* [PATCH] doc: mm: migration doesn't use FOLL_SPLIT anymore
@ 2019-04-18 20:17 Yang Shi
2019-04-18 20:30 ` Zi Yan
2019-04-19 18:48 ` Jonathan Corbet
0 siblings, 2 replies; 3+ messages in thread
From: Yang Shi @ 2019-04-18 20:17 UTC (permalink / raw)
To: mhocko, kirill.shutemov, ziy, rppt, corbet, akpm
Cc: yang.shi, linux-doc, linux-mm, linux-kernel
When demonstrating FOLL_SPLIT in transhuge document, migration is used
as an example. But, since commit 94723aafb9e7 ("mm: unclutter THP
migration"), the way of THP migration is totally changed. FOLL_SPLIT is
not used by migration anymore due to the change.
Remove the obsolete example to avoid confusion.
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
Documentation/vm/transhuge.rst | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/Documentation/vm/transhuge.rst b/Documentation/vm/transhuge.rst
index a8cf680..8df3806 100644
--- a/Documentation/vm/transhuge.rst
+++ b/Documentation/vm/transhuge.rst
@@ -55,13 +55,7 @@ prevent page from being split by anyone.
In case you can't handle compound pages if they're returned by
follow_page, the FOLL_SPLIT bit can be specified as parameter to
follow_page, so that it will split the hugepages before returning
-them. Migration for example passes FOLL_SPLIT as parameter to
-follow_page because it's not hugepage aware and in fact it can't work
-at all on hugetlbfs (but it instead works fine on transparent
-hugepages thanks to FOLL_SPLIT). migration simply can't deal with
-hugepages being returned (as it's not only checking the pfn of the
-page and pinning it during the copy but it pretends to migrate the
-memory in regular page sizes and with regular pte/pmd mappings).
+them.
Graceful fallback
=================
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] doc: mm: migration doesn't use FOLL_SPLIT anymore
2019-04-18 20:17 [PATCH] doc: mm: migration doesn't use FOLL_SPLIT anymore Yang Shi
@ 2019-04-18 20:30 ` Zi Yan
2019-04-19 18:48 ` Jonathan Corbet
1 sibling, 0 replies; 3+ messages in thread
From: Zi Yan @ 2019-04-18 20:30 UTC (permalink / raw)
To: Yang Shi
Cc: mhocko, kirill.shutemov, rppt, corbet, akpm, linux-doc, linux-mm,
linux-kernel
On 18 Apr 2019, at 16:17, Yang Shi wrote:
> When demonstrating FOLL_SPLIT in transhuge document, migration is used
> as an example. But, since commit 94723aafb9e7 ("mm: unclutter THP
> migration"), the way of THP migration is totally changed. FOLL_SPLIT
> is
> not used by migration anymore due to the change.
>
> Remove the obsolete example to avoid confusion.
>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
> ---
> Documentation/vm/transhuge.rst | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/Documentation/vm/transhuge.rst
> b/Documentation/vm/transhuge.rst
> index a8cf680..8df3806 100644
> --- a/Documentation/vm/transhuge.rst
> +++ b/Documentation/vm/transhuge.rst
> @@ -55,13 +55,7 @@ prevent page from being split by anyone.
> In case you can't handle compound pages if they're returned by
> follow_page, the FOLL_SPLIT bit can be specified as parameter to
> follow_page, so that it will split the hugepages before returning
> -them. Migration for example passes FOLL_SPLIT as parameter to
> -follow_page because it's not hugepage aware and in fact it can't work
> -at all on hugetlbfs (but it instead works fine on transparent
> -hugepages thanks to FOLL_SPLIT). migration simply can't deal with
> -hugepages being returned (as it's not only checking the pfn of the
> -page and pinning it during the copy but it pretends to migrate the
> -memory in regular page sizes and with regular pte/pmd mappings).
> +them.
>
> Graceful fallback
> =================
> --
> 1.8.3.1
Thanks for updating the document.
Reviewed-by: Zi Yan <ziy@nvidia.com>
--
Best Regards,
Yan Zi
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] doc: mm: migration doesn't use FOLL_SPLIT anymore
2019-04-18 20:17 [PATCH] doc: mm: migration doesn't use FOLL_SPLIT anymore Yang Shi
2019-04-18 20:30 ` Zi Yan
@ 2019-04-19 18:48 ` Jonathan Corbet
1 sibling, 0 replies; 3+ messages in thread
From: Jonathan Corbet @ 2019-04-19 18:48 UTC (permalink / raw)
To: Yang Shi
Cc: mhocko, kirill.shutemov, ziy, rppt, akpm, linux-doc, linux-mm,
linux-kernel
On Fri, 19 Apr 2019 04:17:04 +0800
Yang Shi <yang.shi@linux.alibaba.com> wrote:
> When demonstrating FOLL_SPLIT in transhuge document, migration is used
> as an example. But, since commit 94723aafb9e7 ("mm: unclutter THP
> migration"), the way of THP migration is totally changed. FOLL_SPLIT is
> not used by migration anymore due to the change.
>
> Remove the obsolete example to avoid confusion.
>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Applied, thanks.
jon
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-04-18 20:30 ` Zi Yan
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