[RFC 07/11] ARM: Allocate ZERO_PAGE from highmem
Russell King - ARM Linux
linux at arm.linux.org.uk
Fri Dec 4 09:57:08 EST 2009
On Sun, Oct 25, 2009 at 10:59:08AM +0000, Russell King wrote:
> The zero page does not need to be in low memory, so allocate it from
> high memory.
Unfortunately, this patch is about to be thrown out - mm/shmem.c does
static inline void shmem_swp_balance_unmap(void)
* When passing a pointer to an i_direct entry, to code which
* also handles indirect entries and so will shmem_swp_unmap,
* we must arrange for the preempt count to remain in balance.
* What kmap_atomic of a lowmem page does depends on config
* and architecture, so pretend to kmap_atomic some lowmem page.
(void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
callsite vaddr pteptr *pteptr page_to_phys(page)
kmap_atomic: c007d108 0xfff04000 c046ac10, 0x00000000 0x7800000
kunmap_atomic: c007d88c 0xc1c2a000
kmap_atomic: c007d108 0xfff04000 c046ac10, 0x078002cf 0x7800000
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