diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 14 | ||||
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/kernel_lock.c | 123 | ||||
| -rw-r--r-- | lib/scatterlist.c | 294 |
4 files changed, 309 insertions, 124 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a601093..14fb355 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -517,4 +517,18 @@ config FAULT_INJECTION_STACKTRACE_FILTER help Provide stacktrace filter for fault-injection capabilities +config LATENCYTOP + bool "Latency measuring infrastructure" + select FRAME_POINTER if !MIPS + select KALLSYMS + select KALLSYMS_ALL + select STACKTRACE + select SCHEDSTATS + select SCHED_DEBUG + depends on X86 || X86_64 + help + Enable this option if you want to use the LatencyTOP tool + to find out which userspace is blocking on what kernel operations. + + source "samples/Kconfig" diff --git a/lib/Makefile b/lib/Makefile index b6793ed..89841dc 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -6,7 +6,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ rbtree.o radix-tree.o dump_stack.o \ idr.o int_sqrt.o extable.o prio_tree.o \ sha1.o irq_regs.o reciprocal_div.o argv_split.o \ - proportions.o prio_heap.o + proportions.o prio_heap.o scatterlist.o lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o diff --git a/lib/kernel_lock.c b/lib/kernel_lock.c index f73e2f8..812dbf0 100644 --- a/lib/kernel_lock.c +++ b/lib/kernel_lock.c @@ -9,7 +9,6 @@ #include <linux/module.h> #include <linux/kallsyms.h> -#ifdef CONFIG_PREEMPT_BKL /* * The 'big kernel semaphore' * @@ -86,128 +85,6 @@ void __lockfunc unlock_kernel(void) up(&kernel_sem); } -#else - -/* - * The 'big kernel lock' - * - * This spinlock is taken and released recursively by lock_kernel() - * and unlock_kernel(). It is transparently dropped and reacquired - * over schedule(). It is used to protect legacy code that hasn't - * been migrated to a proper locking design yet. - * - * Don't use in new code. - */ -static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kernel_flag); - - -/* - * Acquire/release the underlying lock from the scheduler. - * - * This is called with preemption disabled, and should - * return an error value if it cannot get the lock and - * TIF_NEED_RESCHED gets set. - * - * If it successfully gets the lock, it should increment - * the preemption count like any spinlock does. - * - * (This works on UP too - _raw_spin_trylock will never - * return false in that case) - */ -int __lockfunc __reacquire_kernel_lock(void) -{ - while (!_raw_spin_trylock(&kernel_flag)) { - if (test_thread_flag(TIF_NEED_RESCHED)) - return -EAGAIN; - cpu_relax(); - } - preempt_disable(); - return 0; -} - -void __lockfunc __release_kernel_lock(void) -{ - _raw_spin_unlock(&kernel_flag); - preempt_enable_no_resched(); -} - -/* - * These are the BKL spinlocks - we try to be polite about preemption. - * If SMP is not on (ie UP preemption), this all goes away because the - * _raw_spin_trylock() will always succeed. - */ -#ifdef CONFIG_PREEMPT -static inline void __lock_kernel(void) -{ - preempt_disable(); - if (unlikely(!_raw_spin_trylock(&kernel_flag))) { - /* - * If preemption was disabled even before this - * was called, there's nothing we can be polite - * about - just spin. - */ - if (preempt_count() > 1) { - _raw_spin_lock(&kernel_flag); - return; - } - - /* - * Otherwise, let's wait for the kernel lock - * with preemption enabled.. - */ - do { - preempt_enable(); - while (spin_is_locked(&kernel_flag)) - cpu_relax(); - preempt_disable(); - } while (!