Revision 2bbd00aef0671bfe3c2ca5ba67097246257de125 authored by Johannes Weiner on 26 February 2021, 01:16:47 UTC, committed by Linus Torvalds on 26 February 2021, 17:41:00 UTC
On NOHZ, the periodic vmstat flushers on each CPU can go to sleep and won't wake up until stat changes are detected in the per-cpu deltas of the zone vmstat counters. In commit 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats") per-node counters were introduced, and subsequently most stats were moved from the zone to the node level. However, the node counters weren't added to the NOHZ wakeup detection. In theory this can cause per-cpu errors to remain in the user-reported stats indefinitely. In practice this only affects a handful of sub counters (file_mapped, dirty and writeback e.g.) because other page state changes at the node level likely involve a change at the zone level as well (alloc and free, lru ops). Also, nobody has complained. Fix it up for completeness: wake up vmstat refreshing on node changes. Also remove the BUILD_BUG_ONs that assert counter size; we haven't relied on it since we added sizeof() to the range calculation in commit 13c9aaf7fa01 ("mm/vmstat.c: fix NUMA statistics updates"). Link: https://lkml.kernel.org/r/20210202184342.118513-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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gpio-sch.c
// SPDX-License-Identifier: GPL-2.0
/*
* GPIO interface for Intel Poulsbo SCH
*
* Copyright (c) 2010 CompuLab Ltd
* Author: Denis Turischev <denis@compulab.co.il>
*/
#include <linux/acpi.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci_ids.h>
#include <linux/platform_device.h>
#define GEN 0x00
#define GIO 0x04
#define GLV 0x08
struct sch_gpio {
struct gpio_chip chip;
spinlock_t lock;
unsigned short iobase;
unsigned short resume_base;
};
static unsigned int sch_gpio_offset(struct sch_gpio *sch, unsigned int gpio,
unsigned int reg)
{
unsigned int base = 0;
if (gpio >= sch->resume_base) {
gpio -= sch->resume_base;
base += 0x20;
}
return base + reg + gpio / 8;
}
static unsigned int sch_gpio_bit(struct sch_gpio *sch, unsigned int gpio)
{
if (gpio >= sch->resume_base)
gpio -= sch->resume_base;
return gpio % 8;
}
static int sch_gpio_reg_get(struct sch_gpio *sch, unsigned int gpio, unsigned int reg)
{
unsigned short offset, bit;
u8 reg_val;
offset = sch_gpio_offset(sch, gpio, reg);
bit = sch_gpio_bit(sch, gpio);
reg_val = !!(inb(sch->iobase + offset) & BIT(bit));
return reg_val;
}
static void sch_gpio_reg_set(struct sch_gpio *sch, unsigned int gpio, unsigned int reg,
int val)
{
unsigned short offset, bit;
u8 reg_val;
offset = sch_gpio_offset(sch, gpio, reg);
bit = sch_gpio_bit(sch, gpio);
reg_val = inb(sch->iobase + offset);
if (val)
outb(reg_val | BIT(bit), sch->iobase + offset);
else
outb((reg_val & ~BIT(bit)), sch->iobase + offset);
}
static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned int gpio_num)
{
struct sch_gpio *sch = gpiochip_get_data(gc);
spin_lock(&sch->lock);
sch_gpio_reg_set(sch, gpio_num, GIO, 1);
spin_unlock(&sch->lock);
return 0;
}
static int sch_gpio_get(struct gpio_chip *gc, unsigned int gpio_num)
{
struct sch_gpio *sch = gpiochip_get_data(gc);
return sch_gpio_reg_get(sch, gpio_num, GLV);
}
static void sch_gpio_set(struct gpio_chip *gc, unsigned int gpio_num, int val)
{
struct sch_gpio *sch = gpiochip_get_data(gc);
spin_lock(&sch->lock);
sch_gpio_reg_set(sch, gpio_num, GLV, val);
spin_unlock(&sch->lock);
}
static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned int gpio_num,
int val)
{
struct sch_gpio *sch = gpiochip_get_data(gc);
spin_lock(&sch->lock);
sch_gpio_reg_set(sch, gpio_num, GIO, 0);
spin_unlock(&sch->lock);
/*
* according to the datasheet, writing to the level register has no
* effect when GPIO is programmed as input.
* Actually the the level register is read-only when configured as input.
* Thus presetting the output level before switching to output is _NOT_ possible.
* Hence we set the level after configuring the GPIO as output.
* But we cannot prevent a short low pulse if direction is set to high
* and an external pull-up is connected.
*/
sch_gpio_set(gc, gpio_num, val);
return 0;
}
static int sch_gpio_get_direction(struct gpio_chip *gc, unsigned int gpio_num)
{
struct sch_gpio *sch = gpiochip_get_data(gc);
if (sch_gpio_reg_get(sch, gpio_num, GIO))
return GPIO_LINE_DIRECTION_IN;
return GPIO_LINE_DIRECTION_OUT;
}
static const struct gpio_chip sch_gpio_chip = {
.label = "sch_gpio",
.owner = THIS_MODULE,
.direction_input = sch_gpio_direction_in,
.get = sch_gpio_get,
.direction_output = sch_gpio_direction_out,
.set = sch_gpio_set,
.get_direction = sch_gpio_get_direction,
};
static int sch_gpio_probe(struct platform_device *pdev)
{
struct sch_gpio *sch;
struct resource *res;
sch = devm_kzalloc(&pdev->dev, sizeof(*sch), GFP_KERNEL);
if (!sch)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!res)
return -EBUSY;
if (!devm_request_region(&pdev->dev, res->start, resource_size(res),
pdev->name))
return -EBUSY;
spin_lock_init(&sch->lock);
sch->iobase = res->start;
sch->chip = sch_gpio_chip;
sch->chip.label = dev_name(&pdev->dev);
sch->chip.parent = &pdev->dev;
switch (pdev->id) {
case PCI_DEVICE_ID_INTEL_SCH_LPC:
sch->resume_base = 10;
sch->chip.ngpio = 14;
/*
* GPIO[6:0] enabled by default
* GPIO7 is configured by the CMC as SLPIOVR
* Enable GPIO[9:8] core powered gpios explicitly
*/
sch_gpio_reg_set(sch, 8, GEN, 1);
sch_gpio_reg_set(sch, 9, GEN, 1);
/*
* SUS_GPIO[2:0] enabled by default
* Enable SUS_GPIO3 resume powered gpio explicitly
*/
sch_gpio_reg_set(sch, 13, GEN, 1);
break;
case PCI_DEVICE_ID_INTEL_ITC_LPC:
sch->resume_base = 5;
sch->chip.ngpio = 14;
break;
case PCI_DEVICE_ID_INTEL_CENTERTON_ILB:
sch->resume_base = 21;
sch->chip.ngpio = 30;
break;
case PCI_DEVICE_ID_INTEL_QUARK_X1000_ILB:
sch->resume_base = 2;
sch->chip.ngpio = 8;
break;
default:
return -ENODEV;
}
platform_set_drvdata(pdev, sch);
return devm_gpiochip_add_data(&pdev->dev, &sch->chip, sch);
}
static struct platform_driver sch_gpio_driver = {
.driver = {
.name = "sch_gpio",
},
.probe = sch_gpio_probe,
};
module_platform_driver(sch_gpio_driver);
MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
MODULE_DESCRIPTION("GPIO interface for Intel Poulsbo SCH");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:sch_gpio");
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