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* [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru()
@ 2020-08-27 23:42 Yu Zhao
  2020-08-27 23:42 ` [PATCH 2/2] mm: use self-explanatory macros rather than "2" Yu Zhao
  2020-08-29 18:12 ` [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru() Yu Zhao
  0 siblings, 2 replies; 6+ messages in thread
From: Yu Zhao @ 2020-08-27 23:42 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-mm, linux-kernel, Yu Zhao

This is a trivial but worth having clean-up patch. There should be
no side effects except page->lru is temporarily poisoned after it's
deleted but before it's added to the new list in move_pages_to_lru()
(which is not a problem).

Signed-off-by: Yu Zhao <yuzhao@google.com>
---
 mm/swap.c   |  4 +---
 mm/vmscan.c | 14 ++++----------
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 40bf20a75278..2735ecf0f566 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -597,11 +597,9 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
 {
 	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
 	    !PageSwapCache(page) && !PageUnevictable(page)) {
-		bool active = PageActive(page);
 		int nr_pages = thp_nr_pages(page);
 
-		del_page_from_lru_list(page, lruvec,
-				       LRU_INACTIVE_ANON + active);
+		del_page_from_lru_list(page, lruvec, page_lru(page));
 		ClearPageActive(page);
 		ClearPageReferenced(page);
 		/*
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 99e1796eb833..b479ced26cd3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1845,13 +1845,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 	int nr_pages, nr_moved = 0;
 	LIST_HEAD(pages_to_free);
 	struct page *page;
-	enum lru_list lru;
 
 	while (!list_empty(list)) {
 		page = lru_to_page(list);
 		VM_BUG_ON_PAGE(PageLRU(page), page);
+		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
-			list_del(&page->lru);
 			spin_unlock_irq(&pgdat->lru_lock);
 			putback_lru_page(page);
 			spin_lock_irq(&pgdat->lru_lock);
@@ -1860,16 +1859,10 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 		lruvec = mem_cgroup_page_lruvec(page, pgdat);
 
 		SetPageLRU(page);
-		lru = page_lru(page);
-
-		nr_pages = thp_nr_pages(page);
-		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
-		list_move(&page->lru, &lruvec->lists[lru]);
+		add_page_to_lru_list(page, lruvec, page_lru(page));
 
 		if (put_page_testzero(page)) {
-			__ClearPageLRU(page);
-			__ClearPageActive(page);
-			del_page_from_lru_list(page, lruvec, lru);
+			del_page_from_lru_list(page, lruvec, page_off_lru(page));
 
 			if (unlikely(PageCompound(page))) {
 				spin_unlock_irq(&pgdat->lru_lock);
@@ -1878,6 +1871,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
 			} else
 				list_add(&page->lru, &pages_to_free);
 		} else {
+			nr_pages = thp_nr_pages(page);
 			nr_moved += nr_pages;
 			if (PageActive(page))
 				workingset_age_nonresident(lruvec, nr_pages);
-- 
2.28.0.402.g5ffc5be6b7-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 2/2] mm: use self-explanatory macros rather than "2"
  2020-08-27 23:42 [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru() Yu Zhao
@ 2020-08-27 23:42 ` Yu Zhao
  2020-08-29 18:12 ` [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru() Yu Zhao
  1 sibling, 0 replies; 6+ messages in thread
From: Yu Zhao @ 2020-08-27 23:42 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-mm, linux-kernel, Yu Zhao

This is a trivial clean-up patch. Take it or leave it.

Signed-off-by: Yu Zhao <yuzhao@google.com>
---
 include/linux/mmzone.h | 12 ++++++++----
 include/linux/vmstat.h |  2 +-
 mm/vmscan.c            |  2 +-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 8379432f4f2f..be1cdbf8317f 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -266,6 +266,8 @@ static inline bool is_active_lru(enum lru_list lru)
 	return (lru == LRU_ACTIVE_ANON || lru == LRU_ACTIVE_FILE);
 }
 
