| Message ID | 20210427133214.2270207-3-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Cleanup and fixup for huge_memory | expand |
On Tue, Apr 27, 2021 at 6:32 AM Miaohe Lin <linmiaohe@huawei.com> wrote: > > Now that we can represent the location of ->deferred_list instead of > ->mapping + ->index, make use of it to improve readability. Reviewed-by: Yang Shi <shy828301@gmail.com> > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/huge_memory.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 63ed6b25deaa..76ca1eb2a223 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2868,7 +2868,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, > spin_lock_irqsave(&ds_queue->split_queue_lock, flags); > /* Take pin on all head pages to avoid freeing them under us */ > list_for_each_safe(pos, next, &ds_queue->split_queue) { > - page = list_entry((void *)pos, struct page, mapping); > + page = list_entry((void *)pos, struct page, deferred_list); > page = compound_head(page); > if (get_page_unless_zero(page)) { > list_move(page_deferred_list(page), &list); > @@ -2883,7 +2883,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, > spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); > > list_for_each_safe(pos, next, &list) { > - page = list_entry((void *)pos, struct page, mapping); > + page = list_entry((void *)pos, struct page, deferred_list); > if (!trylock_page(page)) > goto next; > /* split_huge_page() removes page from list on success */ > -- > 2.23.0 > >
On 4/27/21 7:02 PM, Miaohe Lin wrote: > Now that we can represent the location of ->deferred_list instead of > ->mapping + ->index, make use of it to improve readability. Could you please explain how page->deferred_list and page->mapping are interchangeable here ? > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/huge_memory.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 63ed6b25deaa..76ca1eb2a223 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2868,7 +2868,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, > spin_lock_irqsave(&ds_queue->split_queue_lock, flags); > /* Take pin on all head pages to avoid freeing them under us */ > list_for_each_safe(pos, next, &ds_queue->split_queue) { > - page = list_entry((void *)pos, struct page, mapping); > + page = list_entry((void *)pos, struct page, deferred_list); > page = compound_head(page); > if (get_page_unless_zero(page)) { > list_move(page_deferred_list(page), &list); > @@ -2883,7 +2883,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, > spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); > > list_for_each_safe(pos, next, &list) { > - page = list_entry((void *)pos, struct page, mapping); > + page = list_entry((void *)pos, struct page, deferred_list); > if (!trylock_page(page)) > goto next; > /* split_huge_page() removes page from list on success */ >
On 2021/4/28 11:07, Anshuman Khandual wrote: > > On 4/27/21 7:02 PM, Miaohe Lin wrote: >> Now that we can represent the location of ->deferred_list instead of >> ->mapping + ->index, make use of it to improve readability. > > Could you please explain how page->deferred_list and page->mapping > are interchangeable here ? It's because there is a union in struct page: union { struct { struct list_head lru; struct address_space *mapping; pgoff_t index; unsigned long private; }; struct { unsigned long _compound_pad_1; atomic_t hpage_pinned_refcount; struct list_head *deferred_list*; }; }; And initially there is no deferred_list and it's added via commit 66a6ffd2af42 ("mm: combine first three unions in struct page"). Also commit fa3015b7eed5 ("mm: use page->deferred_list") did the similar cleanup. Am I expected to add these to the commit log? Many thanks. > >> >> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> >> --- >> mm/huge_memory.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> index 63ed6b25deaa..76ca1eb2a223 100644 >> --- a/mm/huge_memory.c >> +++ b/mm/huge_memory.c >> @@ -2868,7 +2868,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, >> spin_lock_irqsave(&ds_queue->split_queue_lock, flags); >> /* Take pin on all head pages to avoid freeing them under us */ >> list_for_each_safe(pos, next, &ds_queue->split_queue) { >> - page = list_entry((void *)pos, struct page, mapping); >> + page = list_entry((void *)pos, struct page, deferred_list); >> page = compound_head(page); >> if (get_page_unless_zero(page)) { >> list_move(page_deferred_list(page), &list); >> @@ -2883,7 +2883,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, >> spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); >> >> list_for_each_safe(pos, next, &list) { >> - page = list_entry((void *)pos, struct page, mapping); >> + page = list_entry((void *)pos, struct page, deferred_list); >> if (!trylock_page(page)) >> goto next; >> /* split_huge_page() removes page from list on success */ >> > . >
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 63ed6b25deaa..76ca1eb2a223 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2868,7 +2868,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, spin_lock_irqsave(&ds_queue->split_queue_lock, flags); /* Take pin on all head pages to avoid freeing them under us */ list_for_each_safe(pos, next, &ds_queue->split_queue) { - page = list_entry((void *)pos, struct page, mapping); + page = list_entry((void *)pos, struct page, deferred_list); page = compound_head(page); if (get_page_unless_zero(page)) { list_move(page_deferred_list(page), &list); @@ -2883,7 +2883,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); list_for_each_safe(pos, next, &list) { - page = list_entry((void *)pos, struct page, mapping); + page = list_entry((void *)pos, struct page, deferred_list); if (!trylock_page(page)) goto next; /* split_huge_page() removes page from list on success */
Now that we can represent the location of ->deferred_list instead of ->mapping + ->index, make use of it to improve readability. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> --- mm/huge_memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)