From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com>
Change the hugepage directory format so that we can have leaf ptes directly
at page directory avoiding the allocation of hugepage directory.
With the new table format we have 3 cases for pgds and pmds:
(1) invalid (all zeroes)
(2) pointer to next table, as normal; bottom 6 bits == 0
(4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
Instead of storing shift value in hugepd pointer we use mmu_psize_def index
so that we can fit all the supported hugepage size in 4 bits
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/hugetlb.h | 13 +++++++++++--
arch/powerpc/include/asm/mmu-hash64.h | 20 +++++++++++++++++++-
arch/powerpc/include/asm/page.h | 18 +++++-------------
arch/powerpc/include/asm/pgalloc-64.h | 5 ++++-
arch/powerpc/mm/hugetlbpage.c | 23 ++++-------------------
arch/powerpc/mm/init_64.c | 3 +--
6 files changed, 44 insertions(+), 38 deletions(-)
diff --git a/arch/powerpc/include/asm/hugetlb.h
b/arch/powerpc/include/asm/hugetlb.h
index 62e11a3..81f7677 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -9,12 +9,21 @@ extern struct kmem_cache *hugepte_cache;
static inline pte_t *hugepd_page(hugepd_t hpd)
{
BUG_ON(!hugepd_ok(hpd));
- return (pte_t *)((hpd.pd & ~HUGEPD_SHIFT_MASK) | PD_HUGE);
+ /*
+ * We have only four bits to encode, MMU page size
+ */
+ BUILD_BUG_ON((MMU_PAGE_COUNT - 1) > 0xf);
+ return (pte_t *)(hpd.pd & ~HUGEPD_SHIFT_MASK);
+}
+
+static inline unsigned int hugepd_mmu_psize(hugepd_t hpd)
+{
+ return (hpd.pd & HUGEPD_SHIFT_MASK) >> 2;
}
static inline unsigned int hugepd_shift(hugepd_t hpd)
{
- return hpd.pd & HUGEPD_SHIFT_MASK;
+ return mmu_psize_to_shift(hugepd_mmu_psize(hpd));
}
static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
diff --git a/arch/powerpc/include/asm/mmu-hash64.h
b/arch/powerpc/include/asm/mmu-hash64.h
index b59e06f..05895cf 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -21,6 +21,7 @@
* complete pgtable.h but only a portion of it.
*/
#include <asm/pgtable-ppc64.h>
+#include <asm/bug.h>
/*
* Segment table
@@ -159,6 +160,24 @@ struct mmu_psize_def
unsigned long avpnm; /* bits to mask out in AVPN in the HPTE */
unsigned long sllp; /* SLB L||LP (exact mask to use in slbmte) */
};
+extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
+
+static inline int shift_to_mmu_psize(unsigned int shift)
+{
+ int psize;
+
+ for (psize = 0; psize < MMU_PAGE_COUNT; ++psize)
+ if (mmu_psize_defs[psize].shift == shift)
+ return psize;
+ return -1;
+}
+
+static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
+{
+ if (mmu_psize_defs[mmu_psize].shift)
+ return mmu_psize_defs[mmu_psize].shift;
+ BUG();
+}
#endif /* __ASSEMBLY__ */
@@ -193,7 +212,6 @@ static inline int segment_shift(int ssize)
/*
* The current system page and segment sizes
*/
-extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT];
extern int mmu_linear_psize;
extern int mmu_virtual_psize;
extern int mmu_vmalloc_psize;
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index f072e97..b309cf4 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -250,18 +250,6 @@ extern long long virt_phys_offset;
#endif
/*
- * Use the top bit of the higher-level page table entries to indicate whether
- * the entries we point to contain hugepages. This works because we know that
- * the page tables live in kernel space. If we ever decide to support having
- * page tables at arbitrary addresses, this breaks and will have to change.
- */
-#ifdef CONFIG_PPC64
-#define PD_HUGE 0x8000000000000000
-#else
-#define PD_HUGE 0x80000000
-#endif
-
-/*
* Some number of bits at the level of the page table that points to
* a hugepte are used to encode the size. This masks those bits.
*/
@@ -356,7 +344,11 @@ typedef struct { signed long pd; } hugepd_t;
#ifdef CONFIG_HUGETLB_PAGE
static inline int hugepd_ok(hugepd_t hpd)
{
- return (hpd.pd > 0);
+ /*
+ * hugepd pointer, bottom two bits == 00 and next 4 bits
+ * indicate size of table
+ */
+ return (((hpd.pd & 0x3) == 0x0) && ((hpd.pd & HUGEPD_SHIFT_MASK) != 0));
}
#define is_hugepd(pdep) (hugepd_ok(*((hugepd_t *)(pdep))))
diff --git a/arch/powerpc/include/asm/pgalloc-64.h
b/arch/powerpc/include/asm/pgalloc-64.h
index 292725c..69e352a 100644
--- a/arch/powerpc/include/asm/pgalloc-64.h
+++ b/arch/powerpc/include/asm/pgalloc-64.h
@@ -35,7 +35,10 @@ struct vmemmap_backing {
#define MAX_PGTABLE_INDEX_SIZE 0xf
extern struct kmem_cache *pgtable_cache[];
-#define PGT_CACHE(shift) (pgtable_cache[(shift)-1])
+#define PGT_CACHE(shift) ({ \
+ BUG_ON(!(shift)); \
+ pgtable_cache[(shift) - 1]; \
+ })
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 1a6de0a..9108ce7 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -48,23 +48,6 @@ static u64 gpage_freearray[MAX_NUMBER_GPAGES];
static unsigned nr_gpages;
#endif
-static inline int shift_to_mmu_psize(unsigned int shift)
-{
- int psize;
-
- for (psize = 0; psize < MMU_PAGE_COUNT; ++psize)
- if (mmu_psize_defs[psize].shift == shift)
- return psize;
- return -1;
-}
-
-static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
-{
- if (mmu_psize_defs[mmu_psize].shift)
- return mmu_psize_defs[mmu_psize].shift;
- BUG();
-}
-
#define hugepd_none(hpd) ((hpd).pd == 0)
pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned
*shift)
@@ -145,7 +128,8 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t
*hpdp,
if (unlikely(!hugepd_none(*hpdp)))
break;
else
- hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
+ hpdp->pd = (unsigned long)new |
+ (shift_to_mmu_psize(pshift) << 2);
}
/* If we bailed from the for loop early, an error occurred, clean up */
if (i < num_hugepd) {
@@ -157,7 +141,8 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t
*hpdp,
if (!hugepd_none(*hpdp))
kmem_cache_free(cachep, new);
else
- hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift;
+ hpdp->pd = (unsigned long)new |
+ (shift_to_mmu_psize(pshift) << 2);
#endif
spin_unlock(&mm->page_table_lock);
return 0;
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 7e2246f..a56de85 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -129,8 +129,7 @@ void pgtable_cache_add(unsigned shift, void (*ctor)(void *))
align = max_t(unsigned long, align, minalign);
name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
new = kmem_cache_create(name, table_size, align, 0, ctor);
- PGT_CACHE(shift) = new;
-
+ pgtable_cache[shift - 1] = new;
pr_debug("Allocated pgtable cache for order %d\n", shift);
}
--
1.7.10
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