+#define ANON_AND_FILE 2
+
 enum lruvec_flags {
 	LRUVEC_CONGESTED,		/* lruvec has many dirty pages
 					 * backed by a congested BDI
@@ -283,8 +285,8 @@ struct lruvec {
 	unsigned long			file_cost;
 	/* Non-resident age, driven by LRU movement */
 	atomic_long_t			nonresident_age;
-	/* Refaults at the time of last reclaim cycle, anon=0, file=1 */
-	unsigned long			refaults[2];
+	/* Refaults at the time of last reclaim cycle */
+	unsigned long			refaults[ANON_AND_FILE];
 	/* Various lruvec state flags (enum lruvec_flags) */
 	unsigned long			flags;
 #ifdef CONFIG_MEMCG
@@ -406,6 +408,8 @@ enum zone_type {
 
 #ifndef __GENERATING_BOUNDS_H
 
+#define ASYNC_AND_SYNC 2
+
 struct zone {
 	/* Read-mostly fields */
 
@@ -525,8 +529,8 @@ struct zone {
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 	/* pfn where compaction free scanner should start */
 	unsigned long		compact_cached_free_pfn;
-	/* pfn where async and sync compaction migration scanner should start */
-	unsigned long		compact_cached_migrate_pfn[2];
+	/* pfn where compaction migration scanner should start */
+	unsigned long		compact_cached_migrate_pfn[ASYNC_AND_SYNC];
 	unsigned long		compact_init_migrate_pfn;
 	unsigned long		compact_init_free_pfn;
 #endif
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 91220ace31da..d5431c1bf6e5 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -28,7 +28,7 @@ struct reclaim_stat {
 	unsigned nr_writeback;
 	unsigned nr_immediate;
 	unsigned nr_pageout;
-	unsigned nr_activate[2];
+	unsigned nr_activate[ANON_AND_FILE];
 	unsigned nr_ref_keep;
 	unsigned nr_unmap_fail;
 	unsigned nr_lazyfree_fail;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b479ced26cd3..c4ddb2a88b07 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2231,7 +2231,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 	struct mem_cgroup *memcg = lruvec_memcg(lruvec);
 	unsigned long anon_cost, file_cost, total_cost;
 	int swappiness = mem_cgroup_swappiness(memcg);
-	u64 fraction[2];
+	u64 fraction[ANON_AND_FILE];
 	u64 denominator = 0;	/* gcc */
 	enum scan_balance scan_balance;
 	unsigned long ap, fp;
-- 
2.28.0.402.g5ffc5be6b7-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru()
  2020-08-27 23:42 [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru() Yu Zhao
  2020-08-27 23:42 ` [PATCH 2/2] mm: use self-explanatory macros rather than "2" Yu Zhao
@ 2020-08-29 18:12 ` Yu Zhao
  2020-08-30  8:31   ` Alex Shi
  1 sibling, 1 reply; 6+ messages in thread
From: Yu Zhao @ 2020-08-29 18:12 UTC (permalink / raw)
  To: Alex Shi; +Cc: linux-mm, linux-kernel, Andrew Morton

On Thu, Aug 27, 2020 at 05:42:01PM -0600, Yu Zhao wrote:
> This is a trivial but worth having clean-up patch. There should be
> no side effects except page->lru is temporarily poisoned after it's
> deleted but before it's added to the new list in move_pages_to_lru()
> (which is not a problem).
> 
> Signed-off-by: Yu Zhao <yuzhao@google.com>

Hi Alex, I just realized your
  [v18,08/32] mm/vmscan: remove unnecessary lruvec adding
at
  https://patchwork.kernel.org/patch/11733123/
also touches move_pages_to_lru(). I agree it's better not to add
a page we are going to free to the list in the first place. The
rest in this patch would be too trivial to be a separate one (on
top of yours).

So would you mind taking of the clean-up too in your series? I'll
drop this one then. Thanks.

