hcq/MaxScale
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Added back read and write mutex to dcb. Locks are acquired in poll.c before calling call-back functions. Additional locks efficiently hide memory corruption issue, which appears when readconn router is used without using those mutexes, with multiple parallel maxscale threads and intensive load.

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This commit is contained in:
vraatikka 2013-11-20 17:23:04 +02:00
parent 35d34862b9
commit a30e2ab29b
3 changed files with 39 additions and 1 deletions
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6
server/core/dcb.c
View File

@ -106,6 +106,12 @@ if ((rval = calloc(1, sizeof(DCB))) == NULL)
rval->dcb_chk_tail = CHK_NUM_DCB;
#endif
rval->dcb_role = role;
#if 1
simple_mutex_init(&rval->dcb_write_lock, "DCB write mutex");
simple_mutex_init(&rval->dcb_read_lock, "DCB read mutex");
rval->dcb_write_active = false;
rval->dcb_read_active = false;
#endif
spinlock_init(&rval->dcb_initlock);
spinlock_init(&rval->writeqlock);
spinlock_init(&rval->delayqlock);

28
server/core/poll.c
View File

@ -406,10 +406,24 @@ poll_waitevents(void *arg)
eno = gw_getsockerrno(dcb->fd);
if (eno == 0) {
#if 1
simple_mutex_lock(
&dcb->dcb_write_lock,
true);
ss_info_dassert(
!dcb->dcb_write_active,
"Write already active");
dcb->dcb_write_active = TRUE;
#endif
atomic_add(
&pollStats.n_write,
&pollStats.n_write,
1);
dcb->func.write_ready(dcb);
#if 1
dcb->dcb_write_active = FALSE;
simple_mutex_unlock(
&dcb->dcb_write_lock);
#endif
} else {
skygw_log_write(
LOGFILE_DEBUG,
@ -425,6 +439,13 @@ poll_waitevents(void *arg)
}
if (ev & EPOLLIN)
{
#if 1
simple_mutex_lock(&dcb->dcb_read_lock,
true);
ss_info_dassert(!dcb->dcb_read_active,
"Read already active");
dcb->dcb_read_active = TRUE;
#endif
if (dcb->state == DCB_STATE_LISTENING)
{
skygw_log_write(
@ -449,6 +470,11 @@ poll_waitevents(void *arg)
atomic_add(&pollStats.n_read, 1);
dcb->func.read(dcb);
}
#if 1
dcb->dcb_read_active = FALSE;
simple_mutex_unlock(
&dcb->dcb_read_lock);
#endif
}
} /**< for */
no_op = FALSE;

6
server/include/dcb.h
View File

@ -156,6 +156,12 @@ typedef struct dcb {
#endif
dcb_role_t dcb_role;
SPINLOCK dcb_initlock;
#if 1
simple_mutex_t dcb_read_lock;
simple_mutex_t dcb_write_lock;
bool dcb_read_active;
bool dcb_write_active;
#endif
int fd; /**< The descriptor */
dcb_state_t state; /**< Current descriptor state */
char *remote; /**< Address of remote end */