diff options
| author | Paul Mackerras <paulus@samba.org> | 2006-06-15 10:45:18 +1000 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2006-06-15 10:45:18 +1000 |
| commit | bf72aeba2ffef599d1d386425c9e46b82be657cd (patch) | |
| tree | ead8e5111dbcfa22e156999d1bb8a96e50f06fef /arch/powerpc/mm/tlb_64.c | |
| parent | 31925323b1b51bb65db729e029472a8b1f635b7d (diff) | |
| download | linux-bf72aeba2ffef599d1d386425c9e46b82be657cd.tar.gz | |
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.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/powerpc/mm/tlb_64.c b/arch/powerpc/mm/tlb_64.c index f734b11566c2a..e7449b068c825 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 |