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SubjectRe: 2.6.0-test9-mm4
William Lee Irwin III <wli@holomorphy.com> wrote:
>>> +#ifdef CONFIG_SMP
>>> +#define smp_local_irq_save(x) local_irq_save(x)
>>> +#define smp_local_irq_restore(x) local_irq_restore(x)
>>> +#define smp_local_irq_disable() local_irq_disable()
>>> +#define smp_local_irq_enable() local_irq_enable()
>>> +#else
[...]

On Wed, Nov 19, 2003 at 01:19:51AM -0800, Andrew Morton wrote:
>> Interesting.

On Wed, Nov 19, 2003 at 01:33:40AM -0800, William Lee Irwin III wrote:
> This was a micro-optimization for UP; the SMP case needs to protect
> against reentry via interrupts due to smp_call_function(). UP can
> just disable preemption. In principle, the two cases could be made
> uniform at the cost of disabling interrupts unnecessarily on UP.

The following, incremental atop the first, removes the smp_local_irq_*()
macros.


-- wli


diff -prauN mm4-2.6.0-test9-2/arch/i386/mm/pgtable.c mm4-2.6.0-test9-3/arch/i386/mm/pgtable.c
--- mm4-2.6.0-test9-2/arch/i386/mm/pgtable.c 2003-11-19 00:22:54.000000000 -0800
+++ mm4-2.6.0-test9-3/arch/i386/mm/pgtable.c 2003-11-19 02:07:13.000000000 -0800
@@ -177,7 +177,7 @@ static inline struct page *pte_alloc_rea
unsigned long flags;
struct page *page = NULL;

- smp_local_irq_save(flags);
+ local_irq_save(flags);
if (tlb->nr_pte_ready) {
int z;
for (z = MAX_ZONE_ID - 1; z >= 0; --z) {
@@ -194,7 +194,7 @@ static inline struct page *pte_alloc_rea
tlb->ready_count[z]--;
tlb->nr_pte_ready--;
}
- smp_local_irq_restore(flags);
+ local_irq_restore(flags);
put_cpu();
return page;
}
@@ -381,7 +381,7 @@ static void shrink_cpu_pagetable_cache(v
high = !!(gfp_mask & __GFP_HIGHMEM);
cpu = get_cpu();
tlb = &per_cpu(mmu_gathers, cpu);
- smp_local_irq_save(flags);
+ local_irq_save(flags);

if (tlb->nr_pte_active)
tlb_flush(tlb);
@@ -417,7 +417,7 @@ static void shrink_cpu_pagetable_cache(v
tlb->ready_count[zone] = 0;
}

- smp_local_irq_restore(flags);
+ local_irq_restore(flags);
put_cpu();
}

diff -prauN mm4-2.6.0-test9-2/include/asm-i386/system.h mm4-2.6.0-test9-3/include/asm-i386/system.h
--- mm4-2.6.0-test9-2/include/asm-i386/system.h 2003-11-19 00:09:43.000000000 -0800
+++ mm4-2.6.0-test9-3/include/asm-i386/system.h 2003-11-19 02:06:11.000000000 -0800
@@ -461,18 +461,6 @@ struct alt_instr {
/* For spinlocks etc */
#define local_irq_save(x) __asm__ __volatile__("pushfl ; popl %0 ; cli":"=g" (x): /* no input */ :"memory")

-#ifdef CONFIG_SMP
-#define smp_local_irq_save(x) local_irq_save(x)
-#define smp_local_irq_restore(x) local_irq_restore(x)
-#define smp_local_irq_disable() local_irq_disable()
-#define smp_local_irq_enable() local_irq_enable()
-#else
-#define smp_local_irq_save(x) do { (void)(x); } while (0)
-#define smp_local_irq_restore(x) do { (void)(x); } while (0)
-#define smp_local_irq_disable() do { } while (0)
-#define smp_local_irq_enable() do { } while (0)
-#endif /* CONFIG_SMP */
-
/*
* disable hlt during certain critical i/o operations
*/
diff -prauN mm4-2.6.0-test9-2/include/asm-i386/tlb.h mm4-2.6.0-test9-3/include/asm-i386/tlb.h
--- mm4-2.6.0-test9-2/include/asm-i386/tlb.h 2003-11-19 00:23:35.000000000 -0800
+++ mm4-2.6.0-test9-3/include/asm-i386/tlb.h 2003-11-19 02:06:58.000000000 -0800
@@ -106,7 +106,7 @@ void tlb_flush_mmu(struct mmu_gather *tl
tlb->need_flush = 0;
tlb_flush(tlb);

- smp_local_irq_save(flags);
+ local_irq_save(flags);

if (tlb->nr_nonpte) {
free_pages_and_swap_cache(tlb->nonpte, tlb->nr_nonpte);
@@ -126,7 +126,7 @@ void tlb_flush_mmu(struct mmu_gather *tl
if (tlb->nr_pte_ready >= NR_PTE)
tlb_flush_ready(tlb);

- smp_local_irq_restore(flags);
+ local_irq_restore(flags);
}

static inline
@@ -163,13 +163,13 @@ void tlb_remove_page(struct mmu_gather *
{
unsigned long flags;

- smp_local_irq_save(flags);
+ local_irq_save(flags);
tlb->need_flush = 1;
if (PagePTE(page))
tlb_remove_pte_page(tlb, page);
else
tlb_remove_nonpte_page(tlb, page);
- smp_local_irq_restore(flags);
+ local_irq_restore(flags);
}

#endif /* _I386_TLB_H */
-
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