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Message-ID: <201906221104.YRaP3P6c%lkp@intel.com>
Date: Sat, 22 Jun 2019 11:52:09 +0800
From: kbuild test robot <lkp@...el.com>
To: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: kbuild-all@...org, rafael@...nel.org, linux-kernel@...r.kernel.org,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Thomas Gleixner <tglx@...utronix.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"open list:CPU IDLE TIME MANAGEMENT FRAMEWORK"
<linux-pm@...r.kernel.org>
Subject: Re: [PATCH] cpuidle/drivers/mobile: Add new governor for
mobile/embedded systems
Hi Daniel,
I love your patch! Perhaps something to improve:
[auto build test WARNING on pm/linux-next]
[also build test WARNING on v5.2-rc5 next-20190621]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Daniel-Lezcano/cpuidle-drivers-mobile-Add-new-governor-for-mobile-embedded-systems/20190622-064303
base: https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git linux-next
reproduce:
# apt-get install sparse
# sparse version: v0.6.1-rc1-7-g2b96cd8-dirty
make ARCH=x86_64 allmodconfig
make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@...el.com>
sparse warnings: (new ones prefixed by >>)
vim +502 kernel/irq/timings.c
bbba0e7c Daniel Lezcano 2019-03-28 437
e1c92149 Daniel Lezcano 2017-06-23 438 /**
e1c92149 Daniel Lezcano 2017-06-23 439 * irq_timings_next_event - Return when the next event is supposed to arrive
e1c92149 Daniel Lezcano 2017-06-23 440 *
e1c92149 Daniel Lezcano 2017-06-23 441 * During the last busy cycle, the number of interrupts is incremented
e1c92149 Daniel Lezcano 2017-06-23 442 * and stored in the irq_timings structure. This information is
e1c92149 Daniel Lezcano 2017-06-23 443 * necessary to:
e1c92149 Daniel Lezcano 2017-06-23 444 *
e1c92149 Daniel Lezcano 2017-06-23 445 * - know if the index in the table wrapped up:
e1c92149 Daniel Lezcano 2017-06-23 446 *
e1c92149 Daniel Lezcano 2017-06-23 447 * If more than the array size interrupts happened during the
e1c92149 Daniel Lezcano 2017-06-23 448 * last busy/idle cycle, the index wrapped up and we have to
e1c92149 Daniel Lezcano 2017-06-23 449 * begin with the next element in the array which is the last one
e1c92149 Daniel Lezcano 2017-06-23 450 * in the sequence, otherwise it is a the index 0.
e1c92149 Daniel Lezcano 2017-06-23 451 *
e1c92149 Daniel Lezcano 2017-06-23 452 * - have an indication of the interrupts activity on this CPU
e1c92149 Daniel Lezcano 2017-06-23 453 * (eg. irq/sec)
e1c92149 Daniel Lezcano 2017-06-23 454 *
e1c92149 Daniel Lezcano 2017-06-23 455 * The values are 'consumed' after inserting in the statistical model,
e1c92149 Daniel Lezcano 2017-06-23 456 * thus the count is reinitialized.
e1c92149 Daniel Lezcano 2017-06-23 457 *
e1c92149 Daniel Lezcano 2017-06-23 458 * The array of values **must** be browsed in the time direction, the
e1c92149 Daniel Lezcano 2017-06-23 459 * timestamp must increase between an element and the next one.
e1c92149 Daniel Lezcano 2017-06-23 460 *
e1c92149 Daniel Lezcano 2017-06-23 461 * Returns a nanosec time based estimation of the earliest interrupt,
e1c92149 Daniel Lezcano 2017-06-23 462 * U64_MAX otherwise.
