2023-07-13 12:05:18

by Miaohe Lin

[permalink] [raw]
Subject: [PATCH] mm: remove some useless comments of node_stat_item

Some comments of node_stat_item are not that helpful and even confusing,
so remove them. No functional change intended.

Signed-off-by: Miaohe Lin <[email protected]>
---
include/linux/mmzone.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4106fbc5b4b3..844ed29cc260 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -154,10 +154,10 @@ enum zone_stat_item {
enum node_stat_item {
NR_LRU_BASE,
NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
- NR_ACTIVE_ANON, /* " " " " " */
- NR_INACTIVE_FILE, /* " " " " " */
- NR_ACTIVE_FILE, /* " " " " " */
- NR_UNEVICTABLE, /* " " " " " */
+ NR_ACTIVE_ANON,
+ NR_INACTIVE_FILE,
+ NR_ACTIVE_FILE,
+ NR_UNEVICTABLE,
NR_SLAB_RECLAIMABLE_B,
NR_SLAB_UNRECLAIMABLE_B,
NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
--
2.33.0



2023-07-13 12:39:57

by Miaohe Lin

[permalink] [raw]
Subject: Re: [PATCH] mm: remove some useless comments of node_stat_item

On 2023/7/13 20:10, Matthew Wilcox wrote:
> On Thu, Jul 13, 2023 at 07:49:15PM +0800, Miaohe Lin wrote:
>> Some comments of node_stat_item are not that helpful and even confusing,
>> so remove them. No functional change intended.
>
> No, that's very useful and important. Why does it confuse you?

Thanks for your quick respond.

I just can't figure out what these comments want to tell. Could you help explain these?

Thanks.


2023-07-13 12:46:02

by Matthew Wilcox

[permalink] [raw]
Subject: Re: [PATCH] mm: remove some useless comments of node_stat_item

On Thu, Jul 13, 2023 at 07:49:15PM +0800, Miaohe Lin wrote:
> Some comments of node_stat_item are not that helpful and even confusing,
> so remove them. No functional change intended.

No, that's very useful and important. Why does it confuse you?

> enum node_stat_item {
> NR_LRU_BASE,
> NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
> - NR_ACTIVE_ANON, /* " " " " " */
> - NR_INACTIVE_FILE, /* " " " " " */
> - NR_ACTIVE_FILE, /* " " " " " */
> - NR_UNEVICTABLE, /* " " " " " */
> + NR_ACTIVE_ANON,
> + NR_INACTIVE_FILE,
> + NR_ACTIVE_FILE,
> + NR_UNEVICTABLE,
> NR_SLAB_RECLAIMABLE_B,
> NR_SLAB_UNRECLAIMABLE_B,
> NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
> --
> 2.33.0
>
>

2023-07-13 12:59:47

by Matthew Wilcox

[permalink] [raw]
Subject: Re: [PATCH] mm: remove some useless comments of node_stat_item

On Thu, Jul 13, 2023 at 08:18:29PM +0800, Miaohe Lin wrote:
> On 2023/7/13 20:10, Matthew Wilcox wrote:
> > On Thu, Jul 13, 2023 at 07:49:15PM +0800, Miaohe Lin wrote:
> >> Some comments of node_stat_item are not that helpful and even confusing,
> >> so remove them. No functional change intended.
> >
> > No, that's very useful and important. Why does it confuse you?
>
> Thanks for your quick respond.
>
> I just can't figure out what these comments want to tell. Could you help explain these?

Don't snip the thing you want explained to you!

NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
- NR_ACTIVE_ANON, /* " " " " " */
- NR_INACTIVE_FILE, /* " " " " " */
- NR_ACTIVE_FILE, /* " " " " " */
- NR_UNEVICTABLE, /* " " " " " */
+ NR_ACTIVE_ANON,
+ NR_INACTIVE_FILE,
+ NR_ACTIVE_FILE,
+ NR_UNEVICTABLE,

What this is communicating to me is that these five items
(NR_INACTIVE_ANON to NR_UNEVICTABLE) must stay in the same order with
LRU_INACTIVE and LRU_ACTIVE. By removing the ditto-marks from the
subsequent four lines, you've made the comment say that this one line
must stay in the same order as LRU_INACTIVE and LRU_ACTIVE ... which
makes no sense at all.

