2020-02-01 08:06:54

by Christophe Leroy

Subject: [PATCH v2] powerpc/32s: Don't flush all TLBs when flushing one page

When flushing any memory range, the flushing function
flushes all TLBs.

When (start) and (end - 1) are in the same memory page,
flush that page instead.

Signed-off-by: Christophe Leroy <[email protected]>
---
v2: Reworked the test as the previous one was always false (end - start was PAGE_SIZE - 1 for a single page)
---
arch/powerpc/mm/book3s32/tlb.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/mm/book3s32/tlb.c b/arch/powerpc/mm/book3s32/tlb.c
index 2fcd321040ff..724c0490fb17 100644
--- a/arch/powerpc/mm/book3s32/tlb.c
+++ b/arch/powerpc/mm/book3s32/tlb.c
@@ -79,11 +79,14 @@ static void flush_range(struct mm_struct *mm, unsigned long start,
int count;
unsigned int ctx = mm->context.id;

+ start &= PAGE_MASK;
if (!Hash) {
- _tlbia();
+ if (end - start <= PAGE_SIZE)
+ _tlbie(start);
+ else
+ _tlbia();
return;
}
- start &= PAGE_MASK;
if (start >= end)
return;
end = (end - 1) | ~PAGE_MASK;
--
2.25.0

2020-02-01 16:28:45

by Christophe Leroy

Subject: Re: [PATCH v2] powerpc/32s: Don't flush all TLBs when flushing one page

Le 01/02/2020 à 09:04, Christophe Leroy a écrit :
> When flushing any memory range, the flushing function
> flushes all TLBs.
>
> When (start) and (end - 1) are in the same memory page,
> flush that page instead.
>
> Signed-off-by: Christophe Leroy <[email protected]>

Reviewed-by: Segher Boessenkool <[email protected]>

> ---
> v2: Reworked the test as the previous one was always false (end - start was PAGE_SIZE - 1 for a single page)
> ---
> arch/powerpc/mm/book3s32/tlb.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/mm/book3s32/tlb.c b/arch/powerpc/mm/book3s32/tlb.c
> index 2fcd321040ff..724c0490fb17 100644
> --- a/arch/powerpc/mm/book3s32/tlb.c
> +++ b/arch/powerpc/mm/book3s32/tlb.c
> @@ -79,11 +79,14 @@ static void flush_range(struct mm_struct *mm, unsigned long start,
> int count;
> unsigned int ctx = mm->context.id;
>
> + start &= PAGE_MASK;
> if (!Hash) {
> - _tlbia();
> + if (end - start <= PAGE_SIZE)
> + _tlbie(start);
> + else
> + _tlbia();
> return;
> }
> - start &= PAGE_MASK;
> if (start >= end)
> return;
> end = (end - 1) | ~PAGE_MASK;
>

2020-03-06 00:29:05

by Michael Ellerman

Subject: Re: [PATCH v2] powerpc/32s: Don't flush all TLBs when flushing one page

On Sat, 2020-02-01 at 08:04:31 UTC, Christophe Leroy wrote:
> When flushing any memory range, the flushing function
> flushes all TLBs.
>
> When (start) and (end - 1) are in the same memory page,
> flush that page instead.
>
> Signed-off-by: Christophe Leroy <[email protected]>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/030e347430957f6f7f29db9099368f8b86c0bf76

cheers