mysqld [3.2.23] hangs when key_buffer ~256MB on [2.4.2-ac28+]

mysqld [3.2.23] hangs when key_buffer ~256MB on [2.4.2-ac28+]

[Vibol Hou]

I initially upgraded my kernel from 2.4.2-ac5 to 2.4.3 and the first thing I
noticed was that mysqld was stuck.  Killing it left it hanging in a D state.
Then I tried 2.4.2-ac28 (which I am using now), and the got the same result.

My key_buffer was set to 256MB, so I figured maybe it was something to do
with memory usage so I lowered that figured to 128MB and restarted the
system to clear the D state procs.  Everything works fine now.  2.4.2-ac5
did not have issues with the larger key_buffer.

Can anyone reproduce this problem?

--
Vibol Hou
KhmerConnection, http://khmer.cc
"Connecting Cambodian Minds, Art, and Culture"

Re: mysqld [3.2.23] hangs when key_buffer ~256MB on [2.4.2-ac28+]

[Alan Cox]

> I initially upgraded my kernel from 2.4.2-ac5 to 2.4.3 and the first thing I
> noticed was that mysqld was stuck.  Killing it left it hanging in a D state.
> Then I tried 2.4.2-ac28 (which I am using now), and the got the same result.

I'd expect that bit. 2.4.2-ac28 basically has the same new rwlock VM and
behaviour as 2.4.3pre8. What would be really useful to know is if anyone can
duplicate the problem non x86

> Can anyone reproduce this problem?

Yes

Re: mysqld [3.2.23] hangs when key_buffer ~256MB on [2.4.2-ac28+]

[Andrew Morton]

Alan Cox wrote:
> 
> > I initially upgraded my kernel from 2.4.2-ac5 to 2.4.3 and the first thing I
> > noticed was that mysqld was stuck.  Killing it left it hanging in a D state.
> > Then I tried 2.4.2-ac28 (which I am using now), and the got the same result.
> 
> I'd expect that bit. 2.4.2-ac28 basically has the same new rwlock VM and
> behaviour as 2.4.3pre8. What would be really useful to know is if anyone can
> duplicate the problem non x86
> 
> > Can anyone reproduce this problem?
> 
> Yes

Untested patch:


--- semaphore.c.orig    Wed Apr  4 12:54:30 2001
+++ semaphore.c Wed Apr  4 12:54:58 2001
@@ -363,26 +363,26 @@
  */
 struct rw_semaphore *down_write_failed(struct rw_semaphore *sem)
 {
        struct task_struct *tsk = current;
        DECLARE_WAITQUEUE(wait, tsk);
 
        __up_write(sem);        /* this takes care of granting the lock
*/
 
-       add_wait_queue_exclusive(&sem->wait, &wait);
+       add_wait_queue_exclusive(&sem->write_bias_wait, &wait);
 
        while (atomic_read(&sem->count) < 0) {
                set_task_state(tsk, TASK_UNINTERRUPTIBLE);
                if (atomic_read(&sem->count) >= 0)
                        break;  /* we must attempt to acquire or bias
the lock */
                schedule();
        }
 
-       remove_wait_queue(&sem->wait, &wait);
+       remove_wait_queue(&sem->write_bias_wait, &wait);
        tsk->state = TASK_RUNNING;
 
        return sem;
 }
 
 asm(
 "
 .align 4

RE: mysqld [3.2.23] hangs when key_buffer ~256MB on [2.4.2-ac28+]

[Vibol Hou]

Andrew,

I've applied the patch.  The processes usually start dying within a few
minutes so it shouldn't be hard to tell if this patch is working or not.
I'll let you know what's up.

-Vibol

-----Original Message-----
From: akpm@uow.edu.au [mailto:akpm@uow.edu.au]On Behalf Of Andrew Morton
Sent: Wednesday, April 04, 2001 12:57 PM
To: Alan Cox
Cc: Vibol Hou; Linux-Kernel
Subject: Re: mysqld [3.2.23] hangs when key_buffer ~256MB on
[2.4.2-ac28+]


Alan Cox wrote:
>
> > I initially upgraded my kernel from 2.4.2-ac5 to 2.4.3 and the first
thing I
> > noticed was that mysqld was stuck.  Killing it left it hanging in a D
state.
> > Then I tried 2.4.2-ac28 (which I am using now), and the got the same
result.
>
> I'd expect that bit. 2.4.2-ac28 basically has the same new rwlock VM and
> behaviour as 2.4.3pre8. What would be really useful to know is if anyone
can
> duplicate the problem non x86
>
> > Can anyone reproduce this problem?
>
> Yes

Untested patch:


--- semaphore.c.orig    Wed Apr  4 12:54:30 2001
+++ semaphore.c Wed Apr  4 12:54:58 2001
@@ -363,26 +363,26 @@
  */
 struct rw_semaphore *down_write_failed(struct rw_semaphore *sem)
 {
        struct task_struct *tsk = current;
        DECLARE_WAITQUEUE(wait, tsk);

        __up_write(sem);        /* this takes care of granting the lock
*/

-       add_wait_queue_exclusive(&sem->wait, &wait);
+       add_wait_queue_exclusive(&sem->write_bias_wait, &wait);

        while (atomic_read(&sem->count) < 0) {
                set_task_state(tsk, TASK_UNINTERRUPTIBLE);
                if (atomic_read(&sem->count) >= 0)
                        break;  /* we must attempt to acquire or bias
the lock */
                schedule();
        }

-       remove_wait_queue(&sem->wait, &wait);
+       remove_wait_queue(&sem->write_bias_wait, &wait);
        tsk->state = TASK_RUNNING;

        return sem;
 }

 asm(
 "
 .align 4