Re: [PATCH] zsmalloc: Fix TLB coherency and build problem

From: Russell King - ARM Linux
Date: Fri Feb 01 2013 - 09:05:01 EST


On Mon, Jan 28, 2013 at 10:00:08AM +0900, Minchan Kim wrote:
> @@ -663,7 +661,7 @@ static inline void __zs_unmap_object(struct mapping_area *area,
>
> flush_cache_vunmap(addr, end);
> unmap_kernel_range_noflush(addr, PAGE_SIZE * 2);
> - local_flush_tlb_kernel_range(addr, end);
> + flush_tlb_kernel_range(addr, end);

void unmap_kernel_range_noflush(unsigned long addr, unsigned long size)
{
vunmap_page_range(addr, addr + size);
}

void unmap_kernel_range(unsigned long addr, unsigned long size)
{
unsigned long end = addr + size;

flush_cache_vunmap(addr, end);
vunmap_page_range(addr, end);
flush_tlb_kernel_range(addr, end);
}

So, given the above, what would be different between:

unsigned long end = addr + (PAGE_SIZE * 2);

flush_cache_vunmap(addr, end);
unmap_kernel_range_noflush(addr, PAGE_SIZE * 2);
flush_tlb_kernel_range(addr, end);

(which is what it becomes after your change) and

unmap_kernel_range(addr, PAGE_SIZE * 2);

?
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