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Allocate shared buffer and its data in one chunk

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The GWBUF shared buffer and its data is now allocated in one
chunk so that the data directly follows the shared buffer.
That way, creating a GWBUF will involve 2 and not 3 calls to
malloc and freeing one will involve 2 and not 3 calls to free.
This commit is contained in:
Johan Wikman
2017-10-06 15:13:29 +03:00
parent e8f8a3bcdb
commit 5d18ab86ea
2 changed files with 5 additions and 13 deletions
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4
include/maxscale/buffer.h
View File

@ -105,10 +105,10 @@ struct buffer_object_st
*/ */
typedef struct typedef struct
{ {
unsigned char *data; /*< Physical memory that was allocated */ int32_t refcount; /*< Reference count on the buffer */
int refcount; /*< Reference count on the buffer */
buffer_object_t *bufobj; /*< List of objects referred to by GWBUF */ buffer_object_t *bufobj; /*< List of objects referred to by GWBUF */
uint32_t info; /*< Info bits */ uint32_t info; /*< Info bits */
unsigned char data[1]; /*< Actual memory that was allocated */
} SHARED_BUF; } SHARED_BUF;
/** /**

14
server/core/buffer.cc
View File

@ -55,6 +55,7 @@ gwbuf_alloc(unsigned int size)
{ {
GWBUF *rval; GWBUF *rval;
SHARED_BUF *sbuf; SHARED_BUF *sbuf;
size_t sbuf_size = sizeof(SHARED_BUF) + (size ? size - 1 : 0);
/* Allocate the buffer header */ /* Allocate the buffer header */
if ((rval = (GWBUF *)MXS_MALLOC(sizeof(GWBUF))) == NULL) if ((rval = (GWBUF *)MXS_MALLOC(sizeof(GWBUF))) == NULL)
@ -63,27 +64,19 @@ gwbuf_alloc(unsigned int size)
} }
/* Allocate the shared data buffer */ /* Allocate the shared data buffer */
if ((sbuf = (SHARED_BUF *)MXS_MALLOC(sizeof(SHARED_BUF))) == NULL) if ((sbuf = (SHARED_BUF *)MXS_MALLOC(sbuf_size)) == NULL)
{ {
MXS_FREE(rval); MXS_FREE(rval);
rval = NULL; rval = NULL;
goto retblock; goto retblock;
} }
/* Allocate the space for the actual data */
if ((sbuf->data = (unsigned char *)MXS_MALLOC(size)) == NULL)
{
MXS_FREE(rval);
MXS_FREE(sbuf);
rval = NULL;
goto retblock;
}
sbuf->refcount = 1; sbuf->refcount = 1;
sbuf->info = GWBUF_INFO_NONE; sbuf->info = GWBUF_INFO_NONE;
sbuf->bufobj = NULL; sbuf->bufobj = NULL;
spinlock_init(&rval->gwbuf_lock); spinlock_init(&rval->gwbuf_lock);
rval->start = sbuf->data; rval->start = &sbuf->data;
rval->end = (void *)((char *)rval->start + size); rval->end = (void *)((char *)rval->start + size);
rval->sbuf = sbuf; rval->sbuf = sbuf;
rval->next = NULL; rval->next = NULL;
@ -262,7 +255,6 @@ gwbuf_free_one(GWBUF *buf)
bo = gwbuf_remove_buffer_object(buf, bo); bo = gwbuf_remove_buffer_object(buf, bo);
} }
MXS_FREE(buf->sbuf->data);
MXS_FREE(buf->sbuf); MXS_FREE(buf->sbuf);
} }