| Message ID | 20220624025309.1033400-3-ying.huang@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/7] migrate: fix syscall move_pages() return value for failure | expand |
On 6/24/2022 10:53 AM, Huang Ying wrote: > Before commit b5bade978e9b ("mm: migrate: fix the return value of > migrate_pages()"), the tail pages of THP will be put in the "from" > list directly. So one of the loop cursors (page2) needs to be reset, > as is done in try_split_thp() via list_safe_reset_next(). But after > the commit, the tail pages of THP will be put in a dedicated > list (thp_split_pages). That is, the "from" list will not be changed > during splitting. So, it's unnecessary to call list_safe_reset_next() > anymore. > > This is a code cleanup, no functionality changes are expected. > > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > Cc: Baolin Wang <baolin.wang@linux.alibaba.com> > Cc: Zi Yan <ziy@nvidia.com> > Cc: Yang Shi <shy828301@gmail.com> > --- Looks good to me. Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> > mm/migrate.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index a271554be7a1..82444e7df9f1 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1300,16 +1300,13 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, > return rc; > } > > -static inline int try_split_thp(struct page *page, struct page **page2, > - struct list_head *from) > +static inline int try_split_thp(struct page *page, struct list_head *split_pages) > { > - int rc = 0; > + int rc; > > lock_page(page); > - rc = split_huge_page_to_list(page, from); > + rc = split_huge_page_to_list(page, split_pages); > unlock_page(page); > - if (!rc) > - list_safe_reset_next(page, *page2, lru); > > return rc; > } > @@ -1413,7 +1410,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > /* THP migration is unsupported */ > if (is_thp) { > nr_thp_failed++; > - if (!try_split_thp(page, &page2, &thp_split_pages)) { > + if (!try_split_thp(page, &thp_split_pages)) { > nr_thp_split++; > goto retry; > } > @@ -1432,7 +1429,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, > */ > if (is_thp && !nosplit) { > nr_thp_failed++; > - if (!try_split_thp(page, &page2, &thp_split_pages)) { > + if (!try_split_thp(page, &thp_split_pages)) { > nr_thp_split++; > goto retry; > }
diff --git a/mm/migrate.c b/mm/migrate.c index a271554be7a1..82444e7df9f1 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1300,16 +1300,13 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, return rc; } -static inline int try_split_thp(struct page *page, struct page **page2, - struct list_head *from) +static inline int try_split_thp(struct page *page, struct list_head *split_pages) { - int rc = 0; + int rc; lock_page(page); - rc = split_huge_page_to_list(page, from); + rc = split_huge_page_to_list(page, split_pages); unlock_page(page); - if (!rc) - list_safe_reset_next(page, *page2, lru); return rc; } @@ -1413,7 +1410,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, /* THP migration is unsupported */ if (is_thp) { nr_thp_failed++; - if (!try_split_thp(page, &page2, &thp_split_pages)) { + if (!try_split_thp(page, &thp_split_pages)) { nr_thp_split++; goto retry; } @@ -1432,7 +1429,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, */ if (is_thp && !nosplit) { nr_thp_failed++; - if (!try_split_thp(page, &page2, &thp_split_pages)) { + if (!try_split_thp(page, &thp_split_pages)) { nr_thp_split++; goto retry; }
Before commit b5bade978e9b ("mm: migrate: fix the return value of migrate_pages()"), the tail pages of THP will be put in the "from" list directly. So one of the loop cursors (page2) needs to be reset, as is done in try_split_thp() via list_safe_reset_next(). But after the commit, the tail pages of THP will be put in a dedicated list (thp_split_pages). That is, the "from" list will not be changed during splitting. So, it's unnecessary to call list_safe_reset_next() anymore. This is a code cleanup, no functionality changes are expected. Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Yang Shi <shy828301@gmail.com> --- mm/migrate.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)