From nobody Mon Feb 9 15:06:43 2026 Received: from mail-pj1-f73.google.com (mail-pj1-f73.google.com [209.85.216.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E6F5D25602 for ; Wed, 7 Feb 2024 10:06:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707300395; cv=none; b=YK5U2I5NciLs8OX/DW0H88QL/bDnpL4cKRBW4qNGUVOiMnidisXBOWmUlfp8M1MvzWg8Y8uyaW/cyMgB2g15FZ2bdQAwIpVzJeqq/AD3yQEK4DISx+/buBU8uUPkLW9o4UBS60K1kOEw2jYBxS3ipErkN+68Y1L/8g806c/T1ck= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707300395; c=relaxed/simple; bh=e+QYfe3EBAnFeI6C06KSlz6hgCpRzI0/cX5GEtPsNfg=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Fgf40/LemyrFGbzrv7xXxRSUoFDw//E7UIUu9HdiAnZnEUyoKwLJBrtb0FQnjPN9w2rE5nUQ5FzRY9M6VO3RjE/HlpyPEsEuFnUtbpR/QNi4GUHPf0DuV2vaZAwvN67PR7OnhzSSXzZN1nVWJmV/MtKdWOVGJvZIa0TWF0i0unQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--pranavpp.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=IeMtiH1Z; arc=none smtp.client-ip=209.85.216.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--pranavpp.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="IeMtiH1Z" Received: by mail-pj1-f73.google.com with SMTP id 98e67ed59e1d1-296e09c305eso488152a91.1 for ; Wed, 07 Feb 2024 02:06:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707300393; x=1707905193; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=JHyxNaPCKju0suiGcb7YkRX+LpmSfcg8/gQ3kq3ldf8=; b=IeMtiH1ZN91C6+yvDyPuFLmRl+pabFaac/Lhm0oSRLDv3V3AbDbTIYzIDZAcgRIXo/ rJVDYtBKLShXpVPFWMI51ur24FWRSvXZ2DMDJhgr3KxvJVJAloASj6NW8wl9hrYS+rUK ZzUglr3SExuyb+/5Fc9hAvfY+08Gxf4i3JpwAuGLUoBRz5F0caabMxP6AVkxM88MNSz/ SmbZAvjklHC/juUS/iCXrlxmc2X48GXupNMYVB5mxPPZUbIZR4LQDw/9k5q4hoGZe9SC WpBYWMBMRq/EZTBwCQgw1MlEGfIBSF2WnZjTZHj0xc2uI0OOEI12CpO0T5NFVLzhOkYQ qLHA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707300393; x=1707905193; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=JHyxNaPCKju0suiGcb7YkRX+LpmSfcg8/gQ3kq3ldf8=; b=jeilbY+gisMopPPsShT59sNWbHjBs+4mvi3WPExDrNhnP//nBzgOhAcbEUD6zgY8g/ ui0fQue0qwu4SfPO25H3g93/+7yssWuwdkssBl/4HHkLVX0a5/KEmevJArNiC37UnIH5 SIFdShHn9AbuGhtaYxPr0ZEIKhcYSllQlq9u3nyyYqx5FmW/FTDpw1/t99Y4rpj5sZg+ owHkM+zAO6ii9yR1Pz2EATkmUfcBltTvpM+vPlk5v0CCBpbITSL2XZLvzGtg0MOmyOSm jxCN7YYP8YUwKBdymk4DRB+BZIXMfzMcY1VXZbB+UMQjejghWNDhgsPgaYrGoS0vKvCI 0QfA== X-Gm-Message-State: AOJu0YypjgjNLZkzXK2K6UUoM5Rl8kOlv3MdpbGKAp3JQXZy2pQ00zY/ k/2ZWHGizKSLEe1ocd5x6uNEaRzMsEv4rMjLRlt6Kto1pfV+pmaVBP2ClwkVIpa4zyAomp+zhqU JK+gL99yxvw== X-Google-Smtp-Source: AGHT+IFTya2ZyeZ/C36rVXr9zqm2bHORKHvP6G9MfSZoDZoGhxV1NyJpb+dnBDqe/z8HmrRbZ8laRTzSvJ3YXw== X-Received: from pranav-first.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:390b]) (user=pranavpp job=sendgmr) by 2002:a17:90a:cc3:b0:296:dd68:e4d4 with SMTP id 3-20020a17090a0cc300b00296dd68e4d4mr36447pjt.3.1707300393162; Wed, 07 Feb 2024 02:06:33 -0800 (PST) Date: Wed, 7 Feb 2024 10:06:18 +0000 In-Reply-To: <20240207100619.3947442-1-pranavpp@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240207100619.3947442-1-pranavpp@google.com> X-Mailer: git-send-email 2.43.0.594.gd9cf4e227d-goog Message-ID: <20240207100619.3947442-2-pranavpp@google.com> Subject: [PATCH 1/2] alarmtimer: Create alarmtimer sysfs to make duration of kernel suspend check configurable From: Pranav Prasad To: tglx@linutronix.de, jstultz@google.com, sboyd@kernel.org Cc: linux-kernel@vger.kernel.org, Pranav