> ---
>  mm/swap.c   |  4 +---
>  mm/vmscan.c | 14 ++++----------
>  2 files changed, 5 insertions(+), 13 deletions(-)
> 
> diff --git a/mm/swap.c b/mm/swap.c
> index 40bf20a75278..2735ecf0f566 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -597,11 +597,9 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
>  {
>  	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
>  	    !PageSwapCache(page) && !PageUnevictable(page)) {
> -		bool active = PageActive(page);
>  		int nr_pages = thp_nr_pages(page);
>  
> -		del_page_from_lru_list(page, lruvec,
> -				       LRU_INACTIVE_ANON + active);
> +		del_page_from_lru_list(page, lruvec, page_lru(page));
>  		ClearPageActive(page);
>  		ClearPageReferenced(page);
>  		/*
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 99e1796eb833..b479ced26cd3 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1845,13 +1845,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>  	int nr_pages, nr_moved = 0;
>  	LIST_HEAD(pages_to_free);
>  	struct page *page;
> -	enum lru_list lru;
>  
>  	while (!list_empty(list)) {
>  		page = lru_to_page(list);
>  		VM_BUG_ON_PAGE(PageLRU(page), page);
> +		list_del(&page->lru);
>  		if (unlikely(!page_evictable(page))) {
> -			list_del(&page->lru);
>  			spin_unlock_irq(&pgdat->lru_lock);
>  			putback_lru_page(page);
>  			spin_lock_irq(&pgdat->lru_lock);
> @@ -1860,16 +1859,10 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>  		lruvec = mem_cgroup_page_lruvec(page, pgdat);
>  
>  		SetPageLRU(page);
> -		lru = page_lru(page);
> -
> -		nr_pages = thp_nr_pages(page);
> -		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
> -		list_move(&page->lru, &lruvec->lists[lru]);
> +		add_page_to_lru_list(page, lruvec, page_lru(page));
>  
>  		if (put_page_testzero(page)) {
> -			__ClearPageLRU(page);
> -			__ClearPageActive(page);
> -			del_page_from_lru_list(page, lruvec, lru);
> +			del_page_from_lru_list(page, lruvec, page_off_lru(page));
>  
>  			if (unlikely(PageCompound(page))) {
>  				spin_unlock_irq(&pgdat->lru_lock);
> @@ -1878,6 +1871,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>  			} else
>  				list_add(&page->lru, &pages_to_free);
>  		} else {
> +			nr_pages = thp_nr_pages(page);
>  			nr_moved += nr_pages;
>  			if (PageActive(page))
>  				workingset_age_nonresident(lruvec, nr_pages);
> -- 
> 2.28.0.402.g5ffc5be6b7-goog
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru()
  2020-08-29 18:12 ` [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru() Yu Zhao
@ 2020-08-30  8:31   ` Alex Shi
  2020-08-30 23:44     ` Yu Zhao
  0 siblings, 1 reply; 6+ messages in thread
From: Alex Shi @ 2020-08-30  8:31 UTC (permalink / raw)
  To: Yu Zhao; +Cc: linux-mm, linux-kernel, Andrew Morton



在 2020/8/30 上午2:12, Yu Zhao 写道:
> On Thu, Aug 27, 2020 at 05:42:01PM -0600, Yu Zhao wrote:
>> This is a trivial but worth having clean-up patch. There should be
>> no side effects except page->lru is temporarily poisoned after it's
>> deleted but before it's added to the new list in move_pages_to_lru()
>> (which is not a problem).
>>
>> Signed-off-by: Yu Zhao <yuzhao@google.com>
> 
> Hi Alex, I just realized your
>   [v18,08/32] mm/vmscan: remove unnecessary lruvec adding
> at
>   https://patchwork.kernel.org/patch/11733123/
> also touches move_pages_to_lru(). I agree it's better not to add
> a page we are going to free to the list in the first place. The
> rest in this patch would be too trivial to be a separate one (on
> top of yours).
> 
> So would you mind taking of the clean-up too in your series? I'll
> drop this one then. Thanks.
> 
>> ---
>>  mm/swap.c   |  4 +---
>>  mm/vmscan.c | 14 ++++----------
>>  2 files changed, 5 insertions(+), 13 deletions(-)
>>
>> diff --git a/mm/swap.c b/mm/swap.c
>> index 40bf20a75278..2735ecf0f566 100644
>> --- a/mm/swap.c
>> +++ b/mm/swap.c
>> @@ -597,11 +597,9 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
>>  {
>>  	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
>>  	    !PageSwapCache(page) && !PageUnevictable(page)) {
>> -		bool active = PageActive(page);
>>  		int nr_pages = thp_nr_pages(page);
>>  
>> -		del_page_from_lru_list(page, lruvec,
>> -				       LRU_INACTIVE_ANON + active);
>> +		del_page_from_lru_list(page, lruvec, page_lru(page));
>>  		ClearPageActive(page);
>>  		ClearPageReferenced(page);
>>  		/*
>> diff --git a/mm/vmscan.c b/mm/vmscan.c
>> index 99e1796eb833..b479ced26cd3 100644
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -1845,13 +1845,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>>  	int nr_pages, nr_moved = 0;
>>  	LIST_HEAD(pages_to_free);
>>  	struct page *page;
>> -	enum lru_list lru;
>>  
>>  	while (!list_empty(list)) {
>>  		page = lru_to_page(list);
>>  		VM_BUG_ON_PAGE(PageLRU(page), page);
>> +		list_del(&page->lru);
>>  		if (unlikely(!page_evictable(page))) {
>> -			list_del(&page->lru);
>>  			spin_unlock_irq(&pgdat->lru_lock);
>>  			putback_lru_page(page);
>>  			spin_lock_irq(&pgdat->lru_lock);
>> @@ -1860,16 +1859,10 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>>  		lruvec = mem_cgroup_page_lruvec(page, pgdat);
>>  
>>  		SetPageLRU(page);
>> -		lru = page_lru(page);
>> -
>> -		nr_pages = thp_nr_pages(page);
>> -		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
>> -		list_move(&page->lru, &lruvec->lists[lru]);
>> +		add_page_to_lru_list(page, lruvec, page_lru(page));
>>  
>>  		if (put_page_testzero(page)) {
>> -			__ClearPageLRU(page);


