2022-11-30 09:32:16

by ye.xingchen

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Subject: [PATCH] mm/huge_memory: add TRANSPARENT_HUGEPAGE_NEVER for THP

From: ye xingchen <[email protected]>

Sometimes we may need the /sys/kernel/mm/transparent_hugepage/enabled to
default as [never] at the first time.

Signed-off-by: ye xingchen <[email protected]>
---
mm/Kconfig | 5 +++++
mm/huge_memory.c | 2 ++
2 files changed, 7 insertions(+)

diff --git a/mm/Kconfig b/mm/Kconfig
index ff7b209dec05..ded8c1da6267 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -797,6 +797,11 @@ choice
madvise(MADV_HUGEPAGE) but it won't risk to increase the
memory footprint of applications without a guaranteed
benefit.
+
+ config TRANSPARENT_HUGEPAGE_NEVER
+ bool "never"
+ help
+ Disabling Transparent Hugepage.
endchoice

config THP_SWAP
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c0c57828110d..3571417aa70a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -60,6 +60,8 @@ unsigned long transparent_hugepage_flags __read_mostly =
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE
(1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)|
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE_NEVER
#endif
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG)|
(1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG)|
--
2.25.1


2022-12-01 21:12:44

by Matthew Wilcox

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Subject: Re: [PATCH] mm/huge_memory: add TRANSPARENT_HUGEPAGE_NEVER for THP

On Wed, Nov 30, 2022 at 04:51:46PM +0800, [email protected] wrote:
> From: ye xingchen <[email protected]>
>
> Sometimes we may need the /sys/kernel/mm/transparent_hugepage/enabled to
> default as [never] at the first time.

What is going wrong with THP enabled that you need to disable it?

2022-12-02 18:20:55

by David Rientjes

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Subject: Re: [PATCH] mm/huge_memory: add TRANSPARENT_HUGEPAGE_NEVER for THP

On Thu, 1 Dec 2022, Matthew Wilcox wrote:

> On Wed, Nov 30, 2022 at 04:51:46PM +0800, [email protected] wrote:
> > From: ye xingchen <[email protected]>
> >
> > Sometimes we may need the /sys/kernel/mm/transparent_hugepage/enabled to
> > default as [never] at the first time.
>
> What is going wrong with THP enabled that you need to disable it?
>

That would be useful to know in addition to why this needs to be part of
.config and not simply using the kernel command line option.

2022-12-02 20:59:39

by Hugh Dickins

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Subject: Re: [PATCH] mm/huge_memory: add TRANSPARENT_HUGEPAGE_NEVER for THP

On Fri, 2 Dec 2022, David Rientjes wrote:
> On Thu, 1 Dec 2022, Matthew Wilcox wrote:
> > On Wed, Nov 30, 2022 at 04:51:46PM +0800, [email protected] wrote:
> > > From: ye xingchen <[email protected]>
> > >
> > > Sometimes we may need the /sys/kernel/mm/transparent_hugepage/enabled to
> > > default as [never] at the first time.
> >
> > What is going wrong with THP enabled that you need to disable it?
> >
>
> That would be useful to know in addition to why this needs to be part of
> .config and not simply using the kernel command line option.

There is also the puzzle of what new feature gets added by

#ifdef CONFIG_TRANSPARENT_HUGEPAGE_NEVER
#endif

Hugh