e1c92149 Daniel Lezcano 2017-06-23 463 */
e1c92149 Daniel Lezcano 2017-06-23 464 u64 irq_timings_next_event(u64 now)
e1c92149 Daniel Lezcano 2017-06-23 465 {
bbba0e7c Daniel Lezcano 2019-03-28 466 struct irq_timings *irqts = this_cpu_ptr(&irq_timings);
bbba0e7c Daniel Lezcano 2019-03-28 467 struct irqt_stat *irqs;
bbba0e7c Daniel Lezcano 2019-03-28 468 struct irqt_stat __percpu *s;
bbba0e7c Daniel Lezcano 2019-03-28 469 u64 ts, next_evt = U64_MAX;
bbba0e7c Daniel Lezcano 2019-03-28 470 int i, irq = 0;
bbba0e7c Daniel Lezcano 2019-03-28 471
e1c92149 Daniel Lezcano 2017-06-23 472 /*
e1c92149 Daniel Lezcano 2017-06-23 473 * This function must be called with the local irq disabled in
e1c92149 Daniel Lezcano 2017-06-23 474 * order to prevent the timings circular buffer to be updated
e1c92149 Daniel Lezcano 2017-06-23 475 * while we are reading it.
e1c92149 Daniel Lezcano 2017-06-23 476 */
a934d4d1 Frederic Weisbecker 2017-11-06 477 lockdep_assert_irqs_disabled();
e1c92149 Daniel Lezcano 2017-06-23 478
bbba0e7c Daniel Lezcano 2019-03-28 479 if (!irqts->count)
bbba0e7c Daniel Lezcano 2019-03-28 480 return next_evt;
bbba0e7c Daniel Lezcano 2019-03-28 481
bbba0e7c Daniel Lezcano 2019-03-28 482 /*
bbba0e7c Daniel Lezcano 2019-03-28 483 * Number of elements in the circular buffer: If it happens it
bbba0e7c Daniel Lezcano 2019-03-28 484 * was flushed before, then the number of elements could be
bbba0e7c Daniel Lezcano 2019-03-28 485 * smaller than IRQ_TIMINGS_SIZE, so the count is used,
bbba0e7c Daniel Lezcano 2019-03-28 486 * otherwise the array size is used as we wrapped. The index
bbba0e7c Daniel Lezcano 2019-03-28 487 * begins from zero when we did not wrap. That could be done
bbba0e7c Daniel Lezcano 2019-03-28 488 * in a nicer way with the proper circular array structure
bbba0e7c Daniel Lezcano 2019-03-28 489 * type but with the cost of extra computation in the
bbba0e7c Daniel Lezcano 2019-03-28 490 * interrupt handler hot path. We choose efficiency.
bbba0e7c Daniel Lezcano 2019-03-28 491 *
bbba0e7c Daniel Lezcano 2019-03-28 492 * Inject measured irq/timestamp to the pattern prediction
bbba0e7c Daniel Lezcano 2019-03-28 493 * model while decrementing the counter because we consume the
bbba0e7c Daniel Lezcano 2019-03-28 494 * data from our circular buffer.
bbba0e7c Daniel Lezcano 2019-03-28 495 */
bbba0e7c Daniel Lezcano 2019-03-28 496
bbba0e7c Daniel Lezcano 2019-03-28 497 i = (irqts->count & IRQ_TIMINGS_MASK) - 1;
bbba0e7c Daniel Lezcano 2019-03-28 498 irqts->count = min(IRQ_TIMINGS_SIZE, irqts->count);
bbba0e7c Daniel Lezcano 2019-03-28 499
bbba0e7c Daniel Lezcano 2019-03-28 500 for (; irqts->count > 0; irqts->count--, i = (i + 1) & IRQ_TIMINGS_MASK) {
bbba0e7c Daniel Lezcano 2019-03-28 501 irq = irq_timing_decode(irqts->values[i], &ts);
bbba0e7c Daniel Lezcano 2019-03-28 @502 s = idr_find(&irqt_stats, irq);
bbba0e7c Daniel Lezcano 2019-03-28 503 if (s)
bbba0e7c Daniel Lezcano 2019-03-28 504 irq_timings_store(irq, this_cpu_ptr(s), ts);
bbba0e7c Daniel Lezcano 2019-03-28 505 }
bbba0e7c Daniel Lezcano 2019-03-28 506
bbba0e7c Daniel Lezcano 2019-03-28 507 /*
bbba0e7c Daniel Lezcano 2019-03-28 508 * Look in the list of interrupts' statistics, the earliest
bbba0e7c Daniel Lezcano 2019-03-28 509 * next event.