it's interesting to know the PageLRU left has no bad impact in real life. 
it justs seems a path confliction with my that patch. 

>> -			__ClearPageActive(page);
>> -			del_page_from_lru_list(page, lruvec, lru);
>> +			del_page_from_lru_list(page, lruvec, page_off_lru(page));
>>  
>>  			if (unlikely(PageCompound(page))) {
>>  				spin_unlock_irq(&pgdat->lru_lock);
>> @@ -1878,6 +1871,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
>>  			} else
>>  				list_add(&page->lru, &pages_to_free);
>>  		} else {
>> +			nr_pages = thp_nr_pages(page);
>>  			nr_moved += nr_pages;
>>  			if (PageActive(page))
>>  				workingset_age_nonresident(lruvec, nr_pages);
>> -- 
>> 2.28.0.402.g5ffc5be6b7-goog
>>

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru()
  2020-08-30  8:31   ` Alex Shi
@ 2020-08-30 23:44     ` Yu Zhao
  2020-08-31 17:41       ` Yu Zhao
  0 siblings, 1 reply; 6+ messages in thread
From: Yu Zhao @ 2020-08-30 23:44 UTC (permalink / raw)
  To: Alex Shi; +Cc: linux-mm, linux-kernel, Andrew Morton

On Sun, Aug 30, 2020 at 04:31:38PM +0800, Alex Shi wrote:
> 
> 
> 在 2020/8/30 上午2:12, Yu Zhao 写道:
> > On Thu, Aug 27, 2020 at 05:42:01PM -0600, Yu Zhao wrote:
> >> This is a trivial but worth having clean-up patch. There should be
> >> no side effects except page->lru is temporarily poisoned after it's
> >> deleted but before it's added to the new list in move_pages_to_lru()
> >> (which is not a problem).
> >>
> >> Signed-off-by: Yu Zhao <yuzhao@google.com>
> > 
> > Hi Alex, I just realized your
> >   [v18,08/32] mm/vmscan: remove unnecessary lruvec adding
> > at
> >   https://patchwork.kernel.org/patch/11733123/
> > also touches move_pages_to_lru(). I agree it's better not to add
> > a page we are going to free to the list in the first place. The
> > rest in this patch would be too trivial to be a separate one (on
> > top of yours).
> > 
> > So would you mind taking of the clean-up too in your series? I'll
> > drop this one then. Thanks.

Ok, maybe I wasn't clear before. Please see what exactly I'm asking
you to consider below.

> >> diff --git a/mm/swap.c b/mm/swap.c
> >> index 40bf20a75278..2735ecf0f566 100644
> >> --- a/mm/swap.c
> >> +++ b/mm/swap.c
> >> @@ -597,11 +597,9 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
> >>  {
> >>  	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
> >>  	    !PageSwapCache(page) && !PageUnevictable(page)) {
> >> -		bool active = PageActive(page);
> >>  		int nr_pages = thp_nr_pages(page);
> >>  
> >> -		del_page_from_lru_list(page, lruvec,
> >> -				       LRU_INACTIVE_ANON + active);
> >> +		del_page_from_lru_list(page, lruvec, page_lru(page));
> >>  		ClearPageActive(page);
> >>  		ClearPageReferenced(page);
> >>  		/*

1) The above has no conflict with your series and therefore can go
separately. Feel free to include it.

