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
| ||
|
Date: Fri, 3 Apr 2015 19:19:48 +0200 From: Frederic Weisbecker <fweisbec@...il.com> To: Oleg Nesterov <oleg@...hat.com> Cc: LKML <linux-kernel@...r.kernel.org>, Peter Zijlstra <peterz@...radead.org>, Dave Jones <davej@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, "Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>, Ingo Molnar <mingo@...nel.org>, Rik van Riel <riel@...hat.com> Subject: Re: [PATCH 2/3] context_tracking: Inherit TIF_NOHZ through forks instead of context switches On Thu, Apr 02, 2015 at 08:08:03PM +0200, Oleg Nesterov wrote: > On 04/02, Frederic Weisbecker wrote: > > > > +void context_tracking_cpu_set(int cpu) > > { > > - clear_tsk_thread_flag(prev, TIF_NOHZ); > > - set_tsk_thread_flag(next, TIF_NOHZ); > > + static bool initialized = false; > > + struct task_struct *p, *t; > > + unsigned long flags; > > + > > + if (!per_cpu(context_tracking.active, cpu)) { > > + per_cpu(context_tracking.active, cpu) = true; > > + static_key_slow_inc(&context_tracking_enabled); > > + } > > + > > + if (initialized) > > + return; > > + > > + set_tsk_thread_flag(&init_task, TIF_NOHZ); > > + > > + /* > > + * There shouldn't be any thread at this early boot stage > > + * but the scheduler is ready to host any. So lets walk > > + * the tasklist just in case. tasklist_lock isn't necessary > > + * either that early but take it for correctness checkers. > > + */ > > + read_lock_irqsave(&tasklist_lock, flags); > > + for_each_process_thread(p, t) > > + set_tsk_thread_flag(t, TIF_NOHZ); > > + read_unlock_irqrestore(&tasklist_lock, flags); > > + > > + initialized = true; > > } > > Agreed, but _irqsave is not needed. read_lock(tasklist) should work > just fine. Indeed, that was just in case we get more callers but then if it happens, it's their responsibility to fix the callee. So I'll just change that. > > Any reason 3/3 comes as a separate change? I won't argue, just curious. Nope, I should fold them indeed. Thanks. > > Oleg. > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists