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From: Vasily Averin <vvs@openvz.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: YoPOhRctb8wwbmY5@carbon, Shakeel Butt <shakeelb@google.com>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Vlastimil Babka <vbabka@suse.cz>,
	Matthew Wilcox <willy@infradead.org>,
	Hyeonggon Yoo <42.hyeyoo@gmail.com>,
	Muchun Song <songmuchun@bytedance.com>,
	kernel@openvz.org, linux-kernel@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	David Rientjes <rientjes@google.com>,
	Pekka Enberg <penberg@kernel.org>,
	Christoph Lameter <cl@linux.com>, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH v3] tracing: add 'accounted' entry into output of allocation tracepoints
Date: Thu, 19 May 2022 14:35:46 +0300	[thread overview]
Message-ID: <b728f944-e3ae-cdb6-5f02-2fb21466b2fb@openvz.org> (raw)
In-Reply-To: <20220518160447.20a7b96f@gandalf.local.home>

On 5/18/22 23:04, Steven Rostedt wrote:
> On Wed, 18 May 2022 09:24:51 +0300
> Vasily Averin <vvs@openvz.org> wrote:
> 
> FYI, the subject should be something like: mm/tracing:
> Because "tracing:" is reserved for tracing infrastructure updates.

Thank you for noticing.

>> @@ -33,42 +35,46 @@ DECLARE_EVENT_CLASS(kmem_alloc,
>>  		__entry->bytes_req	= bytes_req;
>>  		__entry->bytes_alloc	= bytes_alloc;
>>  		__entry->gfp_flags	= (__force unsigned long)gfp_flags;
>> +		__entry->accounted	= (gfp_flags & __GFP_ACCOUNT) ||
>> +					  (s && s->flags & SLAB_ACCOUNT);
> 
> Now you could make this even faster in the fast path and save just the
> s->flags.
> 
> 	__entry->sflags = s ? s->flags : 0;
> 
>>  	),
>>  
>> -	TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s",
>> +	TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s accounted=%s",
>>  		(void *)__entry->call_site,
>>  		__entry->ptr,
>>  		__entry->bytes_req,
>>  		__entry->bytes_alloc,
>> -		show_gfp_flags(__entry->gfp_flags))
>> +		show_gfp_flags(__entry->gfp_flags),
>> +		__entry->accounted ? "true" : "false")
> 
> And then have: "accounted=%s":
> 
> 		(__entry->gfp_flags & __GFP_ACCOUNT) ||
> 		(__entry->sflags & SLAB_ACCOUNT) ? "true" : "false"

Unfortunately this returns back sparse warnings about bitwise gfp_t and slab_flags_t casts.
Could you please explain why your variant is faster?

Thank you,
	Vasily Averin

WARNING: multiple messages have this Message-ID (diff)
From: Vasily Averin <vvs@openvz.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: YoPOhRctb8wwbmY5@carbon.kvack.org,
	Shakeel Butt <shakeelb@google.com>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Vlastimil Babka <vbabka@suse.cz>,
	Matthew Wilcox <willy@infradead.org>,
	Hyeonggon Yoo <42.hyeyoo@gmail.com>,
	Muchun Song <songmuchun@bytedance.com>,
	kernel@openvz.org, linux-kernel@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	David Rientjes <rientjes@google.com>,
	Pekka Enberg <penberg@kernel.org>,
	Christoph Lameter <cl@linux.com>, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH v3] tracing: add 'accounted' entry into output of allocation tracepoints
Date: Thu, 19 May 2022 14:35:46 +0300	[thread overview]
Message-ID: <b728f944-e3ae-cdb6-5f02-2fb21466b2fb@openvz.org> (raw)
In-Reply-To: <20220518160447.20a7b96f@gandalf.local.home>

On 5/18/22 23:04, Steven Rostedt wrote:
> On Wed, 18 May 2022 09:24:51 +0300
> Vasily Averin <vvs@openvz.org> wrote:
> 
> FYI, the subject should be something like: mm/tracing:
> Because "tracing:" is reserved for tracing infrastructure updates.

