From da8b44d5a9f8bf26da637b7336508ca534d6b319 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 17 Mar 2016 14:20:51 -0700 Subject: timer: convert timer_slack_ns from unsigned long to u64 This patchset introduces a /proc//timerslack_ns interface which would allow controlling processes to be able to set the timerslack value on other processes in order to save power by avoiding wakeups (Something Android currently does via out-of-tree patches). The first patch tries to fix the internal timer_slack_ns usage which was defined as a long, which limits the slack range to ~4 seconds on 32bit systems. It converts it to a u64, which provides the same basically unlimited slack (500 years) on both 32bit and 64bit machines. The second patch introduces the /proc//timerslack_ns interface which allows the full 64bit slack range for a task to be read or set on both 32bit and 64bit machines. With these two patches, on a 32bit machine, after setting the slack on bash to 10 seconds: $ time sleep 1 real 0m10.747s user 0m0.001s sys 0m0.005s The first patch is a little ugly, since I had to chase the slack delta arguments through a number of functions converting them to u64s. Let me know if it makes sense to break that up more or not. Other than that things are fairly straightforward. This patch (of 2): The timer_slack_ns value in the task struct is currently a unsigned long. This means that on 32bit applications, the maximum slack is just over 4 seconds. However, on 64bit machines, its much much larger (~500 years). This disparity could make application development a little (as well as the default_slack) to a u64. This means both 32bit and 64bit systems have the same effective internal slack range. Now the existing ABI via PR_GET_TIMERSLACK and PR_SET_TIMERSLACK specify the interface as a unsigned long, so we preserve that limitation on 32bit systems, where SET_TIMERSLACK can only set the slack to a unsigned long value, and GET_TIMERSLACK will return ULONG_MAX if the slack is actually larger then what can be stored by an unsigned long. This patch also modifies hrtimer functions which specified the slack delta as a unsigned long. Signed-off-by: John Stultz Cc: Arjan van de Ven Cc: Thomas Gleixner Cc: Oren Laadan Cc: Ruchi Kandoi Cc: Rom Lemarchand Cc: Kees Cook Cc: Android Kernel Team Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/time/hrtimer.c | 8 ++++---- kernel/time/timer.c | 4 ++-- 2 files changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index fa909f9fd559..58a321c34cfb 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -979,7 +979,7 @@ static inline ktime_t hrtimer_update_lowres(struct hrtimer *timer, ktime_t tim, * relative (HRTIMER_MODE_REL) */ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim, - unsigned long delta_ns, const enum hrtimer_mode mode) + u64 delta_ns, const enum hrtimer_mode mode) { struct hrtimer_clock_base *base, *new_base; unsigned long flags; @@ -1548,7 +1548,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp, struct restart_block *restart; struct hrtimer_sleeper t; int ret = 0; - unsigned long slack; + u64 slack; slack = current->timer_slack_ns; if (dl_task(current) || rt_task(current)) @@ -1724,7 +1724,7 @@ void __init hrtimers_init(void) * @clock: timer clock, CLOCK_MONOTONIC or CLOCK_REALTIME */ int __sched -schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, +schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta, const enum hrtimer_mode mode, int clock) { struct hrtimer_sleeper t; @@ -1792,7 +1792,7 @@ schedule_hrtimeout_range_clock(ktime_t *expires, unsigned long delta, * * Returns 0 when the timer has expired otherwise -EINTR */ -int __sched schedule_hrtimeout_range(ktime_t *expires, unsigned long delta, +int __sched schedule_hrtimeout_range(ktime_t *expires, u64 delta, const enum hrtimer_mode mode) { return schedule_hrtimeout_range_clock(expires, delta, mode, diff --git a/kernel/time/timer.c b/kernel/time/timer.c index bbc5d1114583..d1798fa0c743 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1698,10 +1698,10 @@ EXPORT_SYMBOL(msleep_interruptible); static void __sched do_usleep_range(unsigned long min, unsigned long max) { ktime_t kmin; - unsigned long delta; + u64 delta; kmin = ktime_set(0, min * NSEC_PER_USEC); - delta = (max - min) * NSEC_PER_USEC; + delta = (u64)(max - min) * NSEC_PER_USEC; schedule_hrtimeout_range(&kmin, delta, HRTIMER_MODE_REL); } -- cgit v1.2.3 From 4cc7ecb7f2a60e8deb783b8fbf7c1ae467acb920 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 17 Mar 2016 14:23:00 -0700 Subject: param: convert some "on"/"off" users to strtobool This changes several users of manual "on"/"off" parsing to use strtobool. Some side-effects: - these uses will now parse y/n/1/0 meaningfully too - the early_param uses will now bubble up parse errors Signed-off-by: Kees Cook Acked-by: Heiko Carstens Acked-by: Michael Ellerman Cc: Amitkumar Karwar Cc: Andy Shevchenko Cc: Daniel Borkmann Cc: Joe Perches Cc: Kalle Valo Cc: Martin Schwidefsky Cc: Nishant Sarmukadam Cc: Rasmus Villemoes Cc: Steve French Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/powerpc/kernel/rtasd.c | 9 ++------- arch/powerpc/platforms/pseries/hotplug-cpu.c | 10 ++-------- arch/s390/kernel/time.c | 8 ++------ arch/s390/kernel/topology.c | 7 ++----- arch/x86/kernel/aperture_64.c | 12 ++---------- include/linux/tick.h | 2 +- kernel/time/hrtimer.c | 10 ++-------- kernel/time/tick-sched.c | 10 ++-------- 8 files changed, 15 insertions(+), 53 deletions(-) (limited to 'kernel/time') diff --git a/arch/powerpc/kernel/rtasd.c b/arch/powerpc/kernel/rtasd.c index 5a2c049c1c61..aa610ce8742f 100644 --- a/arch/powerpc/kernel/rtasd.c +++ b/arch/powerpc/kernel/rtasd.c @@ -49,7 +49,7 @@ static unsigned int rtas_error_log_buffer_max; static unsigned int event_scan; static unsigned int rtas_event_scan_rate; -static int full_rtas_msgs = 0; +static bool full_rtas_msgs; /* Stop logging to nvram after first fatal error */ static int logging_enabled; /* Until we initialize everything, @@ -592,11 +592,6 @@ __setup("surveillance=", surveillance_setup); static int __init rtasmsgs_setup(char *str) { - if (strcmp(str, "on") == 0) - full_rtas_msgs = 1; - else if (strcmp(str, "off") == 0) - full_rtas_msgs = 0; - - return 1; + return (kstrtobool(str, &full_rtas_msgs) == 0); } __setup("rtasmsgs=", rtasmsgs_setup); diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index 32274f72fe3f..282837a1d74b 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -47,20 +47,14 @@ static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE; static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE; -static int cede_offline_enabled __read_mostly = 1; +static bool cede_offline_enabled __read_mostly = true; /* * Enable/disable cede_offline when available. */ static int __init setup_cede_offline(char *str) { - if (!strcmp(str, "off")) - cede_offline_enabled = 0; - else if (!strcmp(str, "on")) - cede_offline_enabled = 1; - else - return 0; - return 1; + return (kstrtobool(str, &cede_offline_enabled) == 0); } __setup("cede_offline=", setup_cede_offline); diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index c4e5f183f225..9409d32f285e 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -1432,7 +1432,7 @@ device_initcall(etr_init_sysfs); /* * Server Time Protocol (STP) code. */ -static int stp_online; +static bool stp_online; static