cpuidle/governors/haltpoll.c

1 // SPDX-License-Identifier: GPL-2.0
3  * haltpoll.c - haltpoll idle governor
8  * the COPYING file in the top-level directory.
31 /* multiplication factor to grow per-cpu poll_limit_ns */
35 /* value in us to start growing per-cpu halt_poll_ns */
39 /* allow shrinking guest halt poll */
44  * haltpoll_select - selects the next idle state to enter
53 	s64 latency_req = cpuidle_governor_latency_req(dev->cpu);  in haltpoll_select()
55 	if (!drv->state_count || latency_req == 0) {  in haltpoll_select()
60 	if (dev->poll_limit_ns == 0)  in haltpoll_select()
64 	if (dev->last_state_idx == 0) {  in haltpoll_select()
65 		/* Halt if no event occurred on poll window */  in haltpoll_select()
66 		if (dev->poll_time_limit == true)  in haltpoll_select()
75 	/* Last state was halt: poll */  in haltpoll_select()
86 	if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {  in adjust_poll_limit()
87 		val = dev->poll_limit_ns * guest_halt_poll_grow;  in adjust_poll_limit()
94 		trace_guest_halt_poll_ns_grow(val, dev->poll_limit_ns);  in adjust_poll_limit()
95 		dev->poll_limit_ns = val;  in adjust_poll_limit()
100 		val = dev->poll_limit_ns;  in adjust_poll_limit()
110 		trace_guest_halt_poll_ns_shrink(val, dev->poll_limit_ns);  in adjust_poll_limit()
111 		dev->poll_limit_ns = val;  in adjust_poll_limit()
116  * haltpoll_reflect - update variables and update poll time
122 	dev->last_state_idx = index;  in haltpoll_reflect()
125 		adjust_poll_limit(dev, dev->last_residency_ns);  in haltpoll_reflect()
129  * haltpoll_enable_device - scans a CPU's states and does setup
136 	dev->poll_limit_ns = 0;  in haltpoll_enable_device()