2023-07-14 01:57:56

by Miaohe Lin

[permalink] [raw]
Subject: Re: [PATCH] mm: remove some useless comments of node_stat_item

On 2023/7/13 20:31, Matthew Wilcox wrote:
> On Thu, Jul 13, 2023 at 08:18:29PM +0800, Miaohe Lin wrote:
>> On 2023/7/13 20:10, Matthew Wilcox wrote:
>>> On Thu, Jul 13, 2023 at 07:49:15PM +0800, Miaohe Lin wrote:
>>>> Some comments of node_stat_item are not that helpful and even confusing,
>>>> so remove them. No functional change intended.
>>>
>>> No, that's very useful and important. Why does it confuse you?
>>
>> Thanks for your quick respond.
>>
>> I just can't figure out what these comments want to tell. Could you help explain these?
>
> Don't snip the thing you want explained to you!
>
> NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
> - NR_ACTIVE_ANON, /* " " " " " */
> - NR_INACTIVE_FILE, /* " " " " " */
> - NR_ACTIVE_FILE, /* " " " " " */
> - NR_UNEVICTABLE, /* " " " " " */
> + NR_ACTIVE_ANON,
> + NR_INACTIVE_FILE,
> + NR_ACTIVE_FILE,
> + NR_UNEVICTABLE,
>
> What this is communicating to me is that these five items
> (NR_INACTIVE_ANON to NR_UNEVICTABLE) must stay in the same order with
> LRU_INACTIVE and LRU_ACTIVE. By removing the ditto-marks from the
> subsequent four lines, you've made the comment say that this one line
> must stay in the same order as LRU_INACTIVE and LRU_ACTIVE ... which
> makes no sense at all.

I see. Many thanks for your kind explanation. :)



2023-07-14 02:51:37

by Anshuman Khandual

[permalink] [raw]
Subject: Re: [PATCH] mm: remove some useless comments of node_stat_item



On 7/13/23 18:01, Matthew Wilcox wrote:
> On Thu, Jul 13, 2023 at 08:18:29PM +0800, Miaohe Lin wrote:
>> On 2023/7/13 20:10, Matthew Wilcox wrote:
>>> On Thu, Jul 13, 2023 at 07:49:15PM +0800, Miaohe Lin wrote:
>>>> Some comments of node_stat_item are not that helpful and even confusing,
>>>> so remove them. No functional change intended.
>>>
>>> No, that's very useful and important. Why does it confuse you?
>>
>> Thanks for your quick respond.
>>
>> I just can't figure out what these comments want to tell. Could you help explain these?
>
> Don't snip the thing you want explained to you!
>
> NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
> - NR_ACTIVE_ANON, /* " " " " " */
> - NR_INACTIVE_FILE, /* " " " " " */
> - NR_ACTIVE_FILE, /* " " " " " */
> - NR_UNEVICTABLE, /* " " " " " */
> + NR_ACTIVE_ANON,
> + NR_INACTIVE_FILE,
> + NR_ACTIVE_FILE,
> + NR_UNEVICTABLE,
>
> What this is communicating to me is that these five items
> (NR_INACTIVE_ANON to NR_UNEVICTABLE) must stay in the same order with
> LRU_INACTIVE and LRU_ACTIVE. By removing the ditto-marks from the
> subsequent four lines, you've made the comment say that this one line
> must stay in the same order as LRU_INACTIVE and LRU_ACTIVE ... which
> makes no sense at all.

Just wondering - would it be better to repeat these comments in words for
each line than use "ditto-marks" ?