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| author | Marko Mäkelä <marko.makela@mariadb.com> | 2018-10-05 17:40:06 +0300 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2018-10-05 17:40:06 +0300 |
| commit | 079d0a8724aa3faa3117554c44b81965df457ef3 (patch) | |
| tree | a9d5eb7db1bed39764c7367441f00e46b74ddfbc | |
| parent | 1655053ac1c0b175d860defa2819b29642f664a7 (diff) | |
| parent | 15803fce92a9e3ec7daab79d21990b499b1a709e (diff) | |
| download | mariadb-git-079d0a8724aa3faa3117554c44b81965df457ef3.tar.gz | |
Merge pull request #876 from tempesta-tech/tt-10.1-MDEV-17313-counter-race
MDEV-17313 Data race in ib_counter_t
| -rw-r--r-- | storage/innobase/include/ut0counter.h | 46 | ||||
| -rw-r--r-- | storage/xtradb/include/ut0counter.h | 46 |
2 files changed, 54 insertions, 38 deletions
diff --git a/storage/innobase/include/ut0counter.h b/storage/innobase/include/ut0counter.h index edc0db3b03d..6fde8a7a638 100644 --- a/storage/innobase/include/ut0counter.h +++ b/storage/innobase/include/ut0counter.h @@ -32,6 +32,7 @@ Created 2012/04/12 by Sunny Bains #include <string.h> #include "os0thread.h" #include "os0sync.h" +#include "my_atomic.h" /** Default number of slots to use in ib_counter_t */ #define IB_N_SLOTS 64 @@ -81,8 +82,8 @@ struct thread_id_indexer_t : public generic_indexer_t<Type, N> { } }; -/** Class for using fuzzy counters. The counter is not protected by any -mutex and the results are not guaranteed to be 100% accurate but close +/** Class for using fuzzy counters. The counter is relaxed atomic +so the results are not guaranteed to be 100% accurate but close enough. Creates an array of counters and separates each element by the CACHE_LINE_SIZE bytes */ template < @@ -91,20 +92,6 @@ template < template<typename, int> class Indexer = thread_id_indexer_t> struct MY_ALIGNED(CACHE_LINE_SIZE) ib_counter_t { -#ifdef UNIV_DEBUG - ~ib_counter_t() - { - size_t n = (CACHE_LINE_SIZE / sizeof(Type)); - - /* Check that we aren't writing outside our defined bounds. */ - for (size_t i = 0; i < UT_ARR_SIZE(m_counter); i += n) { - for (size_t j = 1; j < n - 1; ++j) { - ut_ad(m_counter[i + j] == 0); - } - } - } -#endif /* UNIV_DEBUG */ - /** Increment the counter by 1. */ void inc() UNIV_NOTHROW { add(1); } @@ -124,15 +111,36 @@ struct MY_ALIGNED(CACHE_LINE_SIZE) ib_counter_t ut_ad(i < UT_ARR_SIZE(m_counter)); - m_counter[i] += n; + if (sizeof(Type) == 8) { + my_atomic_add64_explicit( + reinterpret_cast<int64*>(&m_counter[i]), + static_cast<int64>(n), MY_MEMORY_ORDER_RELAXED); + } else if (sizeof(Type) == 4) { + my_atomic_add32_explicit( + reinterpret_cast<int32*>(&m_counter[i]), + static_cast<int32>(n), MY_MEMORY_ORDER_RELAXED); + } + compile_time_assert(sizeof(Type) == 8 || sizeof(Type) == 4); } - /* @return total value - not 100% accurate, since it is not atomic. */ + /* @return total value - not 100% accurate, since it is relaxed atomic. */ operator Type() const UNIV_NOTHROW { Type total = 0; for (size_t i = 0; i < N; ++i) { - total += m_counter[m_policy.offset(i)]; + if (sizeof(Type) == 8) { + total += static_cast< + Type>(my_atomic_load64_explicit( + reinterpret_cast<int64*>(const_cast<Type*>( + &m_counter[m_policy.offset(i)])), + MY_MEMORY_ORDER_RELAXED)); + } else if (sizeof(Type) == 4) { + total += static_cast< + Type>(my_atomic_load32_explicit( + reinterpret_cast<int32*>(const_cast<Type*>( + &m_counter[m_policy.offset(i)])), + MY_MEMORY_ORDER_RELAXED)); + } } return(total); diff --git a/storage/xtradb/include/ut0counter.h b/storage/xtradb/include/ut0counter.h index edc0db3b03d..6fde8a7a638 100644 --- a/storage/xtradb/include/ut0counter.h +++ b/storage/xtradb/include/ut0counter.h @@ -32,6 +32,7 @@ Created 2012/04/12 by Sunny Bains #include <string.h> #include "os0thread.h" #include "os0sync.h" +#include "my_atomic.h" /** Default number of slots to use in ib_counter_t */ #define IB_N_SLOTS 64 @@ -81,8 +82,8 @@ struct thread_id_indexer_t : public generic_indexer_t<Type, N> { } }; -/** Class for using fuzzy counters. The counter is not protected by any -mutex and the results are not guaranteed to be 100% accurate but close +/** Class for using fuzzy counters. The counter is relaxed atomic +so the results are not guaranteed to be 100% accurate but close enough. Creates an array of counters and separates each element by the CACHE_LINE_SIZE bytes */ template < @@ -91,20 +92,6 @@ template < template<typename, int> class Indexer = thread_id_indexer_t> struct MY_ALIGNED(CACHE_LINE_SIZE) ib_counter_t { -#ifdef UNIV_DEBUG - ~ib_counter_t() - { - size_t n = (CACHE_LINE_SIZE / sizeof(Type)); - - /* Check that we aren't writing outside our defined bounds. */ - for (size_t i = 0; i < UT_ARR_SIZE(m_counter); i += n) { - for (size_t j = 1; j < n - 1; ++j) { - ut_ad(m_counter[i + j] == 0); - } - } - } -#endif /* UNIV_DEBUG */ - /** Increment the counter by 1. */ void inc() UNIV_NOTHROW { add(1); } @@ -124,15 +111,36 @@ struct MY_ALIGNED(CACHE_LINE_SIZE) ib_counter_t ut_ad(i < UT_ARR_SIZE(m_counter)); - m_counter[i] += n; + if (sizeof(Type) == 8) { + my_atomic_add64_explicit( + reinterpret_cast<int64*>(&m_counter[i]), + static_cast<int64>(n), MY_MEMORY_ORDER_RELAXED); + } else if (sizeof(Type) == 4) { + my_atomic_add32_explicit( + reinterpret_cast<int32*>(&m_counter[i]), + static_cast<int32>(n), MY_MEMORY_ORDER_RELAXED); + } + compile_time_assert(sizeof(Type) == 8 || sizeof(Type) == 4); } - /* @return total value - not 100% accurate, since it is not atomic. */ + /* @return total value - not 100% accurate, since it is relaxed atomic. */ operator Type() const UNIV_NOTHROW { Type total = 0; for (size_t i = 0; i < N; ++i) { - total += m_counter[m_policy.offset(i)]; + if (sizeof(Type) == 8) { + total += static_cast< + Type>(my_atomic_load64_explicit( + reinterpret_cast<int64*>(const_cast<Type*>( + &m_counter[m_policy.offset(i)])), + MY_MEMORY_ORDER_RELAXED)); + } else if (sizeof(Type) == 4) { + total += static_cast< + Type>(my_atomic_load32_explicit( + reinterpret_cast<int32*>(const_cast<Type*>( + &m_counter[m_policy.offset(i)])), + MY_MEMORY_ORDER_RELAXED)); + } } return(total); |