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[PATCH] sched: cleanup context switch locking

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Instead of requiring architecture code to interact with the scheduler's
locking implementation, provide a couple of defines that can be used by the
architecture to request runqueue unlocked context switches, and ask for
interrupts to be enabled over the context switch.

Also replaces the "switch_lock" used by these architectures with an oncpu
flag (note, not a potentially slow bitflag).  This eliminates one bus
locked memory operation when context switching, and simplifies the
task_running function.

Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Nick Piggin
2005-06-25 14:57:23 -07:00
committed by Linus Torvalds
parent 48c08d3f8f
commit 4866cde064
9 changed files with 131 additions and 97 deletions
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10
include/asm-ia64/system.h
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@@ -183,8 +183,6 @@ do { \
#ifdef __KERNEL__
#define prepare_to_switch() do { } while(0)
#ifdef CONFIG_IA32_SUPPORT
# define IS_IA32_PROCESS(regs) (ia64_psr(regs)->is != 0)
#else
@@ -274,13 +272,7 @@ extern void ia64_load_extra (struct task_struct *task);
* of that CPU which will not be released, because there we wait for the
* tasklist_lock to become available.
*/
#define prepare_arch_switch(rq, next) \
do { \
spin_lock(&(next)->switch_lock); \
spin_unlock(&(rq)->lock); \
} while (0)
#define finish_arch_switch(rq, prev) spin_unlock_irq(&(prev)->switch_lock)
#define task_running(rq, p) ((rq)->curr == (p) || spin_is_locked(&(p)->switch_lock))
#define __ARCH_WANT_UNLOCKED_CTXSW
#define ia64_platform_is(x) (strcmp(x, platform_name) == 0)