[PATCH] docs/vm: remove unused 3 items explanation for /proc/vmstat

[PATCH] docs/vm: remove unused 3 items explanation for /proc/vmstat

[Alex Shi]

Commit 5647bc293ab1 ("mm: compaction: Move migration fail/success
stats to migrate.c"), removed 3 items in /proc/vmstat. but the docs
still has their explanation. let's remove them.

"compact_blocks_moved",
"compact_pages_moved",
"compact_pagemigrate_failed",

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net> 
Cc: Andrew Morton <akpm@linux-foundation.org> 
Cc: Yang Shi <yang.shi@linux.alibaba.com> 
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> 
Cc: David Rientjes <rientjes@google.com> 
Cc: Zi Yan <ziy@nvidia.com> 
Cc: linux-doc@vger.kernel.org 
Cc: linux-kernel@vger.kernel.org 
---
 Documentation/admin-guide/mm/transhuge.rst | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
index b2acd0d395ca..3b8a336511a4 100644
--- a/Documentation/admin-guide/mm/transhuge.rst
+++ b/Documentation/admin-guide/mm/transhuge.rst
@@ -401,21 +401,6 @@ compact_fail
 	is incremented if the system tries to compact memory
 	but failed.
 
-compact_pages_moved
-	is incremented each time a page is moved. If
-	this value is increasing rapidly, it implies that the system
-	is copying a lot of data to satisfy the huge page allocation.
-	It is possible that the cost of copying exceeds any savings
-	from reduced TLB misses.
-
-compact_pagemigrate_failed
-	is incremented when the underlying mechanism
-	for moving a page failed.
-
-compact_blocks_moved
-	is incremented each time memory compaction examines
-	a huge page aligned range of pages.
-
 It is possible to establish how long the stalls were using the function
 tracer to record how long was spent in __alloc_pages_nodemask and
 using the mm_page_alloc tracepoint to identify which allocations were
-- 
2.29.GIT

Re: [PATCH] docs/vm: remove unused 3 items explanation for /proc/vmstat

[Zi Yan]

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On 16 Nov 2020, at 4:51, Alex Shi wrote:

> Commit 5647bc293ab1 ("mm: compaction: Move migration fail/success
> stats to migrate.c"), removed 3 items in /proc/vmstat. but the docs
> still has their explanation. let's remove them.
>
> "compact_blocks_moved",
> "compact_pages_moved",
> "compact_pagemigrate_failed",
>
> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Yang Shi <yang.shi@linux.alibaba.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: linux-doc@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  Documentation/admin-guide/mm/transhuge.rst | 15 ---------------
>  1 file changed, 15 deletions(-)
>

LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com>.

—
Best Regards,
Yan Zi

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Re: [PATCH] docs/vm: remove unused 3 items explanation for /proc/vmstat

[Jonathan Corbet]

On Mon, 16 Nov 2020 17:51:22 +0800
Alex Shi <alex.shi@linux.alibaba.com> wrote:

> Commit 5647bc293ab1 ("mm: compaction: Move migration fail/success
> stats to migrate.c"), removed 3 items in /proc/vmstat. but the docs
> still has their explanation. let's remove them.
> 
> "compact_blocks_moved",
> "compact_pages_moved",
> "compact_pagemigrate_failed",

So a quick look says that the above-mentioned patch didn't remove those
three items; two of them were, instead, renamed.  Rather than just taking
out the old information, it seems we should actually update it to reflect
current reality?

Thanks,

jon

Re: [PATCH] docs/vm: remove unused 3 items explanation for /proc/vmstat

[Alex Shi]

在 2020/11/19 上午4:46, Jonathan Corbet 写道:
> On Mon, 16 Nov 2020 17:51:22 +0800
> Alex Shi <alex.shi@linux.alibaba.com> wrote:
> 
>> Commit 5647bc293ab1 ("mm: compaction: Move migration fail/success
>> stats to migrate.c"), removed 3 items in /proc/vmstat. but the docs
>> still has their explanation. let's remove them.
>>
>> "compact_blocks_moved",
>> "compact_pages_moved",
>> "compact_pagemigrate_failed",
> 
> So a quick look says that the above-mentioned patch didn't remove those
> three items; two of them were, instead, renamed.  Rather than just taking
> out the old information, it seems we should actually update it to reflect
> current reality?
> 

I thought about the replacement, but there are couple of migration events
have no explanation:

#ifdef CONFIG_MIGRATION
        "pgmigrate_success",
        "pgmigrate_fail",
        "thp_migration_success",
        "thp_migration_fail",
        "thp_migration_split",
#endif

It's better to fill them together, also change current explanation accordinglly.
but I'm not so confident on this now...

Thanks
Alex