> >> diff --git a/mm/vmscan.c b/mm/vmscan.c
> >> index 99e1796eb833..b479ced26cd3 100644
> >> --- a/mm/vmscan.c
> >> +++ b/mm/vmscan.c
> >> @@ -1845,13 +1845,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
> >>  	int nr_pages, nr_moved = 0;
> >>  	LIST_HEAD(pages_to_free);
> >>  	struct page *page;
> >> -	enum lru_list lru;
> >>  
> >>  	while (!list_empty(list)) {
> >>  		page = lru_to_page(list);
> >>  		VM_BUG_ON_PAGE(PageLRU(page), page);
> >> +		list_del(&page->lru);
> >>  		if (unlikely(!page_evictable(page))) {
> >> -			list_del(&page->lru);
> >>  			spin_unlock_irq(&pgdat->lru_lock);
> >>  			putback_lru_page(page);
> >>  			spin_lock_irq(&pgdat->lru_lock);

2) The above is the same change you've made.

> >> @@ -1860,16 +1859,10 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
> >>  		lruvec = mem_cgroup_page_lruvec(page, pgdat);
> >>  
> >>  		SetPageLRU(page);
> >> -		lru = page_lru(page);
> >> -
> >> -		nr_pages = thp_nr_pages(page);
> >> -		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
> >> -		list_move(&page->lru, &lruvec->lists[lru]);
> >> +		add_page_to_lru_list(page, lruvec, page_lru(page));
> >>  
> >>  		if (put_page_testzero(page)) {
> >> -			__ClearPageLRU(page);
> 
> it's interesting to know the PageLRU left has no bad impact in real life. 
> it justs seems a path confliction with my that patch. 

(No, we can't leave PG_lru uncleared. It's done by the page_off_lru()
right below).

> >> -			__ClearPageActive(page);
> >> -			del_page_from_lru_list(page, lruvec, lru);
> >> +			del_page_from_lru_list(page, lruvec, page_off_lru(page));
> >>  
> >>  			if (unlikely(PageCompound(page))) {
> >>  				spin_unlock_irq(&pgdat->lru_lock);
> >> @@ -1878,6 +1871,7 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
> >>  			} else
> >>  				list_add(&page->lru, &pages_to_free);
> >>  		} else {
> >> +			nr_pages = thp_nr_pages(page);
> >>  			nr_moved += nr_pages;
> >>  			if (PageActive(page))
> >>  				workingset_age_nonresident(lruvec, nr_pages);

3) The above is the conflict. Since we won't add and then delete a
page after your patch, we won't need it. But I do want this (you've
snipped from your reply, so I take that you already figured it out):

-		lru = page_lru(page);
-
-		nr_pages = thp_nr_pages(page);
-		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
-		list_move(&page->lru, &lruvec->lists[lru]);
+		add_page_to_lru_list(page, lruvec, page_lru(page));

No worries if you prefer this to go separately too.

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru()
  2020-08-30 23:44     ` Yu Zhao
@ 2020-08-31 17:41       ` Yu Zhao
  0 siblings, 0 replies; 6+ messages in thread
From: Yu Zhao @ 2020-08-31 17:41 UTC (permalink / raw)
  To: Alex Shi; +Cc: linux-mm, linux-kernel, Andrew Morton

