ad8c9db..d544fa3 100644 --- a/arch/powerpc/kernel/setup_32.c +++ b/arch/powerpc/kernel/setup_32.c @@ -114,8 +114,6 @@ extern unsigned int memset_nocache_branch; /* Insn to be replaced by NOP */ notrace void __init machine_init(u64 dt_ptr) { - lockdep_init(); - /* Enable early debugging if any specified (see udbg.h) */ udbg_early_init(); diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 5c03a6a..f98be83 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -255,9 +255,6 @@ void __init early_setup(unsigned long dt_ptr) setup_paca(&boot_paca); fixup_boot_paca(); - /* Initialize lockdep early or else spinlocks will blow */ - lockdep_init(); - /* -------- printk is now safe to use ------- */ /* Enable early debugging if any specified (see udbg.h) */ diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index c55576b..a0684de 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -448,7 +448,6 @@ void __init startup_init(void) rescue_initrd(); clear_bss_section(); init_kernel_storage_key(); - lockdep_init(); lockdep_off(); setup_lowcore_early(); setup_facility_list(); diff --git a/arch/sparc/kernel/head_64.S b/arch/sparc/kernel/head_64.S index f2d30ca..cd1f592 100644 --- a/arch/sparc/kernel/head_64.S +++ b/arch/sparc/kernel/head_64.S @@ -696,14 +696,6 @@ tlb_fixup_done: call __bzero sub %o1, %o0, %o1 -#ifdef CONFIG_LOCKDEP - /* We have this call this super early, as even prom_init can grab - * spinlocks and thus call into the lockdep code. - */ - call lockdep_init - nop -#endif - call prom_init mov %l7, %o0 ! OpenPROM cif handler diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 4ba229a..f56cc41 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1520,12 +1520,6 @@ __init void lguest_init(void) */ reserve_top_address(lguest_data.reserve_mem); - /* - * If we don't initialize the lock dependency checker now, it crashes - * atomic_notifier_chain_register, then paravirt_disable_iospace. - */ - lockdep_init(); - /* Hook in our special panic hypercall code. */ atomic_notifier_chain_register(&panic_notifier_list, &paniced); diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 4dca42f..d026b19 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -261,7 +261,6 @@ struct held_lock { /* * Initialization, self-test and debugging-output methods: */ -extern void lockdep_init(void); extern void lockdep_info(void); extern void lockdep_reset(void); extern void lockdep_reset_lock(struct lockdep_map *lock); @@ -392,7 +391,6 @@ static inline void lockdep_on(void) # define lockdep_set_current_reclaim_state(g) do { } while (0) # define lockdep_clear_current_reclaim_state() do { } while (0) # define lockdep_trace_alloc(g) do { } while (0) -# define lockdep_init() do { } while (0) # define lockdep_info() do { } while (0) # define lockdep_init_map(lock, name, key, sub) \ do { (void)(name); (void)(key); } while (0) diff --git a/init/main.c b/init/main.c index 58c9e37..b3008bc 100644 --- a/init/main.c +++ b/init/main.c @@ -499,11 +499,6 @@ asmlinkage __visible void __init start_kernel(void) char *command_line; char *after_dashes; - /* - * Need to run as early as possible, to initialize the - * lockdep hash: - */ - lockdep_init(); set_task_stack_end_magic(&init_task); smp_setup_processor_id(); debug_objects_early_init(); diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 92e4dc6..c873a51 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -123,8 +123,6 @@ static inline int debug_locks_off_graph_unlock(void) return ret; } -static int lockdep_initialized; - unsigned long nr_list_entries; static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; @@ -434,19 +432,6 @@ unsigned int max_lockdep_depth; #ifdef CONFIG_DEBUG_LOCKDEP /* - * We cannot printk in early bootup code. Not even early_printk() - * might work. So we mark any initialization errors and printk - * about it later on, in lockdep_info(). - */ -static int lockdep_init_error; -static const char *lock_init_error; -static unsigned long lockdep_init_trace_data[20]; -static struct stack_trace lockdep_init_trace = { - .max_entries = ARRAY_SIZE(lockdep_init_trace_data), - .entries = lockdep_init_trace_data, -}; - -/* * Various lockdep statistics: */ DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); @@ -669,20 +654,6 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) struct hlist_head *hash_head; struct lock_class *class; -#ifdef CONFIG_DEBUG_LOCKDEP - /* - * If the architecture calls into lockdep before initializing - * the hashes then we'll warn about it later. (we cannot printk - * right now) - */ - if (unlikely(!lockdep_initialized)) { - lockdep_init(); - lockdep_init_error = 1; - lock_init_error = lock->name; - save_stack_trace(&lockdep_init_trace); - } -#endif - if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { debug_locks_off(); printk(KERN_ERR @@ -4013,28 +3984,6 @@ out_restore: raw_local_irq_restore(flags); } -void lockdep_init(void) -{ - int i; - - /* - * Some architectures have their own start_kernel() - * code which calls lockdep_init(), while we also - * call lockdep_init() from the start_kernel() itself, - * and we want to initialize the hashes only once: - */ - if (lockdep_initialized) - return; - - for (i = 0; i < CLASSHASH_SIZE; i++) - INIT_HLIST_HEAD(classhash_table + i); - - for (i = 0; i < CHAINHASH_SIZE; i++) - INIT_HLIST_HEAD(chainhash_table + i); - - lockdep_initialized = 1; -} - void __init lockdep_info(void) { printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); @@ -4061,14 +4010,6 @@ void __init lockdep_info(void) printk(" per task-struct memory footprint: %lu bytes\n", sizeof(struct held_lock) * MAX_LOCK_DEPTH); - -#ifdef CONFIG_DEBUG_LOCKDEP - if (lockdep_init_error) { - printk("WARNING: lockdep init error: lock '%s' was acquired before lockdep_init().\n", lock_init_error); - printk("Call stack leading to lockdep invocation was:\n"); - print_stack_trace(&lockdep_init_trace, 0); - } -#endif } static void diff --git a/tools/lib/lockdep/common.c b/tools/lib/lockdep/common.c index 9be6633..d1c89cc 100644 --- a/tools/lib/lockdep/common.c +++ b/tools/lib/lockdep/common.c @@ -11,11 +11,6 @@ static __thread struct task_struct current_obj; bool debug_locks = true; bool debug_locks_silent; -__attribute__((constructor)) static void liblockdep_init(void) -{ - lockdep_init(); -} - __attribute__((destructor)) static void liblockdep_exit(void) { debug_check_no_locks_held(); diff --git a/tools/lib/lockdep/include/liblockdep/common.h b/tools/lib/lockdep/include/liblockdep/common.h index a60c14b..6e66277 100644 --- a/tools/lib/lockdep/include/liblockdep/common.h +++ b/tools/lib/lockdep/include/liblockdep/common.h @@ -44,7 +44,6 @@ void lock_acquire(struct lockdep_map *lock, unsigned int subclass, void lock_release(struct lockdep_map *lock, int nested, unsigned long ip); extern void debug_check_no_locks_freed(const void *from, unsigned long len); -extern void lockdep_init(void); #define STATIC_LOCKDEP_MAP_INIT(_name, _key) \ { .name = (_name), .key = (void *)(_key), } diff --git a/tools/lib/lockdep/preload.c b/tools/lib/lockdep/preload.c index 21cdf86..5284484 100644 --- a/tools/lib/lockdep/preload.c +++ b/tools/lib/lockdep/preload.c @@ -439,7 +439,5 @@ __attribute__((constructor)) static void init_preload(void) ll_pthread_rwlock_unlock = dlsym(RTLD_NEXT, "pthread_rwlock_unlock"); #endif - lockdep_init(); - __init_state = done; } -- 2.4.10