diff options
Diffstat (limited to 'Documentation/scheduler/sched-arch.txt')
| -rw-r--r-- | Documentation/scheduler/sched-arch.txt | 19 |
1 files changed, 2 insertions, 17 deletions
diff --git a/Documentation/scheduler/sched-arch.txt b/Documentation/scheduler/sched-arch.txt index d43dbcbd163..a2f27bbf2cb 100644 --- a/Documentation/scheduler/sched-arch.txt +++ b/Documentation/scheduler/sched-arch.txt @@ -8,7 +8,7 @@ Context switch By default, the switch_to arch function is called with the runqueue locked. This is usually not a problem unless switch_to may need to take the runqueue lock. This is usually due to a wake up operation in -the context switch. See arch/ia64/include/asm/system.h for an example. +the context switch. See arch/ia64/include/asm/switch_to.h for an example. To request the scheduler call switch_to with the runqueue unlocked, you must `#define __ARCH_WANT_UNLOCKED_CTXSW` in a header file @@ -17,16 +17,6 @@ you must `#define __ARCH_WANT_UNLOCKED_CTXSW` in a header file Unlocked context switches introduce only a very minor performance penalty to the core scheduler implementation in the CONFIG_SMP case. -2. Interrupt status -By default, the switch_to arch function is called with interrupts -disabled. Interrupts may be enabled over the call if it is likely to -introduce a significant interrupt latency by adding the line -`#define __ARCH_WANT_INTERRUPTS_ON_CTXSW` in the same place as for -unlocked context switches. This define also implies -`__ARCH_WANT_UNLOCKED_CTXSW`. See arch/arm/include/asm/system.h for an -example. - - CPU idle ======== Your cpu_idle routines need to obey the following rules: @@ -66,7 +56,7 @@ Your cpu_idle routines need to obey the following rules: barrier issued (followed by a test of need_resched with interrupts disabled, as explained in 3). -arch/i386/kernel/process.c has examples of both polling and +arch/x86/kernel/process.c has examples of both polling and sleeping idle functions. @@ -75,11 +65,6 @@ Possible arch/ problems Possible arch problems I found (and either tried to fix or didn't): -h8300 - Is such sleeping racy vs interrupts? (See #4a). - The H8/300 manual I found indicates yes, however disabling IRQs - over the sleep mean only NMIs can wake it up, so can't fix easily - without doing spin waiting. - ia64 - is safe_halt call racy vs interrupts? (does it sleep?) (See #4a) sh64 - Is sleeping racy vs interrupts? (See #4a) |