linux-kernel - Re: [PATCH 14/19] rcu/context-tracking: Move RCU-dynticks internal functions to context

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sun, 13 Mar 2022 00:10:48 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Frederic Weisbecker <frederic@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>, Phil Auld <pauld@...hat.com>,
        Alex Belits <abelits@...vell.com>,
        Nicolas Saenz Julienne <nsaenz@...nel.org>,
        Xiongfeng Wang <wangxiongfeng2@...wei.com>,
        Neeraj Upadhyay <quic_neeraju@...cinc.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Yu Liao <liaoyu15@...wei.com>,
        Boqun Feng <boqun.feng@...il.com>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        Uladzislau Rezki <uladzislau.rezki@...y.com>,
        Joel Fernandes <joel@...lfernandes.org>
Subject: Re: [PATCH 14/19] rcu/context-tracking: Move RCU-dynticks internal
 functions to context_tracking

On Wed, Mar 02, 2022 at 04:48:05PM +0100, Frederic Weisbecker wrote:
> +noinstr unsigned long rcu_dynticks_inc(int incby)
> +{
> +	return arch_atomic_add_return(incby, this_cpu_ptr(&context_tracking.dynticks));
> +}

noinstr implies noinline, making the above a rather sad little function;
would it perhaps be better to make it __always_inline ?

Also; I could imagine myself doing an arch special for this such that
x86 generates:

	LOCK XADD	[reg], %gs:[var]

But that's for later I suppose, it would be but a little tweak to
perpcu_add_return_op()