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authorDavid Miller <davem@davemloft.net>2012-10-08 16:34:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:23:05 +0900
commitc460bec78d9257a54bcc5f9d5fadf89f8c70dbd1 (patch)
tree5928e8f429f1f792f0972811539af0dfe1007ac1 /arch/sparc/include/asm/mmu_64.h
parent56a70b8c6acc73f5d9ec383d840909dd9e63c865 (diff)
downloadop-kernel-dev-c460bec78d9257a54bcc5f9d5fadf89f8c70dbd1.zip
op-kernel-dev-c460bec78d9257a54bcc5f9d5fadf89f8c70dbd1.tar.gz
sparc64: Eliminate PTE table memory wastage.
We've split up the PTE tables so that they take up half a page instead of a full page. This is in order to facilitate transparent huge page support, which works much better if our PMDs cover 4MB instead of 8MB. What we do is have a one-behind cache for PTE table allocations in the mm struct. This logic triggers only on allocations. For example, we don't try to keep track of free'd up page table blocks in the style that the s390 port does. There were only two slightly annoying aspects to this change: 1) Changing pgtable_t to be a "pte_t *". There's all of this special logic in the TLB free paths that needed adjustments, as did the PMD populate interfaces. 2) init_new_context() needs to zap the pointer, since the mm struct just gets copied from the parent on fork. Signed-off-by: David S. Miller <davem@davemloft.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/sparc/include/asm/mmu_64.h')
-rw-r--r--arch/sparc/include/asm/mmu_64.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/sparc/include/asm/mmu_64.h b/arch/sparc/include/asm/mmu_64.h
index 5fb97e1..31977c8 100644
--- a/arch/sparc/include/asm/mmu_64.h
+++ b/arch/sparc/include/asm/mmu_64.h
@@ -93,6 +93,7 @@ typedef struct {
spinlock_t lock;
unsigned long sparc64_ctx_val;
unsigned long huge_pte_count;
+ struct page *pgtable_page;
struct tsb_config tsb_block[MM_NUM_TSBS];
struct hv_tsb_descr tsb_descr[MM_NUM_TSBS];
} mm_context_t;
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