From b8f8c3cf0a4ac0632ec3f0e15e9dc0c29de917af Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 18 Jul 2008 17:27:28 +0200 Subject: nohz: prevent tick stop outside of the idle loop Jack Ren and Eric Miao tracked down the following long standing problem in the NOHZ code: scheduler switch to idle task enable interrupts Window starts here ----> interrupt happens (does not set NEED_RESCHED) irq_exit() stops the tick ----> interrupt happens (does set NEED_RESCHED) return from schedule() cpu_idle(): preempt_disable(); Window ends here The interrupts can happen at any point inside the race window. The first interrupt stops the tick, the second one causes the scheduler to rerun and switch away from idle again and we end up with the tick disabled. The fact that it needs two interrupts where the first one does not set NEED_RESCHED and the second one does made the bug obscure and extremly hard to reproduce and analyse. Kudos to Jack and Eric. Solution: Limit the NOHZ functionality to the idle loop to make sure that we can not run into such a situation ever again. cpu_idle() { preempt_disable(); while(1) { tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we are in the idle loop while (!need_resched()) halt(); tick_nohz_restart_sched_tick(); <- disables NOHZ mode preempt_enable_no_resched(); schedule(); preempt_disable(); } } In hindsight we should have done this forever, but ... /me grabs a large brown paperbag. Debugged-by: Jack Ren , Debugged-by: eric miao Signed-off-by: Thomas Gleixner --- arch/avr32/kernel/process.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/avr32/kernel/process.c') diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c index 6cf9df176274..ff820a9e743a 100644 --- a/arch/avr32/kernel/process.c +++ b/arch/avr32/kernel/process.c @@ -31,7 +31,7 @@ void cpu_idle(void) { /* endless idle loop with no priority at all */ while (1) { - tick_nohz_stop_sched_tick(); + tick_nohz_stop_sched_tick(1); while (!need_resched()) cpu_idle_sleep(); tick_nohz_restart_sched_tick(); -- cgit v1.2.3 From 3663b736a5083b3bce74520b637f630f01f66a7f Mon Sep 17 00:00:00 2001 From: Haavard Skinnemoen Date: Tue, 5 Aug 2008 13:57:38 +0200 Subject: avr32: Use instead of Update all avr32-specific files to use the new platform-specific header locations. Drivers shared with ARM are left alone for now. Signed-off-by: Haavard Skinnemoen --- arch/avr32/boards/atngw100/flash.c | 2 +- arch/avr32/boards/atngw100/setup.c | 8 ++++---- arch/avr32/boards/atstk1000/atstk1002.c | 10 +++++----- arch/avr32/boards/atstk1000/atstk1003.c | 8 ++++---- arch/avr32/boards/atstk1000/atstk1004.c | 8 ++++---- arch/avr32/boards/atstk1000/flash.c | 2 +- arch/avr32/boards/atstk1000/setup.c | 6 +++--- arch/avr32/include/asm/gpio.h | 2 +- arch/avr32/include/asm/io.h | 2 +- arch/avr32/include/asm/irq.h | 2 +- arch/avr32/kernel/process.c | 2 +- arch/avr32/kernel/setup.c | 4 ++-- arch/avr32/kernel/time.c | 2 +- arch/avr32/mach-at32ap/at32ap700x.c | 8 ++++---- arch/avr32/mach-at32ap/hsmc.c | 2 +- arch/avr32/mach-at32ap/pio.c | 2 +- arch/avr32/mach-at32ap/pm-at32ap700x.S | 2 +- arch/avr32/mach-at32ap/pm.c | 4 ++-- drivers/ata/pata_at32.c | 4 ++-- drivers/mmc/host/atmel-mci.c | 2 +- 20 files changed, 41 insertions(+), 41 deletions(-) (limited to 'arch/avr32/kernel/process.c') diff --git a/arch/avr32/boards/atngw100/flash.c b/arch/avr32/boards/atngw100/flash.c index b07ae63aa548..55ccc9ce4892 100644 --- a/arch/avr32/boards/atngw100/flash.c +++ b/arch/avr32/boards/atngw100/flash.c @@ -13,7 +13,7 @@ #include #include -#include +#include static struct smc_timing flash_timing __initdata = { .ncs_read_setup = 0, diff --git a/arch/avr32/boards/atngw100/setup.c b/arch/avr32/boards/atngw100/setup.c index c7fe94d03a1e..670c87b2db12 100644 --- a/arch/avr32/boards/atngw100/setup.c +++ b/arch/avr32/boards/atngw100/setup.c @@ -23,10 +23,10 @@ #include #include -#include -#include -#include -#include +#include +#include +#include +#include /* Oscillator frequencies. These are board-specific */ unsigned long at32_board_osc_rates[3] = { diff --git a/arch/avr32/boards/atstk1000/atstk1002.c b/arch/avr32/boards/atstk1000/atstk1002.c index 8538ba75ef92..b33542b97563 100644 --- a/arch/avr32/boards/atstk1000/atstk1002.c +++ b/arch/avr32/boards/atstk1000/atstk1002.c @@ -23,10 +23,10 @@ #include #include -#include -#include -#include -#include +#include +#include +#include +#include #include "atstk1000.h" @@ -49,7 +49,7 @@ unsigned long at32_board_osc_rates[3] = { */ #ifdef CONFIG_BOARD_ATSTK1006 #include -#include +#include static struct smc_timing nand_timing __initdata = { .ncs_read_setup = 0, diff --git a/arch/avr32/boards/atstk1000/atstk1003.c b/arch/avr32/boards/atstk1000/atstk1003.c index 591fc73b554a..0cf664174c17 100644 --- a/arch/avr32/boards/atstk1000/atstk1003.c +++ b/arch/avr32/boards/atstk1000/atstk1003.c @@ -20,10 +20,10 @@ #include -#include -#include -#include -#include +#include +#include +#include +#include #include "atstk1000.h" diff --git a/arch/avr32/boards/atstk1000/atstk1004.c b/arch/avr32/boards/atstk1000/atstk1004.c index d9c5e0a21256..50a5273e5916 100644 --- a/arch/avr32/boards/atstk1000/atstk1004.c +++ b/arch/avr32/boards/atstk1000/atstk1004.c @@ -22,10 +22,10 @@ #include -#include -#include -#include -#include +#include +#include +#include +#include #include "atstk1000.h" diff --git a/arch/avr32/boards/atstk1000/flash.c b/arch/avr32/boards/atstk1000/flash.c index 3d0a102ad45e..6e4d561977ff 100644 --- a/arch/avr32/boards/atstk1000/flash.c +++ b/arch/avr32/boards/atstk1000/flash.c @@ -13,7 +13,7 @@ #include #include -#include +#include static struct smc_timing flash_timing __initdata = { .ncs_read_setup = 0, diff --git a/arch/avr32/boards/atstk1000/setup.c b/arch/avr32/boards/atstk1000/setup.c index 8bedf93876a3..2d6b560115d9 100644 --- a/arch/avr32/boards/atstk1000/setup.c +++ b/arch/avr32/boards/atstk1000/setup.c @@ -18,9 +18,9 @@ #include -#include -#include -#include +#include +#include +#include #include "atstk1000.h" diff --git a/arch/avr32/include/asm/gpio.h b/arch/avr32/include/asm/gpio.h index 19e8ccc77db3..b771f7105964 100644 --- a/arch/avr32/include/asm/gpio.h +++ b/arch/avr32/include/asm/gpio.h @@ -1,6 +1,6 @@ #ifndef __ASM_AVR32_GPIO_H #define __ASM_AVR32_GPIO_H -#include +#include #endif /* __ASM_AVR32_GPIO_H */ diff --git a/arch/avr32/include/asm/io.h b/arch/avr32/include/asm/io.h index 8be7ea9c9047..a520f77ead96 100644 --- a/arch/avr32/include/asm/io.h +++ b/arch/avr32/include/asm/io.h @@ -8,7 +8,7 @@ #include #include -#include +#include /* virt_to_phys will only work when address is in P1 or P2 */ static __inline__ unsigned long virt_to_phys(volatile void *address) diff --git a/arch/avr32/include/asm/irq.h b/arch/avr32/include/asm/irq.h index c563b7720c1a..6fa8913f8548 100644 --- a/arch/avr32/include/asm/irq.h +++ b/arch/avr32/include/asm/irq.h @@ -3,7 +3,7 @@ #define NR_INTERNAL_IRQS 64 -#include +#include #ifndef NR_IRQS #define NR_IRQS (NR_INTERNAL_IRQS) diff --git a/arch/avr32/kernel/process.c b/arch/avr32/kernel/process.c index ff820a9e743a..2c08ac992ac3 100644 --- a/arch/avr32/kernel/process.c +++ b/arch/avr32/kernel/process.c @@ -18,7 +18,7 @@ #include #include -#include +#include void (*pm_power_off)(void) = NULL; EXPORT_SYMBOL(pm_power_off); diff --git a/arch/avr32/kernel/setup.c b/arch/avr32/kernel/setup.c index ce48c14f4349..d8e623c426c1 100644 --- a/arch/avr32/kernel/setup.c +++ b/arch/avr32/kernel/setup.c @@ -26,8 +26,8 @@ #include #include -#include -#include +#include +#include extern int root_mountflags; diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c index 7e7f32771ae1..283481d74a5b 100644 --- a/arch/avr32/kernel/time.c +++ b/arch/avr32/kernel/time.c @@ -15,7 +15,7 @@ #include -#include +#include static cycle_t read_cycle_count(void) diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c index 1617048c86c5..92bfb4d8ae45 100644 --- a/arch/avr32/mach-at32ap/at32ap700x.c +++ b/arch/avr32/mach-at32ap/at32ap700x.c @@ -20,10 +20,10 @@ #include #include -#include -#include -#include -#include +#include +#include +#include +#include #include