Thank you for noticing.

>> @@ -33,42 +35,46 @@ DECLARE_EVENT_CLASS(kmem_alloc,
>>  		__entry->bytes_req	= bytes_req;
>>  		__entry->bytes_alloc	= bytes_alloc;
>>  		__entry->gfp_flags	= (__force unsigned long)gfp_flags;
>> +		__entry->accounted	= (gfp_flags & __GFP_ACCOUNT) ||
>> +					  (s && s->flags & SLAB_ACCOUNT);
> 
> Now you could make this even faster in the fast path and save just the
> s->flags.
> 
> 	__entry->sflags = s ? s->flags : 0;
> 
>>  	),
>>  
>> -	TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s",
>> +	TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s accounted=%s",
>>  		(void *)__entry->call_site,
>>  		__entry->ptr,
>>  		__entry->bytes_req,
>>  		__entry->bytes_alloc,
>> -		show_gfp_flags(__entry->gfp_flags))
>> +		show_gfp_flags(__entry->gfp_flags),
>> +		__entry->accounted ? "true" : "false")
> 
> And then have: "accounted=%s":
> 
> 		(__entry->gfp_flags & __GFP_ACCOUNT) ||
> 		(__entry->sflags & SLAB_ACCOUNT) ? "true" : "false"

Unfortunately this returns back sparse warnings about bitwise gfp_t and slab_flags_t casts.
Could you please explain why your variant is faster?

Thank you,
	Vasily Averin


  reply	other threads:[~2022-05-19 11:36 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-18  6:24 [PATCH v3] tracing: add 'accounted' entry into output of allocation tracepoints Vasily Averin
2022-05-18 15:09 ` Shakeel Butt
2022-05-18 15:45 ` Vasily Averin
2022-05-18 20:04 ` Steven Rostedt
2022-05-18 20:04   ` Steven Rostedt
2022-05-19 11:35   ` Vasily Averin [this message]
2022-05-19 11:35     ` Vasily Averin
2022-05-19 14:03     ` Steven Rostedt
2022-05-19 14:03       ` Steven Rostedt
2022-05-19 16:29       ` Vasily Averin
2022-05-19 16:29         ` Vasily Averin
2022-05-19 16:32         ` Steven Rostedt
2022-05-19 16:32           ` Steven Rostedt
2022-05-21 18:32           ` Vasily Averin
2022-05-21 18:32             ` Vasily Averin
2022-05-21 18:36             ` [PATCH v4] " Vasily Averin
2022-05-22  3:51               ` Hyeonggon Yoo
2022-05-22  4:33                 ` Vasily Averin
2022-05-22  5:19                   ` Hyeonggon Yoo
2022-05-22  5:42                     ` Shakeel Butt
2022-05-22 18:53                     ` Vasily Averin
2022-05-22 20:09                   ` Steven Rostedt
2022-05-23  4:03                     ` Vasily Averin
2022-05-23 13:12               ` Vlastimil Babka
2022-05-30  7:47                 ` [PATCH v5] " Vasily Averin
2022-05-30  8:25                   ` Muchun Song
2022-05-31 11:46                   ` Hyeonggon Yoo
2022-05-31 16:58                     ` Vasily Averin
2022-06-03  3:21                       ` [PATCH mm v6] mm/tracing: " Vasily Averin
2022-06-03  3:21                         ` Vasily Averin
2022-06-15  9:41                         ` Vlastimil Babka
2022-06-15  9:41                           ` Vlastimil Babka
2022-05-25  1:34               ` [PATCH v4] tracing: " Roman Gushchin
2022-05-25  7:33               ` Hyeonggon Yoo
2022-05-25  8:24                 ` Vasily Averin

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