From patchwork Tue Jul 17 21:49:25 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: john stultz X-Patchwork-Id: 10078 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id 142D723E3D for ; Tue, 17 Jul 2012 21:49:48 +0000 (UTC) Received: from mail-yx0-f180.google.com (mail-yx0-f180.google.com [209.85.213.180]) by fiordland.canonical.com (Postfix) with ESMTP id C1D9CA181FE for ; Tue, 17 Jul 2012 21:49:47 +0000 (UTC) Received: by yenq6 with SMTP id q6so1043846yen.11 for ; Tue, 17 Jul 2012 14:49:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-forwarded-to:x-forwarded-for:delivered-to:received-spf:from:to:cc :subject:date:message-id:x-mailer:in-reply-to:references :x-content-scanned:x-cbid:x-gm-message-state; bh=u0oOGmnXYm4kVt5ccSXU5nv1VZKngdqoOu1w+9wuxL8=; b=ic+pb7nrzNk7M6LM/ejl5oSBsA6LdjX+bBEEKlxK/kbcN45wWLzZ9J4wAjpkk+eDC/ tL711YbZRPpYFU9Kw65HmmwSoZJBmZk2rlyWLT8EfX9hxDGASzwduCyvnw2Mx8wEg1Yu MXyVdpkZ/XIIXD5HBfUPFFUNACS+5qt0xVGnyHep543ZuoZISFJ4sdYshkG266yQAOmF pbza9U4wN7RnHyz9pm9uf41RIx+44Qa/odtgx8uNKZqn1qwzeQwt271rcb44ONEa6uB8 CZFxrY19/F7TZA6gfj5EhVPHpmCWTSaOOMVuCHxDQ17RroAkKLee/WxGaqwU+LDdhI0O GvuA== Received: by 10.50.40.193 with SMTP id z1mr257280igk.0.1342561786719; Tue, 17 Jul 2012 14:49:46 -0700 (PDT) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.231.241.2 with SMTP id lc2csp24859ibb; Tue, 17 Jul 2012 14:49:46 -0700 (PDT) Received: by 10.182.192.41 with SMTP id hd9mr5797536obc.17.1342561785659; Tue, 17 Jul 2012 14:49:45 -0700 (PDT) Received: from e39.co.us.ibm.com (e39.co.us.ibm.com. 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Violators will be prosecuted; Tue, 17 Jul 2012 15:49:42 -0600 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id DC141C40004 for ; Tue, 17 Jul 2012 21:49:40 +0000 (WET) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q6HLnfeN156078 for ; Tue, 17 Jul 2012 15:49:41 -0600 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q6HLneqT026634 for ; Tue, 17 Jul 2012 15:49:40 -0600 Received: from kernel.stglabs.ibm.com (kernel.stglabs.ibm.com [9.114.214.19]) by d03av05.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id q6HLnZI3026401; Tue, 17 Jul 2012 15:49:39 -0600 From: John Stultz To: stable@vger.kernel.org Cc: John Stultz , Thomas Gleixner , Prarit Bhargava , Linux Kernel Subject: [PATCH 05/11] 2.6.34.x: hrtimer: Provide clock_was_set_delayed() Date: Tue, 17 Jul 2012 17:49:25 -0400 Message-Id: <1342561771-55678-6-git-send-email-johnstul@us.ibm.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1342561771-55678-1-git-send-email-johnstul@us.ibm.com> References: <1342561771-55678-1-git-send-email-johnstul@us.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12071721-4242-0000-0000-0000025CA490 X-Gm-Message-State: ALoCoQkwPxqvFAHhV2tFJCxBG6pDAxIhOvutLEgQZmZmbOMsHnPfYlb6sOOQB6S1l8fVSB38qTMD This is a backport of f55a6faa384304c89cfef162768e88374d3312cb clock_was_set() cannot be called from hard interrupt context because it calls on_each_cpu(). For fixing the widely reported leap seconds issue it is necessary to call it from hard interrupt context, i.e. the timer tick code, which does the timekeeping updates. Provide a new function which denotes it in the hrtimer cpu base structure of the cpu on which it is called and raise the hrtimer softirq. We then execute the clock_was_set() notificiation from softirq context in run_hrtimer_softirq(). The hrtimer softirq is rarely used, so polling the flag there is not a performance issue. [ tglx: Made it depend on CONFIG_HIGH_RES_TIMERS. We really should get rid of all this ifdeffery ASAP ] Signed-off-by: John Stultz Reported-by: Jan Engelhardt Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Prarit Bhargava Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1341960205-56738-2-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner Cc: Prarit Bhargava Cc: Thomas Gleixner Cc: Linux Kernel Signed-off-by: John Stultz --- include/linux/hrtimer.h | 7 +++++++ kernel/hrtimer.c | 20 ++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 5d86fb2..0325598 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -159,6 +159,7 @@ struct hrtimer_clock_base { * and timers * @clock_base: array of clock bases for this cpu * @curr_timer: the timer which is executing a callback right now + * @clock_was_set: Indicates that clock was set from irq context. * @expires_next: absolute time of the next event which was scheduled * via clock_set_next_event() * @hres_active: State of high resolution mode @@ -171,6 +172,7 @@ struct hrtimer_clock_base { struct hrtimer_cpu_base { raw_spinlock_t lock; struct hrtimer_clock_base clock_base[HRTIMER_MAX_CLOCK_BASES]; + unsigned int clock_was_set; #ifdef CONFIG_HIGH_RES_TIMERS ktime_t expires_next; int hres_active; @@ -280,6 +282,8 @@ extern void hrtimer_peek_ahead_timers(void); # define MONOTONIC_RES_NSEC HIGH_RES_NSEC # define KTIME_MONOTONIC_RES KTIME_HIGH_RES +extern void clock_was_set_delayed(void); + #else # define MONOTONIC_RES_NSEC LOW_RES_NSEC @@ -308,6 +312,9 @@ static inline int hrtimer_is_hres_active(struct hrtimer *timer) { return 0; } + +static inline void clock_was_set_delayed(void) { } + #endif extern ktime_t ktime_get(void); diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c index 3c727aa..dc41268 100644 --- a/kernel/hrtimer.c +++ b/kernel/hrtimer.c @@ -738,6 +738,19 @@ static int hrtimer_switch_to_hres(void) return 1; } +/* + * Called from timekeeping code to reprogramm the hrtimer interrupt + * device. If called from the timer interrupt context we defer it to + * softirq context. + */ +void clock_was_set_delayed(void) +{ + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + + cpu_base->clock_was_set = 1; + __raise_softirq_irqoff(HRTIMER_SOFTIRQ); +} + #else static inline int hrtimer_hres_active(void) { return 0; } @@ -1409,6 +1422,13 @@ void hrtimer_peek_ahead_timers(void) static void run_hrtimer_softirq(struct softirq_action *h) { + struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases); + + if (cpu_base->clock_was_set) { + cpu_base->clock_was_set = 0; + clock_was_set(); + } + hrtimer_peek_ahead_timers(); }