From: Peter Zijlstra <peterz@infradead.org>
To: lkp@lists.01.org
Subject: Re: [PATCH] objtool, static_call: Don't emit static_call_site for .exit.text
Date: Thu, 18 Mar 2021 09:30:18 +0100 [thread overview]
Message-ID: <YFMPmkMoae5cRzh+@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YFMIcWIbk0aN30NY@hirez.programming.kicks-ass.net>
[-- Attachment #1: Type: text/plain, Size: 1139 bytes --]
On Thu, Mar 18, 2021 at 08:59:45AM +0100, Peter Zijlstra wrote:
> On Wed, Mar 17, 2021 at 07:02:12PM -0500, Josh Poimboeuf wrote:
> > On Wed, Mar 17, 2021 at 01:45:57PM +0100, Peter Zijlstra wrote:
> > > arguably it simply isn't a good idea to use static_call() in __exit
> > > code anyway, since module unload is never a performance critical path.
> >
> > Couldn't you make the same argument about __init functions, which are
> > allowed to do static calls?
>
> I suppose we could indeed make that argument. Much of that code was
> copied from jump_label without much consideration. And I now I suppose
> I'll have to consider jump_label in __exit too :/
>
> > We might consider a STATIC_CALL_SITE_EXIT flag, but I suppose we've run
> > out of flag space.
>
> Yeah, we're definitely short on flags. Let me try and figure out when
> exactly it's all discarded.
Ha!, x86 stuffs .exit.text in [__init_begin, __init_end) and it is
discarded right along with initmem.
But that means it should match init and be tagged init and all *should*
work, but somehow it doesn't... clearly I'm missing something again
ARGH!
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Sumit Garg <sumit.garg@linaro.org>,
Oliver Sang <oliver.sang@intel.com>,
jbaron@akamai.com, lkp@lists.01.org,
kbuild test robot <lkp@intel.com>,
Jarkko Sakkinen <jarkko@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] objtool,static_call: Don't emit static_call_site for .exit.text
Date: Thu, 18 Mar 2021 09:30:18 +0100 [thread overview]
Message-ID: <YFMPmkMoae5cRzh+@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YFMIcWIbk0aN30NY@hirez.programming.kicks-ass.net>
On Thu, Mar 18, 2021 at 08:59:45AM +0100, Peter Zijlstra wrote:
> On Wed, Mar 17, 2021 at 07:02:12PM -0500, Josh Poimboeuf wrote:
> > On Wed, Mar 17, 2021 at 01:45:57PM +0100, Peter Zijlstra wrote:
> > > arguably it simply isn't a good idea to use static_call() in __exit
> > > code anyway, since module unload is never a performance critical path.
> >
> > Couldn't you make the same argument about __init functions, which are
> > allowed to do static calls?
>
> I suppose we could indeed make that argument. Much of that code was
> copied from jump_label without much consideration. And I now I suppose
> I'll have to consider jump_label in __exit too :/
>
> > We might consider a STATIC_CALL_SITE_EXIT flag, but I suppose we've run
> > out of flag space.
>
> Yeah, we're definitely short on flags. Let me try and figure out when
> exactly it's all discarded.
Ha!, x86 stuffs .exit.text in [__init_begin, __init_end) and it is
discarded right along with initmem.
But that means it should match init and be tagged init and all *should*
work, but somehow it doesn't... clearly I'm missing something again
ARGH!
next prev parent reply other threads:[~2021-03-18 8:30 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-15 14:23 [KEYS] 4a00e5e212: WARNING:at_arch/x86/kernel/static_call.c:#__static_call_validate kernel test robot
2021-03-16 8:04 ` Sumit Garg
2021-03-17 3:01 ` Oliver Sang
2021-03-17 7:25 ` Sumit Garg
2021-03-17 8:41 ` Peter Zijlstra
2021-03-17 8:59 ` Peter Zijlstra
2021-03-17 9:02 ` Peter Zijlstra
2021-03-17 11:55 ` Sumit Garg
2021-03-17 12:45 ` [PATCH] objtool, static_call: Don't emit static_call_site for .exit.text Peter Zijlstra
2021-03-17 12:45 ` [PATCH] objtool,static_call: " Peter Zijlstra
2021-03-17 13:37 ` [PATCH] objtool, static_call: " Sumit Garg
2021-03-17 13:37 ` [PATCH] objtool,static_call: " Sumit Garg
2021-03-17 21:55 ` [PATCH] objtool, static_call: " Jarkko Sakkinen
2021-03-17 21:55 ` [PATCH] objtool,static_call: " Jarkko Sakkinen
2021-03-18 4:42 ` [PATCH] objtool, static_call: " Sumit Garg
2021-03-18 4:42 ` [PATCH] objtool,static_call: " Sumit Garg
2021-03-17 21:01 ` [PATCH] objtool, static_call: " Jarkko Sakkinen
2021-03-17 21:01 ` [PATCH] objtool,static_call: " Jarkko Sakkinen
2021-03-18 0:02 ` [PATCH] objtool, static_call: " Josh Poimboeuf
2021-03-18 0:02 ` [PATCH] objtool,static_call: " Josh Poimboeuf
2021-03-18 7:59 ` [PATCH] objtool, static_call: " Peter Zijlstra
2021-03-18 7:59 ` [PATCH] objtool,static_call: " Peter Zijlstra
2021-03-18 8:30 ` Peter Zijlstra [this message]
2021-03-18 8:30 ` Peter Zijlstra
2021-03-18 8:47 ` [PATCH] objtool, static_call: " Peter Zijlstra
2021-03-18 8:47 ` [PATCH] objtool,static_call: " Peter Zijlstra
2021-03-17 21:00 ` [KEYS] 4a00e5e212: WARNING:at_arch/x86/kernel/static_call.c:#__static_call_validate Jarkko Sakkinen
2021-03-18 10:25 ` Peter Zijlstra
2021-03-18 11:03 ` Sumit Garg
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