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mdbx: fix/rework cache-line alignment.

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This commit is contained in:
Leo Yuriev
2018-03-22 20:34:09 +03:00
parent 6a074cb85a
commit 61a2c56784
4 changed files with 47 additions and 43 deletions
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59
src/bits.h
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@@ -55,6 +55,7 @@
#pragma warning(disable : 4310) /* cast truncates constant value */
#pragma warning(disable : 4820) /* bytes padding added after data member for aligment */
#pragma warning(disable : 4548) /* expression before comma has no effect; expected expression with side - effect */
#pragma warning(disable : 4366) /* the result of the unary '&' operator may be unaligned */
#endif /* _MSC_VER (warnings) */
#include "../mdbx.h"
@@ -252,7 +253,7 @@ typedef struct MDBX_reader {
uint8_t pad[MDBX_CACHELINE_SIZE -
(sizeof(txnid_t) + sizeof(mdbx_pid_t) + sizeof(mdbx_tid_t)) %
MDBX_CACHELINE_SIZE];
} __cache_aligned MDBX_reader;
} MDBX_reader;
/* Information about a single database in the environment. */
typedef struct MDBX_db {
@@ -410,42 +411,50 @@ typedef struct MDBX_lockinfo {
/* Flags which environment was opened. */
volatile uint32_t mti_envmode;
union {
#ifdef MDBX_OSAL_LOCK
/* Mutex protecting write access to this table. */
union {
MDBX_OSAL_LOCK mti_wmutex;
uint8_t pad_mti_wmutex[MDBX_OSAL_LOCK_SIZE % sizeof(size_t)];
};
#endif
uint64_t align_wmutex;
};
#define MDBX_lockinfo_SIZE_A \
(8 /* mti_magic_and_version */ + 4 /* mti_os_and_format */ + \
4 /* mti_envmode */ + MDBX_OSAL_LOCK_SIZE /* mti_wmutex */ + \
MDBX_OSAL_LOCK_SIZE % sizeof(size_t) /* pad_mti_wmutex */)
union {
/* The number of slots that have been used in the reader table.
* This always records the maximum count, it is not decremented
* when readers release their slots. */
volatile unsigned __cache_aligned mti_numreaders;
uint64_t align_numreaders;
};
/* cache-line alignment */
uint8_t
pad_a[MDBX_CACHELINE_SIZE - MDBX_lockinfo_SIZE_A % MDBX_CACHELINE_SIZE];
/* The number of slots that have been used in the reader table.
* This always records the maximum count, it is not decremented
* when readers release their slots. */
volatile unsigned mti_numreaders;
union {
#ifdef MDBX_OSAL_LOCK
/* Mutex protecting access to this table. */
/* Mutex protecting readers registration access to this table. */
union {
MDBX_OSAL_LOCK mti_rmutex;
uint8_t pad_mti_rmutex[MDBX_OSAL_LOCK_SIZE % sizeof(size_t)];
};
#endif
uint64_t align_rmutex;
};
union {
volatile txnid_t mti_oldest;
uint64_t align_oldest;
};
volatile txnid_t mti_oldest;
volatile uint32_t mti_readers_refresh_flag;
union {
volatile uint32_t mti_readers_refresh_flag;
uint64_t align_reader_finished_flag;
};
#define MDBX_lockinfo_SIZE_B \
(sizeof(unsigned) /* mti_numreaders */ + \
MDBX_OSAL_LOCK_SIZE /* mti_rmutex */ + sizeof(txnid_t) /* mti_oldest */ + \
sizeof(uint32_t) /* mti_readers_refresh_flag */ + \
MDBX_OSAL_LOCK_SIZE % sizeof(size_t) /* pad_mti_rmutex */)
uint8_t pad_align[MDBX_CACHELINE_SIZE - sizeof(uint64_t) * 7];
/* cache-line alignment */
uint8_t
pad_b[MDBX_CACHELINE_SIZE - MDBX_lockinfo_SIZE_B % MDBX_CACHELINE_SIZE];
MDBX_reader mti_readers[1];
MDBX_reader __cache_aligned mti_readers[1];
} MDBX_lockinfo;
#pragma pack(pop)