bbba0e7c Daniel Lezcano 2019-03-28 510 */
bbba0e7c Daniel Lezcano 2019-03-28 @511 idr_for_each_entry(&irqt_stats, s, i) {
bbba0e7c Daniel Lezcano 2019-03-28 512
bbba0e7c Daniel Lezcano 2019-03-28 513 irqs = this_cpu_ptr(s);
bbba0e7c Daniel Lezcano 2019-03-28 514
bbba0e7c Daniel Lezcano 2019-03-28 515 ts = __irq_timings_next_event(irqs, i, now);
bbba0e7c Daniel Lezcano 2019-03-28 516 if (ts <= now)
bbba0e7c Daniel Lezcano 2019-03-28 517 return now;
bbba0e7c Daniel Lezcano 2019-03-28 518
bbba0e7c Daniel Lezcano 2019-03-28 519 if (ts < next_evt)
bbba0e7c Daniel Lezcano 2019-03-28 520 next_evt = ts;
bbba0e7c Daniel Lezcano 2019-03-28 521 }
bbba0e7c Daniel Lezcano 2019-03-28 522
bbba0e7c Daniel Lezcano 2019-03-28 523 return next_evt;
e1c92149 Daniel Lezcano 2017-06-23 524 }
e1c92149 Daniel Lezcano 2017-06-23 525
e1c92149 Daniel Lezcano 2017-06-23 526 void irq_timings_free(int irq)
e1c92149 Daniel Lezcano 2017-06-23 527 {
e1c92149 Daniel Lezcano 2017-06-23 528 struct irqt_stat __percpu *s;
e1c92149 Daniel Lezcano 2017-06-23 529
e1c92149 Daniel Lezcano 2017-06-23 530 s = idr_find(&irqt_stats, irq);
e1c92149 Daniel Lezcano 2017-06-23 531 if (s) {
e1c92149 Daniel Lezcano 2017-06-23 532 free_percpu(s);
e1c92149 Daniel Lezcano 2017-06-23 533 idr_remove(&irqt_stats, irq);
e1c92149 Daniel Lezcano 2017-06-23 534 }
e1c92149 Daniel Lezcano 2017-06-23 535 }
e1c92149 Daniel Lezcano 2017-06-23 536
e1c92149 Daniel Lezcano 2017-06-23 537 int irq_timings_alloc(int irq)
e1c92149 Daniel Lezcano 2017-06-23 538 {
e1c92149 Daniel Lezcano 2017-06-23 539 struct irqt_stat __percpu *s;
e1c92149 Daniel Lezcano 2017-06-23 540 int id;
e1c92149 Daniel Lezcano 2017-06-23 541
e1c92149 Daniel Lezcano 2017-06-23 542 /*
e1c92149 Daniel Lezcano 2017-06-23 543 * Some platforms can have the same private interrupt per cpu,
e1c92149 Daniel Lezcano 2017-06-23 544 * so this function may be be called several times with the
e1c92149 Daniel Lezcano 2017-06-23 545 * same interrupt number. Just bail out in case the per cpu
e1c92149 Daniel Lezcano 2017-06-23 546 * stat structure is already allocated.
e1c92149 Daniel Lezcano 2017-06-23 547 */
e1c92149 Daniel Lezcano 2017-06-23 548 s = idr_find(&irqt_stats, irq);
e1c92149 Daniel Lezcano 2017-06-23 549 if (s)
e1c92149 Daniel Lezcano 2017-06-23 550 return 0;
e1c92149 Daniel Lezcano 2017-06-23 551
e1c92149 Daniel Lezcano 2017-06-23 552 s = alloc_percpu(*s);
e1c92149 Daniel Lezcano 2017-06-23 553 if (!s)
e1c92149 Daniel Lezcano 2017-06-23 554 return -ENOMEM;
e1c92149 Daniel Lezcano 2017-06-23 555
e1c92149 Daniel Lezcano 2017-06-23 556 idr_preload(GFP_KERNEL);
e1c92149 Daniel Lezcano 2017-06-23 @557 id = idr_alloc(&irqt_stats, s, irq, irq + 1, GFP_NOWAIT);
:::::: The code at line 502 was first introduced by commit
:::::: bbba0e7c5cdadb47a91edea1d5cd0caadbbb016f genirq/timings: Add array suffix computation code
:::::: TO: Daniel Lezcano <daniel.lezcano@...aro.org>
:::::: CC: Thomas Gleixner <tglx@...utronix.de>
---
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