Messages in this thread Patch in this message | | | Date | Thu, 8 Nov 2007 10:50:00 -0800 (PST) | From | Christoph Lameter <> | Subject | Re: [patch 01/28] cpu alloc: The allocator |
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On Thu, 8 Nov 2007, Christoph Lameter wrote:
> > Also, looking at the lock usage, this thing is not IRQ safe, so it > > should not be called from hardirq context. Please document this.
Well I went the other way and made it work like the slab allocators.
cpu_alloc: Make it irq safe
Use the same method as used in SLAB/SLUB to make the allocator interrupt safe. disable interrupts when allocator metadata is processed. Reenable interrupts during page allocator calls if __GFP_WAIT is set in the flags passed to the allocator.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
--- mm/cpu_alloc.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-)
Index: linux-2.6/mm/cpu_alloc.c =================================================================== --- linux-2.6.orig/mm/cpu_alloc.c 2007-11-07 16:49:40.069701326 -0800 +++ linux-2.6/mm/cpu_alloc.c 2007-11-08 10:45:43.172294260 -0800 @@ -186,6 +186,8 @@ static int expand_cpu_area(gfp_t flags) goto out; spin_unlock(&cpu_alloc_map_lock); + if (flags & __GFP_WAIT) + local_irq_enable(); /* * Determine the size of the bit map needed @@ -212,6 +214,8 @@ static int expand_cpu_area(gfp_t flags) goto out; } + if (flags & __GFP_WAIT) + local_irq_disable(); spin_lock(&cpu_alloc_map_lock); /* @@ -312,10 +316,11 @@ void *cpu_alloc(unsigned long size, gfp_ void *ptr; int first; unsigned long map_size; + unsigned long flags; BUG_ON(gfpflags & ~(GFP_RECLAIM_MASK | __GFP_ZERO)); - spin_lock(&cpu_alloc_map_lock); + spin_lock_irqsave(&cpu_alloc_map_lock, flags); restart: map_size = PAGE_SIZE << cpu_alloc_map_order; @@ -358,7 +363,7 @@ restart: units_free -= units; __count_vm_events(CPU_BYTES, units * UNIT_SIZE); - spin_unlock(&cpu_alloc_map_lock); + spin_unlock_irqrestore(&cpu_alloc_map_lock, flags); ptr = cpu_area + start * UNIT_SIZE; @@ -372,7 +377,7 @@ restart: return ptr; out_of_memory: - spin_unlock(&cpu_alloc_map_lock); + spin_unlock_irqrestore(&cpu_alloc_map_lock, flags); return NULL; } EXPORT_SYMBOL(cpu_alloc); @@ -386,13 +391,14 @@ void cpu_free(void *start, unsigned long int units = size_to_units(size); int index; u8 *p = start; + unsigned long flags; BUG_ON(p < cpu_area); index = (p - cpu_area) / UNIT_SIZE; BUG_ON(!test_bit(index, cpu_alloc_map) || index >= units_total); - spin_lock(&cpu_alloc_map_lock); + spin_lock_irqsave(&cpu_alloc_map_lock, flags); clear_map(index, units); units_free += units; @@ -400,6 +406,6 @@ void cpu_free(void *start, unsigned long if (index < first_free) first_free = index; - spin_unlock(&cpu_alloc_map_lock); + spin_unlock_irqrestore(&cpu_alloc_map_lock, flags); } EXPORT_SYMBOL(cpu_free); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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