struct stp_sstpi stp_info; static void *stp_page; @@ -1443,11 +1443,7 @@ static struct timer_list stp_timer; static int __init early_parse_stp(char *p) { - if (strncmp(p, "off", 3) == 0) - stp_online = 0; - else if (strncmp(p, "on", 2) == 0) - stp_online = 1; - return 0; + return kstrtobool(p, &stp_online); } early_param("stp", early_parse_stp); diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c index 40b8102fdadb..64298a867589 100644 --- a/arch/s390/kernel/topology.c +++ b/arch/s390/kernel/topology.c @@ -37,7 +37,7 @@ static void set_topology_timer(void); static void topology_work_fn(struct work_struct *work); static struct sysinfo_15_1_x *tl_info; -static int topology_enabled = 1; +static bool topology_enabled = true; static DECLARE_WORK(topology_work, topology_work_fn); /* @@ -444,10 +444,7 @@ static const struct cpumask *cpu_book_mask(int cpu) static int __init early_parse_topology(char *p) { - if (strncmp(p, "off", 3)) - return 0; - topology_enabled = 0; - return 0; + return kstrtobool(p, &topology_enabled); } early_param("topology", early_parse_topology); diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c index 6e85f713641d..0a2bb1f62e72 100644 --- a/arch/x86/kernel/aperture_64.c +++ b/arch/x86/kernel/aperture_64.c @@ -227,19 +227,11 @@ static u32 __init search_agp_bridge(u32 *order, int *valid_agp) return 0; } -static int gart_fix_e820 __initdata = 1; +static bool gart_fix_e820 __initdata = true; static int __init parse_gart_mem(char *p) { - if (!p) - return -EINVAL; - - if (!strncmp(p, "off", 3)) - gart_fix_e820 = 0; - else if (!strncmp(p, "on", 2)) - gart_fix_e820 = 1; - - return 0; + return kstrtobool(p, &gart_fix_e820); } early_param("gart_fix_e820", parse_gart_mem); diff --git a/include/linux/tick.h b/include/linux/tick.h index 21f73649a4dc..62be0786d6d0 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -111,7 +111,7 @@ enum tick_dep_bits { #define TICK_DEP_MASK_CLOCK_UNSTABLE (1 << TICK_DEP_BIT_CLOCK_UNSTABLE) #ifdef CONFIG_NO_HZ_COMMON -extern int tick_nohz_enabled; +extern bool tick_nohz_enabled; extern int tick_nohz_tick_stopped(void); extern void tick_nohz_idle_enter(void); extern void tick_nohz_idle_exit(void); diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 58a321c34cfb..fa0b983290cf 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -515,7 +515,7 @@ static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base) /* * High resolution timer enabled ? */ -static int hrtimer_hres_enabled __read_mostly = 1; +static bool hrtimer_hres_enabled __read_mostly = true; unsigned int hrtimer_resolution __read_mostly = LOW_RES_NSEC; EXPORT_SYMBOL_GPL(hrtimer_resolution); @@ -524,13 +524,7 @@ EXPORT_SYMBOL_GPL(hrtimer_resolution); */ static int __init setup_hrtimer_hres(char *str) { - if (!strcmp(str, "off")) - hrtimer_hres_enabled = 0; - else if (!strcmp(str, "on")) - hrtimer_hres_enabled = 1; - else - return 0; - return 1; + return (kstrtobool(str, &hrtimer_hres_enabled) == 0); } __setup("highres=", setup_hrtimer_hres); diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 969e6704c3c9..195fe7d2caad 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -486,20 +486,14 @@ void __init tick_nohz_init(void) /* * NO HZ enabled ? */ -int tick_nohz_enabled __read_mostly = 1; +bool tick_nohz_enabled __read_mostly = true; unsigned long tick_nohz_active __read_mostly; /* * Enable / Disable tickless mode */ static int __init setup_tick_nohz(char *str) { - if (!strcmp(str, "off")) - tick_nohz_enabled = 0; - else if (!strcmp(str, "on")) - tick_nohz_enabled = 1; - else - return 0; - return 1; + return (kstrtobool(str, &tick_nohz_enabled) == 0); } __setup("nohz=", setup_tick_nohz); -- cgit v1.2.3