From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: Josh Triplett <josh@joshtriplett.org>
Cc: Michal Hocko <mhocko@kernel.org>,
akpm@linux-foundation.org, gregkh@linuxfoundation.org,
rafael@kernel.org, viro@zeniv.linux.org.uk,
darrick.wong@oracle.com, paulmck@linux.vnet.ibm.com,
rostedt@goodmis.org, mathieu.desnoyers@efficios.com,
jiangshanlai@gmail.com, hughd@google.com, shuah@kernel.org,
robh@kernel.org, ulf.hansson@linaro.org, aspriel@gmail.com,
vivek.gautam@codeaurora.org, robin.murphy@arm.com,
joe@perches.com, heikki.krogerus@linux.intel.com,
sfr@canb.auug.org.au, vdavydov.dev@gmail.com,
chris@chris-wilson.co.uk, penguin-kernel@I-love.SAKURA.ne.jp,
aryabinin@virtuozzo.com, willy@infradead.org,
ying.huang@intel.com, shakeelb@google.com, jbacik@fb.com,
mingo@kernel.org, mhiramat@kernel.org,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH RFC 01/10] rcu: Make CONFIG_SRCU unconditionally enabled
Date: Wed, 8 Aug 2018 19:30:13 +0300 [thread overview]
Message-ID: <b4b58edd-b317-6319-1306-7345aa0062b8@virtuozzo.com> (raw)
In-Reply-To: <f32ab99a-de28-b140-a7d0-027073055728@virtuozzo.com>
On 08.08.2018 19:23, Kirill Tkhai wrote:
> On 08.08.2018 19:13, Josh Triplett wrote:
>> On Wed, Aug 08, 2018 at 01:17:44PM +0300, Kirill Tkhai wrote:
>>> On 08.08.2018 10:20, Michal Hocko wrote:
>>>> On Tue 07-08-18 18:37:36, Kirill Tkhai wrote:
>>>>> This patch kills all CONFIG_SRCU defines and
>>>>> the code under !CONFIG_SRCU.
>>>>
>>>> The last time somebody tried to do this there was a pushback due to
>>>> kernel tinyfication. So this should really give some numbers about the
>>>> code size increase. Also why can't we make this depend on MMU. Is
>>>> anybody else than the reclaim asking for unconditional SRCU usage?
>>>
>>> I don't know one. The size numbers (sparc64) are:
>>>
>>> $ size image.srcu.disabled
>>> text data bss dec hex filename
>>> 5117546 8030506 1968104 15116156 e6a77c image.srcu.disabled
>>> $ size image.srcu.enabled
>>> text data bss dec hex filename
>>> 5126175 8064346 1968104 15158625 e74d61 image.srcu.enabled
>>> The difference is: 15158625-15116156 = 42469 ~41Kb
>>
>> 41k is a *substantial* size increase. However, can you compare
>> tinyconfig with and without this patch? That may have a smaller change.
>
> $ size image.srcu.disabled
> text data bss dec hex filename
> 1105900 195456 63232 1364588 14d26c image.srcu.disabled
>
> $ size image.srcu.enabled
> text data bss dec hex filename
> 1106960 195528 63232 1365720 14d6d8 image.srcu.enabled
>
> 1365720-1364588 = 1132 ~ 1Kb
1Kb is not huge size. It looks as not a big price for writing generic code
for only case (now some places have CONFIG_SRCU and !CONFIG_SRCU variants,
e.g. drivers/base/core.c). What do you think?
next prev parent reply other threads:[~2018-08-08 16:30 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 15:37 [PATCH RFC 00/10] Introduce lockless shrink_slab() Kirill Tkhai
2018-08-07 15:37 ` [PATCH RFC 01/10] rcu: Make CONFIG_SRCU unconditionally enabled Kirill Tkhai
2018-08-08 0:55 ` Steven Rostedt
2018-08-08 1:05 ` Stephen Rothwell
2018-08-08 9:46 ` Kirill Tkhai
2018-08-08 1:08 ` Stephen Rothwell
2018-08-08 9:59 ` Kirill Tkhai
2018-08-08 11:04 ` Stephen Rothwell
2018-08-08 7:20 ` Michal Hocko
2018-08-08 10:17 ` Kirill Tkhai
2018-08-08 10:27 ` Michal Hocko
2018-08-08 21:31 ` Dave Chinner
2018-08-09 0:07 ` Matthew Wilcox
2018-08-09 7:45 ` Greg KH
2018-08-09 10:22 ` Kirill Tkhai
2018-08-08 16:13 ` Josh Triplett
2018-08-08 16:23 ` Kirill Tkhai
2018-08-08 16:30 ` Kirill Tkhai [this message]
2018-08-08 18:01 ` Josh Triplett
2018-08-08 23:02 ` Shakeel Butt
2018-08-08 23:09 ` Josh Triplett
2018-08-07 15:37 ` [PATCH RFC 02/10] mm: Make shrink_slab() lockless Kirill Tkhai
2018-08-08 11:51 ` Kirill Tkhai
2018-08-08 13:20 ` [PATCH RFC v2 " Kirill Tkhai
2018-08-09 7:14 ` Michal Hocko
2018-08-09 9:21 ` Kirill Tkhai
2018-08-09 10:37 ` Tetsuo Handa
2018-08-09 10:58 ` Kirill Tkhai
2018-08-09 11:23 ` Kirill Tkhai
2018-08-07 15:38 ` [PATCH RFC 03/10] mm: Convert shrinker_rwsem to mutex Kirill Tkhai
2018-08-07 15:38 ` [PATCH RFC 04/10] mm: Split unregister_shrinker() Kirill Tkhai
2018-08-07 15:38 ` [PATCH RFC 05/10] fs: Move list_lru_destroy() to destroy_super_work() Kirill Tkhai
2018-08-07 15:38 ` [PATCH RFC 06/10] fs: Shrink only (SB_ACTIVE|SB_BORN) superblocks in super_cache_scan() Kirill Tkhai
2018-08-07 15:38 ` [PATCH RFC 07/10] fs: Introduce struct super_operations::destroy_super() callback Kirill Tkhai
2018-08-07 15:39 ` [PATCH RFC 08/10] xfs: Introduce xfs_fs_destroy_super() Kirill Tkhai
2018-08-07 15:39 ` [PATCH RFC 09/10] shmem: Implement shmem_destroy_super() Kirill Tkhai
2018-08-07 15:39 ` [PATCH RFC 10/10] fs: Use unregister_shrinker_delayed_{initiate, finalize} for super_block shrinker Kirill Tkhai
2018-08-08 1:12 ` [PATCH RFC 00/10] Introduce lockless shrink_slab() Stephen Rothwell
2018-08-08 5:39 ` Shakeel Butt
2018-08-08 10:18 ` Kirill Tkhai
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