From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH v2 4/7] powerpc/64s/radix: make ptep_get_and_clear_full non-atomic for the full case
Date: Sun, 20 May 2018 10:43:44 +1000 [thread overview]
Message-ID: <20180520004347.19508-5-npiggin@gmail.com> (raw)
In-Reply-To: <20180520004347.19508-1-npiggin@gmail.com>
This matches other architectures, when we know there will be no
further accesses to the address (e.g., for teardown), page table
entries can be cleared non-atomically.
The comments about NMMU are bogus: all MMU notifiers (including NMMU)
are released at this point, with their TLBs flushed. An NMMU access at
this point would be a bug.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/include/asm/book3s/64/radix.h | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 705193e7192f..fcd92f9b6ec0 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -176,14 +176,8 @@ static inline pte_t radix__ptep_get_and_clear_full(struct mm_struct *mm,
unsigned long old_pte;
if (full) {
- /*
- * If we are trying to clear the pte, we can skip
- * the DD1 pte update sequence and batch the tlb flush. The
- * tlb flush batching is done by mmu gather code. We
- * still keep the cmp_xchg update to make sure we get
- * correct R/C bit which might be updated via Nest MMU.
- */
- old_pte = __radix_pte_update(ptep, ~0ul, 0);
+ old_pte = pte_val(*ptep);
+ *ptep = __pte(0);
} else
old_pte = radix__pte_update(mm, addr, ptep, ~0ul, 0, 0);
--
2.17.0
next prev parent reply other threads:[~2018-05-20 0:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-20 0:43 [PATCH v2 0/7] Various TLB and PTE improvements Nicholas Piggin
2018-05-20 0:43 ` [PATCH v2 1/7] powerpc/64s/radix: do not flush TLB on spurious fault Nicholas Piggin
2018-05-21 6:06 ` Aneesh Kumar K.V
2018-05-24 10:37 ` Nicholas Piggin
2018-05-20 0:43 ` [PATCH v2 2/7] powerpc/64s/radix: reset mm_cpumask for single thread process when possible Nicholas Piggin
2018-05-20 0:43 ` [PATCH v2 3/7] powerpc/64s/radix: make single threaded mms always flush all translations from non-local CPUs Nicholas Piggin
2018-05-20 0:43 ` Nicholas Piggin [this message]
2018-05-20 0:43 ` [PATCH v2 5/7] powerpc/64s/radix: optimise pte_update Nicholas Piggin
2018-05-20 0:43 ` [PATCH v2 6/7] powerpc/64s/radix: prefetch user address in update_mmu_cache Nicholas Piggin
2018-05-20 0:43 ` [PATCH v2 7/7] powerpc/64s/radix: avoid ptesync after set_pte and ptep_set_access_flags Nicholas Piggin
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