From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v1 13/19] powerpc/nohash: Refactor checking of no-change in pte_update()
Date: Mon, 11 Sep 2023 21:03:19 +0200 [thread overview]
Message-ID: <47323ad1daf0bc390ed2ce4f08b303bab672bd3c.1694443576.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1694443576.git.christophe.leroy@csgroup.eu>
On nohash/64, a few callers of pte_update() check if there is
really a change in order to avoid an unnecessary write.
Refactor that inside pte_update().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/nohash/64/pgtable.h | 9 ---------
arch/powerpc/include/asm/nohash/pgtable.h | 3 +++
2 files changed, 3 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index b149a39f2685..cba08a62c52c 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -181,8 +181,6 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
{
unsigned long old;
- if (!pte_young(*ptep))
- return 0;
old = pte_update(mm, addr, ptep, _PAGE_ACCESSED, 0, 0);
return (old & _PAGE_ACCESSED) != 0;
}
@@ -198,10 +196,6 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
-
- if ((pte_val(*ptep) & _PAGE_RW) == 0)
- return;
-
pte_update(mm, addr, ptep, _PAGE_RW, 0, 0);
}
@@ -209,9 +203,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
- if ((pte_val(*ptep) & _PAGE_RW) == 0)
- return;
-
pte_update(mm, addr, ptep, _PAGE_RW, 0, 1);
}
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index bd5c3a4baabd..8adaacbbdd1d 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -47,6 +47,9 @@ static inline pte_basic_t pte_update(struct mm_struct *mm, unsigned long addr, p
pte_basic_t old = pte_val(*p);
pte_basic_t new = (old & ~(pte_basic_t)clr) | set;
+ if (new == old)
+ return old;
+
*p = __pte(new);
if (IS_ENABLED(CONFIG_44x) && (old & _PAGE_USER) && (old & _PAGE_EXEC))
--
2.41.0
next prev parent reply other threads:[~2023-09-11 19:12 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-11 19:03 [PATCH v1 00/19] cleanup/refactor pgtable.h Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 01/19] powerpc/8xx: Fix pte_access_permitted() for PAGE_NONE Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 02/19] powerpc/64e: Fix wrong test in __ptep_test_and_clear_young() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 03/19] powerpc/40x: Remove stale PTE_ATOMIC_UPDATES macro Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 04/19] powerpc: Remove pte_ERROR() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 05/19] powerpc: Deduplicate prototypes of ptep_set_access_flags() and phys_mem_access_prot() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 06/19] powerpc: Refactor update_mmu_cache_range() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 07/19] powerpc: Untangle fixmap.h and pgtable.h and mmu.h Christophe Leroy
2023-09-13 11:14 ` kernel test robot
2023-09-11 19:03 ` [PATCH v1 08/19] powerpc/nohash: Remove {pte/pmd}_protnone() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 09/19] powerpc/nohash: Refactor declaration of {map/unmap}_kernel_page() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 10/19] powerpc/nohash: Move 8xx version of pte_update() into pte-8xx.h Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 11/19] powerpc/nohash: Replace #ifdef CONFIG_44x by IS_ENABLED(CONFIG_44x) in pgtable.h Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 12/19] powerpc/nohash: Refactor pte_update() Christophe Leroy
2023-09-11 19:03 ` Christophe Leroy [this message]
2023-09-11 19:03 ` [PATCH v1 14/19] powerpc/nohash: Deduplicate _PAGE_CHG_MASK Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 15/19] powerpc/nohash: Deduplicate pte helpers Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 16/19] powerpc/nohash: Refactor ptep_test_and_clear_young() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 17/19] powerpc/nohash: Deduplicate ptep_set_wrprotect() and ptep_get_and_clear() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 18/19] powerpc/nohash: Refactor pte_clear() Christophe Leroy
2023-09-11 19:03 ` [PATCH v1 19/19] powerpc/nohash: Refactor __ptep_set_access_flags() Christophe Leroy
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