linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Jaewon Kim <jaewon31.kim@samsung.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: minchan@kernel.org, mgorman@suse.de, m.szyprowski@samsung.com,
	mina86@mina86.com, shli@fb.com, akpm@linux-foundation.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	jaewon31.kim@gmail.com, ytk.lee@samsung.com
Subject: Re: [PATCH v2] mm/vmscan: count layzfree pages and fix nr_isolated_* mismatch
Date: Thu, 23 Apr 2020 12:16:02 +0900	[thread overview]
Message-ID: <5EA10872.3010500@samsung.com> (raw)
In-Reply-To: <20200422130751.GD358439@cmpxchg.org>



On 2020년 04월 22일 22:07, Johannes Weiner wrote:
> On Wed, Apr 22, 2020 at 05:48:15PM +0900, Jaewon Kim wrote:
>> @@ -1295,11 +1295,15 @@ static unsigned long shrink_page_list(struct list_head *page_list,
>>  		 */
>>  		if (page_mapped(page)) {
>>  			enum ttu_flags flags = ttu_flags | TTU_BATCH_FLUSH;
>> +			bool lazyfree = PageAnon(page) && !PageSwapBacked(page);
>>  
>>  			if (unlikely(PageTransHuge(page)))
>>  				flags |= TTU_SPLIT_HUGE_PMD;
>> +
>>  			if (!try_to_unmap(page, flags)) {
>>  				stat->nr_unmap_fail += nr_pages;
>> +				if (lazyfree && PageSwapBacked(page))
> This looks pretty strange, until you remember that try_to_unmap()
> could SetPageSwapbacked again.
>
> This might be more obvious?
>
> 			was_swapbacked = PageSwapBacked(page);
> 			if (!try_to_unmap(page, flags)) {
> 				stat->nr_unmap_fail += nr_pages;
> 				if (!was_swapbacked && PageSwapBacked(page))
Hello Johannes, thank you for your comment.

The name can changed from layzyfree to was_swapbacked.
By the way, did you mean removing PageAnon(page), too? It seems to be OK, though.
>> +					stat->nr_lazyfree_fail += nr_pages;
>>  				goto activate_locked;
> Or at least was_lazyfree.
Sorry but I'm confused.
I think you meant additional comment to previous your comment
rather than you wanted to rename stat->nr_lazyfree_fail to stat->was_lazyfree.
>
>> @@ -1491,8 +1495,8 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
>>  		.priority = DEF_PRIORITY,
>>  		.may_unmap = 1,
>>  	};
>> -	struct reclaim_stat dummy_stat;
>> -	unsigned long ret;
>> +	struct reclaim_stat stat;
>> +	unsigned long reclaimed;
> nr_reclaimed would be better.
I will add nr_ prefix on next patch.
>
> I also prefer keeping dummy_stat, since that's still what it is.
This patch uses stat.nr_lazyfree_fail, I do not understand why it is still dummy_stat.
If you want, I will keep dummy_stat, though.

Thank you
Jaewon Kim
>
>



  reply	other threads:[~2020-04-23  3:16 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200422084832epcas1p333225f9b6a00c9ce36f5f5d63fe6e3bf@epcas1p3.samsung.com>
2020-04-22  8:48 ` Jaewon Kim
2020-04-22 13:07   ` Johannes Weiner
2020-04-23  3:16     ` Jaewon Kim [this message]
2020-04-23 16:05       ` Johannes Weiner
2020-04-23 20:00         ` Minchan Kim
2020-04-24  4:16           ` Jaewon Kim
2020-04-24 13:17             ` Johannes Weiner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=5EA10872.3010500@samsung.com \
    --to=jaewon31.kim@samsung.com \
    --cc=akpm@linux-foundation.org \
    --cc=hannes@cmpxchg.org \
    --cc=jaewon31.kim@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=m.szyprowski@samsung.com \
    --cc=mgorman@suse.de \
    --cc=mina86@mina86.com \
    --cc=minchan@kernel.org \
    --cc=shli@fb.com \
    --cc=ytk.lee@samsung.com \
    --subject='Re: [PATCH v2] mm/vmscan: count layzfree pages and fix nr_isolated_* mismatch' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).