From: Peter Zijlstra <peterz@infradead.org>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: x86@kernel.org, jpoimboe@redhat.com, jbaron@akamai.com,
rostedt@goodmis.org, ardb@kernel.org,
linux-kernel@vger.kernel.org, sumit.garg@linaro.org,
oliver.sang@intel.com, jarkko@kernel.org
Subject: Re: [PATCH 2/3] static_call: Align static_call_is_init() patching condition
Date: Mon, 22 Mar 2021 17:59:08 +0100 [thread overview]
Message-ID: <YFjM3HgyZS14x0m/@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <c4e9dfdf-c83a-3314-8c55-5b2371a56ec8@rasmusvillemoes.dk>
On Fri, Mar 19, 2021 at 03:40:46PM +0100, Rasmus Villemoes wrote:
> On 19/03/2021 15.13, Peter Zijlstra wrote:
>
> >> Dunno, probably overkill, but perhaps we could have an atomic_t (or
> >> refcount, whatever) init_ref inited to 1, with init_ref_get() doing an
> >> inc_unless_zero, and iff you get a ref, you're free to call (/patch)
> >> __init functions and access __initdata, but must do init_ref_put(), with
> >> PID1 dropping its initial ref and waiting for it to drop to 0 before
> >> doing the *free_initmem() calls.
> >
> > I'd as soon simply add another SYSTEM state. That way we don't have to
> > worry about who else looks at RUNNING for what etc..
>
> I don't understand. How would that solve the
>
> PID1 PIDX
> ok = system_state < INIT_MEM_GONE;
> system_state = INIT_MEM_GONE;
> free_initmem();
> system_state = RUNNING;
> if (ok)
> poke init mem
>
> race?
Argh, I meant to put it before SMP bringup, but then still have to run
the smp_init calls :/
N/m, you're quite right.
next prev parent reply other threads:[~2021-03-22 17:01 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 11:31 [PATCH 0/3] static_call() vs __exit fixes Peter Zijlstra
2021-03-18 11:31 ` [PATCH 1/3] static_call: Fix static_call_set_init() Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-18 11:31 ` [PATCH 2/3] static_call: Align static_call_is_init() patching condition Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-19 13:31 ` [PATCH 2/3] " Rasmus Villemoes
2021-03-19 14:13 ` Peter Zijlstra
2021-03-19 14:40 ` Rasmus Villemoes
2021-03-19 15:44 ` Rasmus Villemoes
2021-03-22 16:59 ` Peter Zijlstra [this message]
2021-03-18 11:31 ` [PATCH 3/3] static_call: Fix static_call_update() sanity check Peter Zijlstra
2021-03-18 11:42 ` Peter Zijlstra
2021-03-18 16:13 ` Josh Poimboeuf
2021-03-18 16:58 ` Peter Zijlstra
2021-03-19 12:57 ` Peter Zijlstra
2021-03-19 18:00 ` Steven Rostedt
2021-03-19 19:34 ` Peter Zijlstra
2021-03-19 20:57 ` Steven Rostedt
2021-03-22 14:50 ` Jessica Yu
2021-03-22 16:54 ` Peter Zijlstra
2021-03-22 17:36 ` Jessica Yu
2021-03-22 13:07 ` Jessica Yu
2021-03-22 14:06 ` Peter Zijlstra
2021-03-19 12:25 ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2021-03-18 12:15 ` [PATCH 0/3] static_call() vs __exit fixes Sumit Garg
2021-03-18 19:38 ` Jarkko Sakkinen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YFjM3HgyZS14x0m/@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=ardb@kernel.org \
--cc=jarkko@kernel.org \
--cc=jbaron@akamai.com \
--cc=jpoimboe@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=oliver.sang@intel.com \
--cc=rostedt@goodmis.org \
--cc=sumit.garg@linaro.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).