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authorPaul Mackerras <paulus@samba.org>2006-06-15 10:45:18 +1000
committerPaul Mackerras <paulus@samba.org>2006-06-15 10:45:18 +1000
commitbf72aeba2ffef599d1d386425c9e46b82be657cd (patch)
treeead8e5111dbcfa22e156999d1bb8a96e50f06fef /arch/powerpc/mm/tlb_64.c
parent31925323b1b51bb65db729e029472a8b1f635b7d (diff)
powerpc: Use 64k pages without needing cache-inhibited large pages
Some POWER5+ machines can do 64k hardware pages for normal memory but not for cache-inhibited pages. This patch lets us use 64k hardware pages for most user processes on such machines (assuming the kernel has been configured with CONFIG_PPC_64K_PAGES=y). User processes start out using 64k pages and get switched to 4k pages if they use any non-cacheable mappings. With this, we use 64k pages for the vmalloc region and 4k pages for the imalloc region. If anything creates a non-cacheable mapping in the vmalloc region, the vmalloc region will get switched to 4k pages. I don't know of any driver other than the DRM that would do this, though, and these machines don't have AGP. When a region gets switched from 64k pages to 4k pages, we do not have to clear out all the 64k HPTEs from the hash table immediately. We use the _PAGE_COMBO bit in the Linux PTE to indicate whether the page was hashed in as a 64k page or a set of 4k pages. If hash_page is trying to insert a 4k page for a Linux PTE and it sees that it has already been inserted as a 64k page, it first invalidates the 64k HPTE before inserting the 4k HPTE. The hash invalidation routines also use the _PAGE_COMBO bit, to determine whether to look for a 64k HPTE or a set of 4k HPTEs to remove. With those two changes, we can tolerate a mix of 4k and 64k HPTEs in the hash table, and they will all get removed when the address space is torn down. Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/mm/tlb_64.c')
-rw-r--r--arch/powerpc/mm/tlb_64.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/powerpc/mm/tlb_64.c b/arch/powerpc/mm/tlb_64.c
index f734b11566c..e7449b068c8 100644
--- a/arch/powerpc/mm/tlb_64.c
+++ b/arch/powerpc/mm/tlb_64.c
@@ -131,7 +131,7 @@ void hpte_update(struct mm_struct *mm, unsigned long addr,
{
struct ppc64_tlb_batch *batch = &__get_cpu_var(ppc64_tlb_batch);
unsigned long vsid;
- unsigned int psize = mmu_virtual_psize;
+ unsigned int psize;
int i;
i = batch->index;
@@ -148,7 +148,8 @@ void hpte_update(struct mm_struct *mm, unsigned long addr,
#else
BUG();
#endif
- }
+ } else
+ psize = pte_pagesize_index(pte);
/*
* This can happen when we are in the middle of a TLB batch and