[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <b4b58edd-b317-6319-1306-7345aa0062b8@virtuozzo.com>
Date: Wed, 8 Aug 2018 19:30:13 +0300
From: Kirill Tkhai <ktkhai@...tuozzo.com>
To: Josh Triplett <josh@...htriplett.org>
Cc: Michal Hocko <mhocko@...nel.org>, akpm@...ux-foundation.org,
gregkh@...uxfoundation.org, rafael@...nel.org,
viro@...iv.linux.org.uk, darrick.wong@...cle.com,
paulmck@...ux.vnet.ibm.com, rostedt@...dmis.org,
mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
hughd@...gle.com, shuah@...nel.org, robh@...nel.org,
ulf.hansson@...aro.org, aspriel@...il.com,
vivek.gautam@...eaurora.org, robin.murphy@....com, joe@...ches.com,
heikki.krogerus@...ux.intel.com, sfr@...b.auug.org.au,
vdavydov.dev@...il.com, chris@...is-wilson.co.uk,
penguin-kernel@...ove.SAKURA.ne.jp, aryabinin@...tuozzo.com,
willy@...radead.org, ying.huang@...el.com, shakeelb@...gle.com,
jbacik@...com, mingo@...nel.org, mhiramat@...nel.org,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org
Subject: Re: [PATCH RFC 01/10] rcu: Make CONFIG_SRCU unconditionally enabled
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?
Powered by blists - more mailing lists