[lustre-devel] [PATCH 11/21] lustre: cl_object: remove vestigial debugging.

[NeilBrown]

On Mon, Feb 11 2019, James Simmons wrote:

>> cl_env_inc() and cl_env_dec() don't do anything,
>> so discard them.
>
> I don't know about this one. I saw Andreas response as well. 
> So this was apart of "LU-744 obdclass: revise stats for cl_object cache"
> In the end it was turned off by default in the OpenSFS branch since it
> made performance take a hit. To enable in OpenSFS branch you have to run
> ./configure --enable-pgstate-track. We have a few like this for Lustre so
> I was going to bring this up. Do we want to remove this work for both the
> upstream client as well as OpenSFS tree or properly implement this by
> making it a Kconfig option when CONFIG_LUSTRE_DEBUG_EXPENSIVE_CHECK is
> enabled? Its just a matter of porting OpenSFS commit 
> 5cae09a2409dcd396a1ee7be1eca7d3bbf77365e
>
> What do you think?

How useful are these stats?
Stats that are never compiled in aren't likely to tell you much :-)

Has any thought been given to per-cpu stats counting?  That seems to be
the preferred approach for high-frequency accounting.

I think having a CONFIG option to enable expensive consistency checks is
a good idea - developers will enable it when they don't care about
performance.
Having a CONFIG option for expensive performance stats seems... weird.
Who would use it, and how meaningful would the number be?

NeilBrown


>
>> Signed-off-by: NeilBrown <neilb at suse.com>
>> ---
>>  drivers/staging/lustre/lustre/obdclass/cl_object.c |   15 ---------------
>>  1 file changed, 15 deletions(-)
>> 
>> diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c
>> index d71a680660da..1e704078664e 100644
>> --- a/drivers/staging/lustre/lustre/obdclass/cl_object.c
>> +++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c
>> @@ -565,14 +565,6 @@ struct cl_env {
>>  	void		       *ce_debug;
>>  };
>>  
>> -static void cl_env_inc(enum cache_stats_item item)
>> -{
>> -}
>> -
>> -static void cl_env_dec(enum cache_stats_item item)
>> -{
>> -}
>> -
>>  static void cl_env_init0(struct cl_env *cle, void *debug)
>>  {
>>  	LASSERT(cle->ce_ref == 0);
>> @@ -581,7 +573,6 @@ static void cl_env_init0(struct cl_env *cle, void *debug)
>>  
>>  	cle->ce_ref = 1;
>>  	cle->ce_debug = debug;
>> -	cl_env_inc(CS_busy);
>>  }
>>  
>>  static struct lu_env *cl_env_new(u32 ctx_tags, u32 ses_tags, void *debug)
>> @@ -611,9 +602,6 @@ static struct lu_env *cl_env_new(u32 ctx_tags, u32 ses_tags, void *debug)
>>  		if (rc != 0) {
>>  			kmem_cache_free(cl_env_kmem, cle);
>>  			env = ERR_PTR(rc);
>> -		} else {
>> -			cl_env_inc(CS_create);
>> -			cl_env_inc(CS_total);
>>  		}
>>  	} else {
>>  		env = ERR_PTR(-ENOMEM);
>> @@ -623,7 +611,6 @@ static struct lu_env *cl_env_new(u32 ctx_tags, u32 ses_tags, void *debug)
>>  
>>  static void cl_env_fini(struct cl_env *cle)
>>  {
>> -	cl_env_dec(CS_total);
>>  	lu_context_fini(&cle->ce_lu.le_ctx);
>>  	lu_context_fini(&cle->ce_ses);
>>  	kmem_cache_free(cl_env_kmem, cle);
>> @@ -782,7 +769,6 @@ void cl_env_put(struct lu_env *env, u16 *refcheck)
>>  	if (--cle->ce_ref == 0) {
>>  		int cpu = get_cpu();
>>  
>> -		cl_env_dec(CS_busy);
>>  		cle->ce_debug = NULL;
>>  		cl_env_exit(cle);
>>  		/*
>> @@ -903,7 +889,6 @@ void cl_env_percpu_put(struct lu_env *env)
>>  	cle->ce_ref--;
>>  	LASSERT(cle->ce_ref == 0);
>>  
>> -	cl_env_dec(CS_busy);
>>  	cle->ce_debug = NULL;
>>  
>>  	put_cpu();
>> 
>> 
>> 
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