Prasad , Kelly Rossmoyer Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Currently, the alarmtimer_suspend does not allow the kernel to suspend if the next alarm is within 2 seconds. Create alarmtimer sysfs to make the value of 2 seconds configurable. This allows flexibility to provide a different value based on the type of device running the Linux kernel. As a data point, about 40% of kernel suspend failures in a subset of Android devices were due to this check. A differently configured value can avoid these suspend failures which performs a lot of additional work affecting the power consumption of these Android devices. Signed-off-by: Pranav Prasad Signed-off-by: Kelly Rossmoyer --- kernel/time/alarmtimer.c | 61 ++++++++++++++++++++++++++++++++++++++-- 1 file changed, 58 insertions(+), 3 deletions(-) diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 4657cb8e8b1f..e5d2e560b4c1 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -33,6 +33,8 @@ #define CREATE_TRACE_POINTS #include =20 +static const char alarmtimer_group_name[] =3D "alarmtimer"; + /** * struct alarm_base - Alarm timer bases * @lock: Lock for syncrhonized access to the base @@ -63,6 +65,56 @@ static struct rtc_timer rtctimer; static struct rtc_device *rtcdev; static DEFINE_SPINLOCK(rtcdev_lock); =20 +/* Duration to check for soonest alarm during kernel suspend */ +static u64 suspend_check_duration_ns =3D 2 * NSEC_PER_SEC; + +static ssize_t suspend_check_duration_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%llu\n", suspend_check_duration_ns); +} + +static ssize_t suspend_check_duration_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t n) +{ + u64 val; + + if (kstrtou64(buf, 10, &val)) + return -EINVAL; + + suspend_check_duration_ns =3D val; + + return n; +} + +static struct kobj_attribute suspend_check_duration =3D + __ATTR_RW(suspend_check_duration); + +static struct attribute *alarmtimer_attrs[] =3D { + &suspend_check_duration.attr, + NULL, +}; + +static const struct attribute_group alarmtimer_attr_group =3D { + .name =3D alarmtimer_group_name, + .attrs =3D alarmtimer_attrs, +}; + +/** + * alarmtimer_sysfs_add - Adds sysfs attributes for alarmtimer + * + * Returns 0 if successful, non-zero value for error. + */ +static int alarmtimer_sysfs_add(void) +{ + int ret =3D sysfs_create_group(kernel_kobj, &alarmtimer_attr_group); + + if (ret) + pr_warn("[%s] failed to create a sysfs group\n", __func__); + + return ret; +} + /** * alarmtimer_get_rtcdev - Return selected rtcdevice * @@ -98,8 +150,11 @@ static int alarmtimer_rtc_add_device(struct device *dev) =20 pdev =3D platform_device_register_data(dev, "alarmtimer", PLATFORM_DEVID_AUTO, NULL, 0); - if (!IS_ERR(pdev)) + if (!IS_ERR(pdev)) { device_init_wakeup(&pdev->dev, true); + if (alarmtimer_sysfs_add()) + pr_warn("[%s] Failed to add alarmtimer sysfs attributes\n", __func__); + } =20 spin_lock_irqsave(&rtcdev_lock, flags); if (!IS_ERR(pdev) && !rtcdev) { @@ -279,8 +334,8 @@ static int alarmtimer_suspend(struct device *dev) if (min =3D=3D 0) return 0; =20 - if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) { - pm_wakeup_event(dev, 2 * MSEC_PER_SEC); + if (ktime_to_ns(min) < suspend_check_duration_ns) { + pm_wakeup_event(dev, suspend_check_duration_ns/NSEC_PER_MSEC); return -EBUSY; } =20 --=20 2.43.0.594.gd9cf4e227d-goog