From: Bibo Mao <maobibo@loongson.cn>
To: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Paul Burton <paulburton@kernel.org>,
Mike Rapoport <rppt@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Daniel Silsby <dansilsby@gmail.com>
Cc: linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] MIPS: Do not flush tlb when setting pmd entry
Date: Thu, 18 Jun 2020 18:56:55 +0800 [thread overview]
Message-ID: <1592477815-836-1-git-send-email-maobibo@loongson.cn> (raw)
Function set_pmd_at is to set pmd entry, if tlb entry need to
be flushed, there exists pmdp_huge_clear_flush alike function
before set_pmd_at is called. So it is not necessary to call
flush_tlb_all in this function.
In these scenarios, tlb for the pmd range needs to be flushed:
1. privilege degrade such as wrprotect is set on the pmd entry
2. pmd entry is cleared
3. there is exception if set_pmd_at is issued by dup_mmap, since
flush_tlb_mm is called for parent process, it is not necessary
to flush tlb in function copy_huge_pmd.
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
v2:
- add the same operation on mips32 system
- update changelog description
---
arch/mips/mm/pgtable-32.c | 1 -
arch/mips/mm/pgtable-64.c | 1 -
2 files changed, 2 deletions(-)
diff --git a/arch/mips/mm/pgtable-32.c b/arch/mips/mm/pgtable-32.c
index bd4b065..61891af 100644
--- a/arch/mips/mm/pgtable-32.c
+++ b/arch/mips/mm/pgtable-32.c
@@ -45,7 +45,6 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t pmd)
{
*pmdp = pmd;
- flush_tlb_all();
}
#endif /* defined(CONFIG_TRANSPARENT_HUGEPAGE) */
diff --git a/arch/mips/mm/pgtable-64.c b/arch/mips/mm/pgtable-64.c
index 183ff9f..7536f78 100644
--- a/arch/mips/mm/pgtable-64.c
+++ b/arch/mips/mm/pgtable-64.c
@@ -100,7 +100,6 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t pmd)
{
*pmdp = pmd;
- flush_tlb_all();
}
void __init pagetable_init(void)
--
1.8.3.1
reply other threads:[~2020-06-18 10:57 UTC|newest]
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