Re: [PATCH v4 2/9] liblockdep: Wrap kernel/lockdep.c to allow usage from userspace

[Sasha Levin <sasha.levin@oracle.com>]

On 05/22/2013 05:17 AM, Peter Zijlstra wrote:
> On Wed, May 15, 2013 at 11:15:34PM -0400, Sasha Levin wrote:
>> --- /dev/null
>> +++ b/tools/lib/lockdep/uinclude/linux/lockdep.h
>> @@ -0,0 +1,55 @@
>> +#ifndef _LIBLOCKDEP_LOCKDEP_H_
>> +#define _LIBLOCKDEP_LOCKDEP_H_
>> +
>> +#include <sys/prctl.h>
>> +#include <sys/syscall.h>
>> +#include <string.h>
>> +#include <limits.h>
>> +#include <linux/utsname.h>
>> +
>> +
>> +#define MAX_LOCK_DEPTH 2000UL
>> +
>> +#include "../../../include/linux/lockdep.h"
>> +
>> +struct task_struct {
>> +	u64 curr_chain_key;
>> +	int lockdep_depth;
>> +	unsigned int lockdep_recursion;
>> +	struct held_lock held_locks[MAX_LOCK_DEPTH];
>> +	gfp_t lockdep_reclaim_gfp;
>> +	int pid;
>> +	char comm[17];
>> +};
> 
> Whee that's a totally awesome MAX_LOCK_DEPTH.. :-)
> 
> Should we not also extend the other static allocations, or have you not
> yet ran into them? I would suspect that without proper classes we're
> bound to run out of class and link storage quite quickly.

I've changed MAX_LOCK_DEPTH just because I've actually hit it. I haven't
got around to hitting anything else, but I guess we could preemptively
send them hight.

What values would make sense here?


Thanks,
Sasha