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 <[email protected]>
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
>
?? 2020/8/30 ????2:12, Yu Zhao д??:
> 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 <[email protected]>
>
> 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
>>
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 <[email protected]>
> >
> > 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.
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 <[email protected]>
> > >
> > > 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.