powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault

upatepp can get called for a nohpte fault when we find from the linux
page table that the translation was hashed before. In that case
we are sure that there is no existing translation, hence we could
avoid doing tlbie.

We could possibly race with a parallel fault filling the TLB. But
that should be ok because updatepp is only ever relaxing permissions.
We also look at linux pte permission bits when filling hash pte
permission bits. We also hold the linux pte busy bits while
inserting/updating a hashpte entry, hence a paralle update of
linux pte is not possible. On the other hand mprotect involves
ptep_modify_prot_start which cause a hpte invalidate and not updatepp.

Performance number:
We use randbox_access_bench written by Anton.

Kernel with THP disabled and smaller hash page table size.

    86.60%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_updatepp
     2.10%  random_access_b  random_access_bench              [.] doit
     1.99%  random_access_b  [kernel.kallsyms]                [k] .do_raw_spin_lock
     1.85%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_insert
     1.26%  random_access_b  [kernel.kallsyms]                [k] .native_flush_hash_range
     1.18%  random_access_b  [kernel.kallsyms]                [k] .__delay
     0.69%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_remove
     0.37%  random_access_b  [kernel.kallsyms]                [k] .clear_user_page
     0.34%  random_access_b  [kernel.kallsyms]                [k] .__hash_page_64K
     0.32%  random_access_b  [kernel.kallsyms]                [k] fast_exception_return
     0.30%  random_access_b  [kernel.kallsyms]                [k] .hash_page_mm

With Fix:

    27.54%  random_access_b  random_access_bench              [.] doit
    22.90%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_insert
     5.76%  random_access_b  [kernel.kallsyms]                [k] .native_hpte_remove
     5.20%  random_access_b  [kernel.kallsyms]                [k] fast_exception_return
     5.12%  random_access_b  [kernel.kallsyms]                [k] .__hash_page_64K
     4.80%  random_access_b  [kernel.kallsyms]                [k] .hash_page_mm
     3.31%  random_access_b  [kernel.kallsyms]                [k] data_access_common
     1.84%  random_access_b  [kernel.kallsyms]                [k] .trace_hardirqs_on_caller

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

5 files changed, 8 insertions, 7 deletions

diff --git a/arch/powerpc/platforms/cell/beat_htab.c b/arch/powerpc/platforms/cell/beat_htab.c
index d4d245c0d787..bee9232fe619 100644
--- a/arch/powerpc/platforms/cell/beat_htab.c
+++ b/arch/powerpc/platforms/cell/beat_htab.c
@@ -186,7 +186,7 @@ static long beat_lpar_hpte_updatepp(unsigned long slot,
 				    unsigned long newpp,
 				    unsigned long vpn,
 				    int psize, int apsize,
-				    int ssize, int local)
+				    int ssize, unsigned long flags)
 {
 	unsigned long lpar_rc;
 	u64 dummy0, dummy1;
@@ -369,7 +369,7 @@ static long beat_lpar_hpte_updatepp_v3(unsigned long slot,
 				       unsigned long newpp,
 				       unsigned long vpn,
 				       int psize, int apsize,
-				       int ssize, int local)
+				       int ssize, unsigned long flags)
 {
 	unsigned long lpar_rc;
 	unsigned long want_v;
diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c
index ffcbd242e669..f7af74f83693 100644
--- a/arch/powerpc/platforms/cell/spu_base.c
+++ b/arch/powerpc/platforms/cell/spu_base.c
@@ -181,7 +181,8 @@ static int __spu_trap_data_seg(struct spu *spu, unsigned long ea)
 	return 0;
 }
 
-extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap); //XXX
+extern int hash_page(unsigned long ea, unsigned long access,
+		     unsigned long trap, unsigned long dsisr); //XXX
 static int __spu_trap_data_map(struct spu *spu, unsigned long ea, u64 dsisr)
 {
 	int ret;
@@ -196,7 +197,7 @@ static int __spu_trap_data_map(struct spu *spu, unsigned long ea, u64 dsisr)
 	    (REGION_ID(ea) != USER_REGION_ID)) {
 
 		spin_unlock(&spu->register_lock);
-		ret = hash_page(ea, _PAGE_PRESENT, 0x300);
+		ret = hash_page(ea, _PAGE_PRESENT, 0x300, dsisr);
 		spin_lock(&spu->register_lock);
 
 		if (!ret) {
diff --git a/arch/powerpc/platforms/cell/spufs/fault.c b/arch/powerpc/platforms/cell/spufs/fault.c
index e45894a08118..d98f845ac777 100644
--- a/arch/powerpc/platforms/cell/spufs/fault.c
+++ b/arch/powerpc/platforms/cell/spufs/fault.c
@@ -144,7 +144,7 @@ int spufs_handle_class1(struct spu_context *ctx)
 	access = (_PAGE_PRESENT | _PAGE_USER);
 	access |= (dsisr & MFC_DSISR_ACCESS_PUT) ? _PAGE_RW : 0UL;
 	local_irq_save(flags);
-	ret = hash_page(ea, access, 0x300);
+	ret = hash_page(ea, access, 0x300, dsisr);
 	local_irq_restore(flags);
 
 	/* hashing failed, so try the actual fault handler */
diff --git a/arch/powerpc/platforms/ps3/htab.c b/arch/powerpc/platforms/ps3/htab.c
index 3e270e3412ae..2f95d33cf34a 100644
--- a/arch/powerpc/platforms/ps3/htab.c
+++ b/arch/powerpc/platforms/ps3/htab.c
@@ -110,7 +110,7 @@ static long ps3_hpte_remove(unsigned long hpte_group)
 
 static long ps3_hpte_updatepp(unsigned long slot, unsigned long newpp,
 			      unsigned long vpn, int psize, int apsize,
-			      int ssize, int local)
+			      int ssize, unsigned long inv_flags)
 {
 	int result;
 	u64 hpte_v, want_v, hpte_rs;
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 832f221840f2..469751d92004 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -284,7 +284,7 @@ static long pSeries_lpar_hpte_updatepp(unsigned long slot,
 				       unsigned long newpp,
 				       unsigned long vpn,
 				       int psize, int apsize,
-				       int ssize, int local)
+				       int ssize, unsigned long inv_flags)
 {
 	unsigned long lpar_rc;
 	unsigned long flags = (newpp & 7) | H_AVPN;