Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756164AbbLDL5k (ORCPT ); Fri, 4 Dec 2015 06:57:40 -0500 Received: from terminus.zytor.com ([198.137.202.10]:60243 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756111AbbLDL5i (ORCPT ); Fri, 4 Dec 2015 06:57:38 -0500 Date: Fri, 4 Dec 2015 03:56:45 -0800 From: tip-bot for Frederic Weisbecker Message-ID: Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, riel@redhat.com, h-shimamoto@ct.jp.nec.com, torvalds@linux-foundation.org, fweisbec@gmail.com, tglx@linutronix.de, hpa@zytor.com, efault@gmx.de, lcapitulino@redhat.com, mingo@kernel.org, paulmck@linux.vnet.ibm.com, cmetcalf@ezchip.com, cl@linux.com Reply-To: peterz@infradead.org, linux-kernel@vger.kernel.org, h-shimamoto@ct.jp.nec.com, riel@redhat.com, tglx@linutronix.de, fweisbec@gmail.com, torvalds@linux-foundation.org, hpa@zytor.com, cmetcalf@ezchip.com, paulmck@linux.vnet.ibm.com, efault@gmx.de, mingo@kernel.org, lcapitulino@redhat.com, cl@linux.com In-Reply-To: <1447948054-28668-8-git-send-email-fweisbec@gmail.com> References: <1447948054-28668-8-git-send-email-fweisbec@gmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/cputime: Convert vtime_seqlock to seqcount Git-Commit-ID: b7ce2277f087fd052e7e1bbf432f7fecbee82bb6 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7452 Lines: 220 Commit-ID: b7ce2277f087fd052e7e1bbf432f7fecbee82bb6 Gitweb: http://git.kernel.org/tip/b7ce2277f087fd052e7e1bbf432f7fecbee82bb6 Author: Frederic Weisbecker AuthorDate: Thu, 19 Nov 2015 16:47:34 +0100 Committer: Ingo Molnar CommitDate: Fri, 4 Dec 2015 10:34:46 +0100 sched/cputime: Convert vtime_seqlock to seqcount The cputime can only be updated by the current task itself, even in vtime case. So we can safely use seqcount instead of seqlock as there is no writer concurrency involved. Signed-off-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra (Intel) Cc: Chris Metcalf Cc: Christoph Lameter Cc: Hiroshi Shimamoto Cc: Linus Torvalds Cc: Luiz Capitulino Cc: Mike Galbraith Cc: Paul E . McKenney Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1447948054-28668-8-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar --- include/linux/init_task.h | 2 +- include/linux/sched.h | 2 +- kernel/fork.c | 2 +- kernel/sched/cputime.c | 46 ++++++++++++++++++++++++---------------------- 4 files changed, 27 insertions(+), 25 deletions(-) diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 1c1ff7e..f2cb8d4 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -150,7 +150,7 @@ extern struct task_group root_task_group; #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN # define INIT_VTIME(tsk) \ - .vtime_seqlock = __SEQLOCK_UNLOCKED(tsk.vtime_seqlock), \ + .vtime_seqcount = SEQCNT_ZERO(tsk.vtime_seqcount), \ .vtime_snap = 0, \ .vtime_snap_whence = VTIME_SYS, #else diff --git a/include/linux/sched.h b/include/linux/sched.h index 3533168..3b0de68 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1519,7 +1519,7 @@ struct task_struct { cputime_t gtime; struct prev_cputime prev_cputime; #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN - seqlock_t vtime_seqlock; + seqcount_t vtime_seqcount; unsigned long long vtime_snap; enum { /* Task is sleeping or running in a CPU with VTIME inactive */ diff --git a/kernel/fork.c b/kernel/fork.c index c0a1370..eea32b5 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1348,7 +1348,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, prev_cputime_init(&p->prev_cputime); #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN - seqlock_init(&p->vtime_seqlock); + seqcount_init(&p->vtime_seqcount); p->vtime_snap = 0; p->vtime_snap_whence = VTIME_INACTIVE; #endif diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index 9989c3f..d5ff5c6 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -696,37 +696,37 @@ static void __vtime_account_system(struct task_struct *tsk) void vtime_account_system(struct task_struct *tsk) { - write_seqlock(&tsk->vtime_seqlock); + write_seqcount_begin(&tsk->vtime_seqcount); __vtime_account_system(tsk); - write_sequnlock(&tsk->vtime_seqlock); + write_seqcount_end(&tsk->vtime_seqcount); } void vtime_gen_account_irq_exit(struct task_struct *tsk) { - write_seqlock(&tsk->vtime_seqlock); + write_seqcount_begin(&tsk->vtime_seqcount); __vtime_account_system(tsk); if (context_tracking_in_user()) tsk->vtime_snap_whence = VTIME_USER; - write_sequnlock(&tsk->vtime_seqlock); + write_seqcount_end(&tsk->vtime_seqcount); } void vtime_account_user(struct task_struct *tsk) { cputime_t delta_cpu; - write_seqlock(&tsk->vtime_seqlock); + write_seqcount_begin(&tsk->vtime_seqcount); delta_cpu = get_vtime_delta(tsk); tsk->vtime_snap_whence = VTIME_SYS; account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu)); - write_sequnlock(&tsk->vtime_seqlock); + write_seqcount_end(&tsk->vtime_seqcount); } void vtime_user_enter(struct task_struct *tsk) { - write_seqlock(&tsk->vtime_seqlock); + write_seqcount_begin(&tsk->vtime_seqcount); __vtime_account_system(tsk); tsk->vtime_snap_whence = VTIME_USER; - write_sequnlock(&tsk->vtime_seqlock); + write_seqcount_end(&tsk->vtime_seqcount); } void vtime_guest_enter(struct task_struct *tsk) @@ -738,19 +738,19 @@ void vtime_guest_enter(struct task_struct *tsk) * synchronization against the reader (task_gtime()) * that can thus safely catch up with a tickless delta. */ - write_seqlock(&tsk->vtime_seqlock); + write_seqcount_begin(&tsk->vtime_seqcount); __vtime_account_system(tsk); current->flags |= PF_VCPU; - write_sequnlock(&tsk->vtime_seqlock); + write_seqcount_end(&tsk->vtime_seqcount); } EXPORT_SYMBOL_GPL(vtime_guest_enter); void vtime_guest_exit(struct task_struct *tsk) { - write_seqlock(&tsk->vtime_seqlock); + write_seqcount_begin(&tsk->vtime_seqcount); __vtime_account_system(tsk); current->flags &= ~PF_VCPU; - write_sequnlock(&tsk->vtime_seqlock); + write_seqcount_end(&tsk->vtime_seqcount); } EXPORT_SYMBOL_GPL(vtime_guest_exit); @@ -763,24 +763,26 @@ void vtime_account_idle(struct task_struct *tsk) void arch_vtime_task_switch(struct task_struct *prev) { - write_seqlock(&prev->vtime_seqlock); + write_seqcount_begin(&prev->vtime_seqcount); prev->vtime_snap_whence = VTIME_INACTIVE; - write_sequnlock(&prev->vtime_seqlock); + write_seqcount_end(&prev->vtime_seqcount); - write_seqlock(¤t->vtime_seqlock); + write_seqcount_begin(¤t->vtime_seqcount); current->vtime_snap_whence = VTIME_SYS; current->vtime_snap = sched_clock_cpu(smp_processor_id()); - write_sequnlock(¤t->vtime_seqlock); + write_seqcount_end(¤t->vtime_seqcount); } void vtime_init_idle(struct task_struct *t, int cpu) { unsigned long flags; - write_seqlock_irqsave(&t->vtime_seqlock, flags); + local_irq_save(flags); + write_seqcount_begin(&t->vtime_seqcount); t->vtime_snap_whence = VTIME_SYS; t->vtime_snap = sched_clock_cpu(cpu); - write_sequnlock_irqrestore(&t->vtime_seqlock, flags); + write_seqcount_end(&t->vtime_seqcount); + local_irq_restore(flags); } cputime_t task_gtime(struct task_struct *t) @@ -792,13 +794,13 @@ cputime_t task_gtime(struct task_struct *t) return t->gtime; do { - seq = read_seqbegin(&t->vtime_seqlock); + seq = read_seqcount_begin(&t->vtime_seqcount); gtime = t->gtime; if (t->vtime_snap_whence == VTIME_SYS && t->flags & PF_VCPU) gtime += vtime_delta(t); - } while (read_seqretry(&t->vtime_seqlock, seq)); + } while (read_seqcount_retry(&t->vtime_seqcount, seq)); return gtime; } @@ -821,7 +823,7 @@ fetch_task_cputime(struct task_struct *t, *udelta = 0; *sdelta = 0; - seq = read_seqbegin(&t->vtime_seqlock); + seq = read_seqcount_begin(&t->vtime_seqcount); if (u_dst) *u_dst = *u_src; @@ -845,7 +847,7 @@ fetch_task_cputime(struct task_struct *t, if (t->vtime_snap_whence == VTIME_SYS) *sdelta = delta; } - } while (read_seqretry(&t->vtime_seqlock, seq)); + } while (read_seqcount_retry(&t->vtime_seqcount, seq)); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/