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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
To: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au
Cc: linuxppc-dev@lists.ozlabs.org,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: [PATCH 2/8] powerpc/mm: add _PAGE_HASHPTE similar to 4K hash
Date: Tue,  1 Mar 2016 12:59:18 +0530	[thread overview]
Message-ID: <1456817364-3329-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> (raw)
In-Reply-To: <1456817364-3329-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>

We don't need to update linux page table entry with _PAGE_HASHPTE early
in hash pte fault. A parallel pte update will loop via _PAGE_BUSY
and look at _PAGE_HASHPTE for a required hpte flush only if
_PAGE_BUSY is cleared. That ensures a pte update will wait for a
parallel hpte insert to finish before looking at _PAGE_HASHPTE bit.

To avoid further confusion drop setting _PAGE_HASHPTE in cmpxchg in __hash_page_4K.

commit 41743a4e34f0 ("powerpc: Free a PTE bit on ppc64 with 64K pages")
did similar change for 64K config

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/mm/hash64_4k.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/hash64_4k.c b/arch/powerpc/mm/hash64_4k.c
index e3e76b929f33..47d1b26effc6 100644
--- a/arch/powerpc/mm/hash64_4k.c
+++ b/arch/powerpc/mm/hash64_4k.c
@@ -44,7 +44,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
 		 * a write access. Since this is 4K insert of 64K page size
 		 * also add _PAGE_COMBO
 		 */
-		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED | _PAGE_HASHPTE;
+		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
 		if (access & _PAGE_RW)
 			new_pte |= _PAGE_DIRTY;
 	} while (old_pte != __cmpxchg_u64((unsigned long *)ptep,
-- 
2.5.0

  parent reply	other threads:[~2016-03-01  7:29 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-01  7:29 [PATCH 0/8] BOOk3s 64 MMU code cleanup Aneesh Kumar K.V
2016-03-01  7:29 ` [PATCH 1/8] powerp/mm: Update code comments Aneesh Kumar K.V
2016-03-04  0:40   ` [1/8] " Michael Ellerman
2016-03-01  7:29 ` Aneesh Kumar K.V [this message]
2016-03-04  0:40   ` [2/8] powerpc/mm: add _PAGE_HASHPTE similar to 4K hash Michael Ellerman
2016-03-01  7:29 ` [PATCH 3/8] powerpc/mm: Use flush_tlb_page in ptep_clear_flush_young Aneesh Kumar K.V
2016-03-01  7:29 ` [PATCH 4/8] powerpc/mm: Move hash related mmu-*.h headers to book3s/ Aneesh Kumar K.V
2016-03-04  0:40   ` [4/8] " Michael Ellerman
2016-03-01  7:29 ` [PATCH 5/8] powerpc/mm: Create a new headers for tlbflush for hash64 Aneesh Kumar K.V
2016-03-04  0:40   ` [5/8] " Michael Ellerman
2016-03-01  7:29 ` [PATCH 6/8] powerpc/mm: Move hash page table related functions to pgtable-hash64.c Aneesh Kumar K.V
2016-03-03  2:33   ` [PATCH V2] " Aneesh Kumar K.V
2016-03-01  7:29 ` [PATCH 7/8] powerpc/mm: THP is only available on hash64 as of now Aneesh Kumar K.V
2016-03-01  7:29 ` [PATCH 8/8] powerpc/mm: Use generic version of pmdp_clear_flush_young Aneesh Kumar K.V

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