From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Herbert Subject: [PATCH net-next 2/7] spinlock: Add library function to allocate spinlock buckets array Date: Wed, 14 Sep 2016 16:22:51 -0700 Message-ID: <1473895376-347096-3-git-send-email-tom@herbertland.com> References: <1473895376-347096-1-git-send-email-tom@herbertland.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , To: , Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:48202 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756385AbcINXXk (ORCPT ); Wed, 14 Sep 2016 19:23:40 -0400 Received: from pps.filterd (m0001255.ppops.net [127.0.0.1]) by mx0b-00082601.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u8ENLsSP018428 for ; Wed, 14 Sep 2016 16:23:39 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0b-00082601.pphosted.com with ESMTP id 25f0w2670y-4 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 14 Sep 2016 16:23:37 -0700 Received: from facebook.com (2401:db00:21:6030:face:0:92:0) by mx-out.facebook.com (10.102.107.97) with ESMTP id 312207167ad211e6bde70002c99331b0-c37f5a50 for ; Wed, 14 Sep 2016 16:23:06 -0700 In-Reply-To: <1473895376-347096-1-git-send-email-tom@herbertland.com> Sender: netdev-owner@vger.kernel.org List-ID: Add two new library functions alloc_bucket_spinlocks and free_bucket_spinlocks. These are use to allocate and free an array of spinlocks that are useful as locks for hash buckets. The interface specifies the maximum number of spinlocks in the array as well as a CPU multiplier to derive the number of spinlocks to allocate. The number to allocated is rounded up to a power of two to make the array amenable to hash lookup. Reviewed by Greg Rose Acked-by: Thomas Graf Signed-off-by: Tom Herbert --- include/linux/spinlock.h | 6 +++++ lib/Makefile | 2 +- lib/bucket_locks.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 70 insertions(+), 1 deletion(-) create mode 100644 lib/bucket_locks.c diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h index 47dd0ce..4ebdfbf 100644 --- a/include/linux/spinlock.h +++ b/include/linux/spinlock.h @@ -416,4 +416,10 @@ extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock); #define atomic_dec_and_lock(atomic, lock) \ __cond_lock(lock, _atomic_dec_and_lock(atomic, lock)) +int alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *lock_mask, + unsigned int max_size, unsigned int cpu_mult, + gfp_t gfp); + +void free_bucket_spinlocks(spinlock_t *locks); + #endif /* __LINUX_SPINLOCK_H */ diff --git a/lib/Makefile b/lib/Makefile index 5dc77a8..f91185e 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -36,7 +36,7 @@ obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \ gcd.o lcm.o list_sort.o uuid.o flex_array.o iov_iter.o clz_ctz.o \ bsearch.o find_bit.o llist.o memweight.o kfifo.o \ percpu-refcount.o percpu_ida.o rhashtable.o reciprocal_div.o \ - once.o + once.o bucket_locks.o obj-y += string_helpers.o obj-$(CONFIG_TEST_STRING_HELPERS) += test-string_helpers.o obj-y += hexdump.o diff --git a/lib/bucket_locks.c b/lib/bucket_locks.c new file mode 100644 index 0000000..bb9bf11 --- /dev/null +++ b/lib/bucket_locks.c @@ -0,0 +1,63 @@ +#include +#include +#include +#include +#include + +/* Allocate an array of spinlocks to be accessed by a hash. Two arguments + * indicate the number of elements to allocate in the array. max_size + * gives the maximum number of elements to allocate. cpu_mult gives + * the number of locks per CPU to allocate. The size is rounded up + * to a power of 2 to be suitable as a hash table. + */ +int alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *locks_mask, + unsigned int max_size, unsigned int cpu_mult, + gfp_t gfp) +{ + unsigned int i, size; +#if defined(CONFIG_PROVE_LOCKING) + unsigned int nr_pcpus = 2; +#else + unsigned int nr_pcpus = num_possible_cpus(); +#endif + spinlock_t *tlocks = NULL; + + if (cpu_mult) { + nr_pcpus = min_t(unsigned int, nr_pcpus, 64UL); + size = min_t(unsigned int, nr_pcpus * cpu_mult, max_size); + } else { + size = max_size; + } + size = roundup_pow_of_two(size); + + if (!size) + return -EINVAL; + + if (sizeof(spinlock_t) != 0) { +#ifdef CONFIG_NUMA + if (size * sizeof(spinlock_t) > PAGE_SIZE && + gfp == GFP_KERNEL) + tlocks = vmalloc(size * sizeof(spinlock_t)); +#endif + if (gfp != GFP_KERNEL) + gfp |= __GFP_NOWARN | __GFP_NORETRY; + + if (!tlocks) + tlocks = kmalloc_array(size, sizeof(spinlock_t), gfp); + if (!tlocks) + return -ENOMEM; + for (i = 0; i < size; i++) + spin_lock_init(&tlocks[i]); + } + *locks = tlocks; + *locks_mask = size - 1; + + return 0; +} +EXPORT_SYMBOL(alloc_bucket_spinlocks); + +void free_bucket_spinlocks(spinlock_t *locks) +{ + kvfree(locks); +} +EXPORT_SYMBOL(free_bucket_spinlocks); -- 2.8.0.rc2