_raw_spin_trylock(&kernel_flag)); - } -} - -#else - -/* - * Non-preemption case - just get the spinlock - */ -static inline void __lock_kernel(void) -{ - _raw_spin_lock(&kernel_flag); -} -#endif - -static inline void __unlock_kernel(void) -{ - /* - * the BKL is not covered by lockdep, so we open-code the - * unlocking sequence (and thus avoid the dep-chain ops): - */ - _raw_spin_unlock(&kernel_flag); - preempt_enable(); -} - -/* - * Getting the big kernel lock. - * - * This cannot happen asynchronously, so we only need to - * worry about other CPU's. - */ -void __lockfunc lock_kernel(void) -{ - int depth = current->lock_depth+1; - if (likely(!depth)) - __lock_kernel(); - current->lock_depth = depth; -} - -void __lockfunc unlock_kernel(void) -{ - BUG_ON(current->lock_depth < 0); - if (likely(--current->lock_depth < 0)) - __unlock_kernel(); -} - -#endif - EXPORT_SYMBOL(lock_kernel); EXPORT_SYMBOL(unlock_kernel); diff --git a/lib/scatterlist.c b/lib/scatterlist.c new file mode 100644 index 0000000..acca4901 --- /dev/null +++ b/lib/scatterlist.c @@ -0,0 +1,294 @@ +/* + * Copyright (C) 2007 Jens Axboe <jens.axboe@oracle.com> + * + * Scatterlist handling helpers. + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ +#include <linux/module.h> +#include <linux/scatterlist.h> + +/** + * sg_next - return the next scatterlist entry in a list + * @sg: The current sg entry + * + * Description: + * Usually the next entry will be @sg@ + 1, but if this sg element is part + * of a chained scatterlist, it could jump to the start of a new + * scatterlist array. + * + **/ +struct scatterlist *sg_next(struct scatterlist *sg) +{ +#ifdef CONFIG_DEBUG_SG + BUG_ON(sg->sg_magic != SG_MAGIC); +#endif + if (sg_is_last(sg)) + return NULL; + + sg++; + if (unlikely(sg_is_chain(sg))) + sg = sg_chain_ptr(sg); + + return sg; +} +EXPORT_SYMBOL(sg_next); + +/** + * sg_last - return the last scatterlist entry in a list + * @sgl: First entry in the scatterlist + * @nents: Number of entries in the scatterlist + * + * Description: + * Should only be used casually, it (currently) scans the entire list + * to get the last entry. + * + * Note that the @sgl@ pointer passed in need not be the first one, + * the important bit is that @nents@ denotes the number of entries that + * exist from @sgl@. + * + **/ +struct scatterlist *sg_last(struct scatterlist *sgl, unsigned int nents) +{ +#ifndef ARCH_HAS_SG_CHAIN + struct scatterlist *ret = &sgl[nents - 1]; +#else + struct scatterlist *sg, *ret = NULL; + unsigned int i; + + for_each_sg(sgl, sg, nents, i) + ret = sg; + +#endif +#ifdef CONFIG_DEBUG_SG + BUG_ON(sgl[0].sg_magic != SG_MAGIC); + BUG_ON(!sg_is_last(ret)); +#endif + return ret; +} +EXPORT_SYMBOL(sg_last); + +/** + * sg_init_table - Initialize SG table + * @sgl: The SG table + * @nents: Number of entries in table + * + * Notes: + * If this is part of a chained sg table, sg_mark_end() should be + * used only on the last table part. + * + **/ +void sg_init_table(struct scatterlist *sgl, unsigned int nents) +{ + memset(sgl, 0, sizeof(*sgl) * nents); +#ifdef CONFIG_DEBUG_SG + { + unsigned int i; + for (i = 0; i < nents; i++) + sgl[i].sg_magic = SG_MAGIC; + } +#endif + sg_mark_end(&sgl[nents - 1]); +} +EXPORT_SYMBOL(sg_init_table); + +/** + * sg_init_one - Initialize a single entry sg list + * @sg: SG entry + * @buf: Virtual address for IO + * @buflen: IO length + * + **/ +void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen) +{ + sg_init_table(sg, 1); + sg_set_buf(sg, buf, buflen); +} +EXPORT_SYMBOL(sg_init_one); + +/* + * The default behaviour of sg_alloc_table() is to use these kmalloc/kfree + * helpers. + */ +static struct scatterlist *sg_kmalloc(unsigned int nents, gfp_t gfp_mask) +{ + if (nents == SG_MAX_SINGLE_ALLOC) + return (struct scatterlist *) __get_free_page(gfp_mask); + else + return kmalloc(nents * sizeof(struct scatterlist), gfp_mask); +} + +static void sg_kfree(struct scatterlist *sg, unsigned int nents) +{ + if (nents == SG_MAX_SINGLE_ALLOC) + free_page((unsigned long) sg); + else + kfree(sg); +} + +/** + * __sg_free_table - Free a previously mapped sg table + * @table: The sg table header to use + * @max_ents: The maximum number of entries per single scatterlist + * @free_fn: Free function + * + * Description: + * Free an sg table previously allocated and