powerpc/mm: Use H_READ with H_READ_4

This will bulk read 4 hash pte slot entries and should reduce the loop

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

2 files changed, 44 insertions, 27 deletions

diff --git a/arch/powerpc/include/asm/plpar_wrappers.h b/arch/powerpc/include/asm/plpar_wrappers.h
index 67859edbf8fd..1b394247afc2 100644
--- a/arch/powerpc/include/asm/plpar_wrappers.h
+++ b/arch/powerpc/include/asm/plpar_wrappers.h
@@ -202,6 +202,23 @@ static inline long plpar_pte_read_raw(unsigned long flags, unsigned long ptex,
 }
 
 /*
+ * ptes must be 8*sizeof(unsigned long)
+ */
+static inline long plpar_pte_read_4(unsigned long flags, unsigned long ptex,
+                                    unsigned long *ptes)
+
+{
+        long rc;
+        unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
+
+        rc = plpar_hcall9(H_READ, retbuf, flags | H_READ_4, ptex);
+
+        memcpy(ptes, retbuf, 8*sizeof(unsigned long));
+
+        return rc;
+}
+
+/*
  * plpar_pte_read_4_raw can be called in real mode.
  * ptes must be 8*sizeof(unsigned long)
  */
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 6d46547871aa..477290ad855e 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -315,48 +315,48 @@ static long pSeries_lpar_hpte_updatepp(unsigned long slot,
         return 0;
 }
 
-static unsigned long pSeries_lpar_hpte_getword0(unsigned long slot)
+static long __pSeries_lpar_hpte_find(unsigned long want_v, unsigned long hpte_group)
 {
-        unsigned long dword0;
-        unsigned long lpar_rc;
-        unsigned long dummy_word1;
-        unsigned long flags;
+        long lpar_rc;
+        unsigned long i, j;
+        struct {
+                unsigned long pteh;
+                unsigned long ptel;
+        } ptes[4];
 
-        /* Read 1 pte at a time                        */
-        /* Do not need RPN to logical page translation */
-        /* No cross CEC PFT access                     */
-        flags = 0;
+        for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
 
-        lpar_rc = plpar_pte_read(flags, slot, &dword0, &dummy_word1);
+                lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);
+                if (lpar_rc != H_SUCCESS)
+                        continue;
 
-        BUG_ON(lpar_rc != H_SUCCESS);
+                for (j = 0; j < 4; j++) {
+                        if (HPTE_V_COMPARE(ptes[j].pteh, want_v) &&
+                            (ptes[j].pteh & HPTE_V_VALID))
+                                return i + j;
+                }
+        }
 
-        return dword0;
+        return -1;
 }
 
 static long pSeries_lpar_hpte_find(unsigned long vpn, int psize, int ssize)
 {
-        unsigned long hash;
-        unsigned long i;
         long slot;
-        unsigned long want_v, hpte_v;
+        unsigned long hash;
+        unsigned long want_v;
+        unsigned long hpte_group;
 
         hash = hpt_hash(vpn, mmu_psize_defs[psize].shift, ssize);
         want_v = hpte_encode_avpn(vpn, psize, ssize);
 
         /* Bolted entries are always in the primary group */
-        slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
-        for (i = 0; i < HPTES_PER_GROUP; i++) {
-                hpte_v = pSeries_lpar_hpte_getword0(slot);
-
-                if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID))
-                        /* HPTE matches */
-                        return slot;
-                ++slot;
-        }
-
-        return -1;
-} 
+        hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
+        slot = __pSeries_lpar_hpte_find(want_v, hpte_group);
+        if (slot < 0)
+                return -1;
+        return hpte_group + slot;
+}
 
 static void pSeries_lpar_hpte_updateboltedpp(unsigned long newpp,
                                              unsigned long ea,