[PATCH v2 13/37] powerpc/nohash: Refactor checking of no-change in pte_update()
From: Christophe Leroy <hidden>
Date: 2023-09-25 18:32:40
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <redacted> --- 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