setup with + * __sg_alloc_table(). The @max_ents value must be identical to + * that previously used with __sg_alloc_table(). + * + **/ +void __sg_free_table(struct sg_table *table, unsigned int max_ents, + sg_free_fn *free_fn) +{ + struct scatterlist *sgl, *next; + + if (unlikely(!table->sgl)) + return; + + sgl = table->sgl; + while (table->orig_nents) { + unsigned int alloc_size = table->orig_nents; + unsigned int sg_size; + + /* + * If we have more than max_ents segments left, + * then assign 'next' to the sg table after the current one. + * sg_size is then one less than alloc size, since the last + * element is the chain pointer. + */ + if (alloc_size > max_ents) { + next = sg_chain_ptr(&sgl[max_ents - 1]); + alloc_size = max_ents; + sg_size = alloc_size - 1; + } else { + sg_size = alloc_size; + next = NULL; + } + + table->orig_nents -= sg_size; + free_fn(sgl, alloc_size); + sgl = next; + } + + table->sgl = NULL; +} +EXPORT_SYMBOL(__sg_free_table); + +/** + * sg_free_table - Free a previously allocated sg table + * @table: The mapped sg table header + * + **/ +void sg_free_table(struct sg_table *table) +{ + __sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree); +} +EXPORT_SYMBOL(sg_free_table); + +/** + * __sg_alloc_table - Allocate and initialize an sg table with given allocator + * @table: The sg table header to use + * @nents: Number of entries in sg list + * @max_ents: The maximum number of entries the allocator returns per call + * @gfp_mask: GFP allocation mask + * @alloc_fn: Allocator to use + * + * Description: + * This function returns a @table @nents long. The allocator is + * defined to return scatterlist chunks of maximum size @max_ents. + * Thus if @nents is bigger than @max_ents, the scatterlists will be + * chained in units of @max_ents. + * + * Notes: + * If this function returns non-0 (eg failure), the caller must call + * __sg_free_table() to cleanup any leftover allocations. + * + **/ +int __sg_alloc_table(struct sg_table *table, unsigned int nents, + unsigned int max_ents, gfp_t gfp_mask, + sg_alloc_fn *alloc_fn) +{ + struct scatterlist *sg, *prv; + unsigned int left; + +#ifndef ARCH_HAS_SG_CHAIN + BUG_ON(nents > max_ents); +#endif + + memset(table, 0, sizeof(*table)); + + left = nents; + prv = NULL; + do { + unsigned int sg_size, alloc_size = left; + + if (alloc_size > max_ents) { + alloc_size = max_ents; + sg_size = alloc_size - 1; + } else + sg_size = alloc_size; + + left -= sg_size; + + sg = alloc_fn(alloc_size, gfp_mask); + if (unlikely(!sg)) + return -ENOMEM; + + sg_init_table(sg, alloc_size); + table->nents = table->orig_nents += sg_size; + + /* + * If this is the first mapping, assign the sg table header. + * If this is not the first mapping, chain previous part. + */ + if (prv) + sg_chain(prv, max_ents, sg); + else + table->sgl = sg; + + /* + * If no more entries after this one, mark the end + */ + if (!left) + sg_mark_end(&sg[sg_size - 1]); + + /* + * only really needed for mempool backed sg allocations (like + * SCSI), a possible improvement here would be to pass the + * table pointer into the allocator and let that clear these + * flags + */ + gfp_mask &= ~__GFP_WAIT; + gfp_mask |= __GFP_HIGH; + prv = sg; + } while (left); + + return 0; +} +EXPORT_SYMBOL(__sg_alloc_table); + +/** + * sg_alloc_table - Allocate and initialize an sg table + * @table: The sg table header to use + * @nents: Number of entries in sg list + * @gfp_mask: GFP allocation mask + * + * Description: + * Allocate and initialize an sg table. If @nents@ is larger than + * SG_MAX_SINGLE_ALLOC a chained sg table will be setup. + * + **/ +int sg_alloc_table(struct sg_table *table, unsigned int nents, gfp_t gfp_mask) +{ + int ret; + + ret = __sg_alloc_table(table, nents, SG_MAX_SINGLE_ALLOC, + gfp_mask, sg_kmalloc); + if (unlikely(ret)) + __sg_free_table(table, SG_MAX_SINGLE_ALLOC, sg_kfree); + + return ret; +} +EXPORT_SYMBOL(sg_alloc_table); |