On Sun, Aug 30, 2020 at 05:44:04PM -0600, Yu Zhao wrote:
> On Sun, Aug 30, 2020 at 04:31:38PM +0800, Alex Shi wrote:
> > 
> > 
> > 在 2020/8/30 上午2:12, Yu Zhao 写道:
> > > On Thu, Aug 27, 2020 at 05:42:01PM -0600, Yu Zhao wrote:
> > >> This is a trivial but worth having clean-up patch. There should be
> > >> no side effects except page->lru is temporarily poisoned after it's
> > >> deleted but before it's added to the new list in move_pages_to_lru()
> > >> (which is not a problem).
> > >>
> > >> Signed-off-by: Yu Zhao <yuzhao@google.com>
> > > 
> > > Hi Alex, I just realized your
> > >   [v18,08/32] mm/vmscan: remove unnecessary lruvec adding
> > > at
> > >   https://patchwork.kernel.org/patch/11733123/
> > > also touches move_pages_to_lru(). I agree it's better not to add
> > > a page we are going to free to the list in the first place. The
> > > rest in this patch would be too trivial to be a separate one (on
> > > top of yours).
> > > 
> > > So would you mind taking of the clean-up too in your series? I'll
> > > drop this one then. Thanks.
> 
> Ok, maybe I wasn't clear before. Please see what exactly I'm asking
> you to consider below.
> 
> > >> diff --git a/mm/swap.c b/mm/swap.c
> > >> index 40bf20a75278..2735ecf0f566 100644
> > >> --- a/mm/swap.c
> > >> +++ b/mm/swap.c
> > >> @@ -597,11 +597,9 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec,
> > >>  {
> > >>  	if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) &&
> > >>  	    !PageSwapCache(page) && !PageUnevictable(page)) {
> > >> -		bool active = PageActive(page);
> > >>  		int nr_pages = thp_nr_pages(page);
> > >>  
> > >> -		del_page_from_lru_list(page, lruvec,
> > >> -				       LRU_INACTIVE_ANON + active);
> > >> +		del_page_from_lru_list(page, lruvec, page_lru(page));
> > >>  		ClearPageActive(page);
> > >>  		ClearPageReferenced(page);
> > >>  		/*
> 
> 1) The above has no conflict with your series and therefore can go
> separately. Feel free to include it.
> 
> > >> diff --git a/mm/vmscan.c b/mm/vmscan.c
> > >> index 99e1796eb833..b479ced26cd3 100644
> > >> --- a/mm/vmscan.c
> > >> +++ b/mm/vmscan.c
> > >> @@ -1845,13 +1845,12 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
> > >>  	int nr_pages, nr_moved = 0;
> > >>  	LIST_HEAD(pages_to_free);
> > >>  	struct page *page;
> > >> -	enum lru_list lru;
> > >>  
> > >>  	while (!list_empty(list)) {
> > >>  		page = lru_to_page(list);
> > >>  		VM_BUG_ON_PAGE(PageLRU(page), page);
> > >> +		list_del(&page->lru);
> > >>  		if (unlikely(!page_evictable(page))) {
> > >> -			list_del(&page->lru);
> > >>  			spin_unlock_irq(&pgdat->lru_lock);
> > >>  			putback_lru_page(page);
> > >>  			spin_lock_irq(&pgdat->lru_lock);
> 
> 2) The above is the same change you've made.
> 
> > >> @@ -1860,16 +1859,10 @@ static unsigned noinline_for_stack move_pages_to_lru(struct lruvec *lruvec,
> > >>  		lruvec = mem_cgroup_page_lruvec(page, pgdat);
> > >>  
> > >>  		SetPageLRU(page);
> > >> -		lru = page_lru(page);
> > >> -
> > >> -		nr_pages = thp_nr_pages(page);
> > >> -		update_lru_size(lruvec, lru, page_zonenum(page), nr_pages);
> > >> -		list_move(&page->lru, &lruvec->lists[lru]);
> > >> +		add_page_to_lru_list(page, lruvec, page_lru(page));
> > >>  
> > >>  		if (put_page_testzero(page)) {
> > >> -			__ClearPageLRU(page);
> > 
> > it's interesting to know the PageLRU left has no bad impact in real life. 
> > it justs seems a path confliction with my that patch. 
> 
> (No, we can't leave PG_lru uncleared. It's done by the page_off_lru()
> right below).

Sorry about this false claim. You are right: we need to keep
__ClearPageLRU() here. page_off_lru() doesn't do it for us.

I'll fix this in v2. Thanks.

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2020-08-31 17:42 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-27 23:42 [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru() Yu Zhao
2020-08-27 23:42 ` [PATCH 2/2] mm: use self-explanatory macros rather than "2" Yu Zhao
2020-08-29 18:12 ` [PATCH 1/2] mm: use add_page_to_lru_list()/page_lru()/page_off_lru() Yu Zhao
2020-08-30  8:31   ` Alex Shi
2020-08-30 23:44     ` Yu Zhao
2020-08-31 17:41       ` Yu Zhao

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