From nobody Sun Feb 8 11:44:56 2026 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (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 C31CA383B0 for ; Thu, 8 Feb 2024 19:56:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707422201; cv=none; b=EwRXhgUPUEnWN0ljpVFde87GWsodVTbTl592iURP/TV1dvsBsOFIL+VKXM5bjT13KQ2ko60a+an3aWrizQe4GhQVMV0B/5W878GDuzrpL743mnydLA7rH0C+LjrNvXy9VpV/7I0j/ghG5e8nkymUC9l7SmdDXVsz7Y5YpfsWFLg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707422201; c=relaxed/simple; bh=YuOGVyhQ0G/NAULkmFSuiReHREPJ7BzhTsSx1dgiFmI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=J9Fw+dcbGruiBsSjrXFVXHdAa693hIzh+p8h9XamE3vGzKbfHhwRK8f6v5DGwZTS4BY2wPH/2u8AUSWcgZkzsH1QIcAIyNMBcdvIgf+FL7FY48h3v4WZJVrQaM1ZiZpqycNEvA0Fz3LmgsNTaSGQOL/W0jOTImM8KUxn4A4mhmE= 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=lybLQk+Y; arc=none smtp.client-ip=209.85.128.202 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="lybLQk+Y" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-6047a047f58so4738187b3.3 for ; Thu, 08 Feb 2024 11:56:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1707422198; x=1708026998; 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=zaRZ3wf2NZjQHPcjuUdcp3FA76JczLwqBxReMfEbU8g=; b=lybLQk+YXOmdWEd308D+V3i9jp2QP3QsNjkjSX9FJrbU69f63Zk2Kiu7/FdJYTX+2B DgvCR0CfiiMaYM0fu5e3/pMP+NUSMnGKQGCKcCKMcyqyQjNynXuZ2gm4Hd+ZOn3IAiEW KZkjAV4/SwFsW2IUZgbnX2uzDmHWDMvSJOa8430EGPUgAkc7/liTzgV66bAOsKfV9k6l Fw57rhYXtDXvswcK/f3ENzK4Uk5UrG78/iJn7tGVFUf4l+siZ449WuEXwxZBaSWzquMc L6PRj9xj+EMMjEN/l9kEYYX9o7MmsHCWK3gNtjIumCy7vGPtAosVboQccwklYJ3iMro0 rAiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707422198; x=1708026998; 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=zaRZ3wf2NZjQHPcjuUdcp3FA76JczLwqBxReMfEbU8g=; b=pwF+m0SATDSl3CDzIvNMC8ZQs+ar2xxcoNHMXHxwOiOGaSgF2lLaTtENrVAWdhAlUW J+OMg42vTxnOnsqj4rfxQelaU/dwL7Mdkp7egNMolZOsNJIWR/Nt2yb3ic1p0GRNdty7 Zb7CxEDSc6VOlLovjrvqZIIRtjjpWaYn2Jhz5LKFCuF0iHeBij4gGh/3B0fdPfeGr5Pl +G9n3D1LbapmFGoxbofU8WuBaeFTNcMs7L7eqjZrVgu5QXAJSBAN3kN44gYmuIgJI911 vo9wMROl3mFSrTY1FeXeJ3VUOdwDDzOsUYbCraW2xHg+PULjOePIstrraus1e0ijJin/ 1KHA== X-Gm-Message-State: AOJu0YxN8jTPXhok6hz203IYWYFddVYvItDRy7LHrf2GTO39uusgyh8S Yt7XAfYdK2eLkiJbVXhqJumfQ+FbgRBtrLFueVXGxI7IlJpauuQueK+k429xbbXeVDnIxC0be40 5kAU3au0YEQ== X-Google-Smtp-Source: AGHT+IHcIXKw7zl+teeHhdy4TToU5LqR0glGb5C5kPg/CcccRCV04XsiPSsIlrEAYZZ5RsUQwIVMT/capuezcQ== X-Received: from pranav-first.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:390b]) (user=pranavpp job=sendgmr) by 2002:a0d:d583:0:b0:604:5ca:5ab2 with SMTP id x125-20020a0dd583000000b0060405ca5ab2mr75992ywd.9.1707422198703; Thu, 08 Feb 2024 11:56:38 -0800 (PST) Date: Thu, 8 Feb 2024 19:56:21 +0000 In-Reply-To: <20240208195622.758765-1-pranavpp@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240208195622.758765-1-pranavpp@google.com> X-Mailer: git-send-email 2.43.0.687.g38aa6559b0-goog Message-ID: <20240208195622.758765-2-pranavpp@google.com> Subject: [PATCH v2 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, krossmo@google.com, Pranav Prasad 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 --- 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..e4b88c8dc0e1 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 unsigned long suspend_check_duration_ms =3D 2 * MSEC_PER_SEC; + +static ssize_t suspend_check_duration_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%lu\n", suspend_check_duration_ms); +} + +static ssize_t suspend_check_duration_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t n) +{ + unsigned long val; + + if (kstrtoul(buf, 10, &val)) + return -EINVAL; + + suspend_check_duration_ms =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_ms * NSEC_PER_MSEC) { + pm_wakeup_event(dev, suspend_check_duration_ms); return -EBUSY; } =20 --=20 2.43.0.687.g38aa6559b0-goog