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From: Vlastimil Babka <vbabka@suse.cz>
To: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Joe Perches <joe@perches.com>,
	Vasily Averin <vasily.averin@linux.dev>,
	Matthew WilCox <willy@infradead.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v3 08/15] mm/slab_common: kmalloc_node: pass large requests to page allocator
Date: Tue, 2 Aug 2022 11:32:41 +0200	[thread overview]
Message-ID: <321b8b3e-9d06-b01c-d871-1f7ca35ce91e@suse.cz> (raw)
In-Reply-To: <Yujnihj5YVPP2LjA@hyeyoo>

On 8/2/22 10:59, Hyeonggon Yoo wrote:
> On Mon, Aug 01, 2022 at 04:44:22PM +0200, Vlastimil Babka wrote:
>> 
> 
> Yeah, uninlining __kmalloc_large_node saves hundreds of bytes.
> And the diff below looks good to me.
> 
> By The Way, do you have opinions on inlining slab_alloc_node()?
> (Looks like similar topic?)
> 
> AFAIK slab_alloc_node() is inlined in:
>         kmem_cache_alloc()
>         kmem_cache_alloc_node()
>         kmem_cache_alloc_lru()
>         kmem_cache_alloc_trace()
>         kmem_cache_alloc_node_trace()
>         __kmem_cache_alloc_node()
> 
> This is what I get after simply dropping __always_inline in slab_alloc_node:
> 
> add/remove: 1/1 grow/shrink: 3/6 up/down: 1911/-5275 (-3364)
> Function                                     old     new   delta
> slab_alloc_node                                -    1356   +1356
> sysfs_slab_alias                             134     327    +193
> slab_memory_callback                         528     717    +189
> __kmem_cache_create                         1325    1498    +173
> __slab_alloc.constprop                       135       -    -135
> kmem_cache_alloc_trace                       909     196    -713
> kmem_cache_alloc                             937     191    -746
> kmem_cache_alloc_node_trace                 1020     200    -820
> __kmem_cache_alloc_node                      862      19    -843
> kmem_cache_alloc_node                       1046     189    -857
> kmem_cache_alloc_lru                        1348     187   -1161
> Total: Before=32011183, After=32007819, chg -0.01%
> 
> So 3.28kB is cost of eliminating function call overhead in the 
> fastpath.
> 
> This is tradeoff between function call overhead and
> instruction cache usage...

We can investigate this aftewards, with proper measurements etc. I think
it's more sensitive than kmalloc_large_node.


  reply	other threads:[~2022-08-02  9:32 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-12 13:39 [PATCH v3 00/15] common kmalloc v3 Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 1/15] mm/slab: move NUMA-related code to __do_cache_alloc() Hyeonggon Yoo
2022-07-12 14:29   ` Christoph Lameter
2022-07-13  9:39     ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 2/15] mm/slab: cleanup slab_alloc() and slab_alloc_node() Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 03/15] mm/slab_common: remove CONFIG_NUMA ifdefs for common kmalloc functions Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 04/15] mm/slab_common: cleanup kmalloc_track_caller() Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 05/15] mm/sl[au]b: factor out __do_kmalloc_node() Hyeonggon Yoo
2022-07-28 14:45   ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 06/15] mm/slab_common: fold kmalloc_order_trace() into kmalloc_large() Hyeonggon Yoo
2022-07-28 15:23   ` Vlastimil Babka
2022-08-01 13:26     ` Hyeonggon Yoo
2022-08-01 13:36       ` Vlastimil Babka
2022-08-02  2:54         ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 07/15] mm/slub: move kmalloc_large_node() to slab_common.c Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH v3 08/15] mm/slab_common: kmalloc_node: pass large requests to page allocator Hyeonggon Yoo
2022-07-28 16:09   ` Vlastimil Babka
2022-08-01 14:37     ` Hyeonggon Yoo
2022-08-01 14:44       ` Vlastimil Babka
2022-08-02  8:59         ` Hyeonggon Yoo
2022-08-02  9:32           ` Vlastimil Babka [this message]
2022-07-12 13:39 ` [PATCH v3 09/15] mm/slab_common: cleanup kmalloc_large() Hyeonggon Yoo
2022-07-28 16:13   ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 10/15] mm/slab: kmalloc: pass requests larger than order-1 page to page allocator Hyeonggon Yoo
2022-07-28 16:25   ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 11/15] mm/sl[au]b: introduce common alloc/free functions without tracepoint Hyeonggon Yoo
2022-07-29  9:49   ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 12/15] mm/sl[au]b: generalize kmalloc subsystem Hyeonggon Yoo
2022-07-29 10:25   ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH v3 13/15] mm/slab_common: unify NUMA and UMA version of tracepoints Hyeonggon Yoo
2022-07-29 10:52   ` Vlastimil Babka
2022-07-12 13:39 ` [PATCH 14/16] mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using Hyeonggon Yoo
2022-07-29 11:23   ` Vlastimil Babka
2022-08-02  9:22     ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH 15/16] mm/slab_common: move definition of __ksize() to mm/slab.h Hyeonggon Yoo
2022-07-29 11:47   ` Vlastimil Babka
2022-08-02  9:25     ` Hyeonggon Yoo
2022-07-12 13:39 ` [PATCH 16/16] mm/sl[au]b: check if large object is valid in __ksize() Hyeonggon Yoo
2022-07-12 15:13   ` Christoph Lameter
2022-07-13  9:25     ` Hyeonggon Yoo
2022-07-13 10:07       ` Christoph Lameter
2022-07-13 10:33         ` Marco Elver
2022-07-14  9:15           ` Christoph Lameter
2022-07-14 10:30             ` Marco Elver
2022-07-20 10:05               ` Hyeonggon Yoo
2022-07-29 11:50   ` Vlastimil Babka
2022-07-29 15:08 ` [PATCH v3 00/15] common kmalloc v3 Vlastimil Babka
2022-08-14 10:06   ` Hyeonggon Yoo
2022-08-15 12:59     ` Vlastimil Babka

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