| Message ID | 20220419122234.45083-1-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/mempolicy: clean up the code logic in queue_pages_pte_range | expand |
On Tue, Apr 19, 2022 at 5:22 AM Miaohe Lin <linmiaohe@huawei.com> wrote: > > Since commit e5947d23edd8 ("mm: mempolicy: don't have to split pmd for > huge zero page"), THP is never splited in queue_pages_pmd. Thus 2 is > never returned now. We can remove such unnecessary ret != 2 check and > clean up the relevant comment. Minor improvements in readability. Nice catch. Yeah, it was missed when I worked on that commit. Reviewed-by: Yang Shi <shy828301@gmail.com> > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > --- > mm/mempolicy.c | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index 75a8b247f631..3934476fb708 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -441,12 +441,11 @@ static inline bool queue_pages_required(struct page *page, > } > > /* > - * queue_pages_pmd() has four possible return values: > + * queue_pages_pmd() has three possible return values: > * 0 - pages are placed on the right node or queued successfully, or > * special page is met, i.e. huge zero page. > * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were > * specified. > - * 2 - THP was split. > * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an > * existing page was already on a node that does not follow the > * policy. > @@ -508,18 +507,13 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr, > struct page *page; > struct queue_pages *qp = walk->private; > unsigned long flags = qp->flags; > - int ret; > bool has_unmovable = false; > pte_t *pte, *mapped_pte; > spinlock_t *ptl; > > ptl = pmd_trans_huge_lock(pmd, vma); > - if (ptl) { > - ret = queue_pages_pmd(pmd, ptl, addr, end, walk); > - if (ret != 2) > - return ret; > - } > - /* THP was split, fall through to pte walk */ > + if (ptl) > + return queue_pages_pmd(pmd, ptl, addr, end, walk); > > if (pmd_trans_unstable(pmd)) > return 0; > -- > 2.23.0 > >
On Tue 19-04-22 20:22:34, Miaohe Lin wrote: > Since commit e5947d23edd8 ("mm: mempolicy: don't have to split pmd for > huge zero page"), THP is never splited in queue_pages_pmd. Thus 2 is > never returned now. We can remove such unnecessary ret != 2 check and > clean up the relevant comment. Minor improvements in readability. > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Michal Hocko <mhocko@suse.com> Thanks! > --- > mm/mempolicy.c | 12 +++--------- > 1 file changed, 3 insertions(+), 9 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index 75a8b247f631..3934476fb708 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -441,12 +441,11 @@ static inline bool queue_pages_required(struct page *page, > } > > /* > - * queue_pages_pmd() has four possible return values: > + * queue_pages_pmd() has three possible return values: > * 0 - pages are placed on the right node or queued successfully, or > * special page is met, i.e. huge zero page. > * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were > * specified. > - * 2 - THP was split. > * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an > * existing page was already on a node that does not follow the > * policy. > @@ -508,18 +507,13 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr, > struct page *page; > struct queue_pages *qp = walk->private; > unsigned long flags = qp->flags; > - int ret; > bool has_unmovable = false; > pte_t *pte, *mapped_pte; > spinlock_t *ptl; > > ptl = pmd_trans_huge_lock(pmd, vma); > - if (ptl) { > - ret = queue_pages_pmd(pmd, ptl, addr, end, walk); > - if (ret != 2) > - return ret; > - } > - /* THP was split, fall through to pte walk */ > + if (ptl) > + return queue_pages_pmd(pmd, ptl, addr, end, walk); > > if (pmd_trans_unstable(pmd)) > return 0; > -- > 2.23.0
On Tue, 19 Apr 2022, Miaohe Lin wrote: > Since commit e5947d23edd8 ("mm: mempolicy: don't have to split pmd for > huge zero page"), THP is never splited in queue_pages_pmd. Thus 2 is > never returned now. We can remove such unnecessary ret != 2 check and > clean up the relevant comment. Minor improvements in readability. > > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: David Rientjes <rientjes@google.com>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 75a8b247f631..3934476fb708 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -441,12 +441,11 @@ static inline bool queue_pages_required(struct page *page, } /* - * queue_pages_pmd() has four possible return values: + * queue_pages_pmd() has three possible return values: * 0 - pages are placed on the right node or queued successfully, or * special page is met, i.e. huge zero page. * 1 - there is unmovable page, and MPOL_MF_MOVE* & MPOL_MF_STRICT were * specified. - * 2 - THP was split. * -EIO - is migration entry or only MPOL_MF_STRICT was specified and an * existing page was already on a node that does not follow the * policy. @@ -508,18 +507,13 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr, struct page *page; struct queue_pages *qp = walk->private; unsigned long flags = qp->flags; - int ret; bool has_unmovable = false; pte_t *pte, *mapped_pte; spinlock_t *ptl; ptl = pmd_trans_huge_lock(pmd, vma); - if (ptl) { - ret = queue_pages_pmd(pmd, ptl, addr, end, walk); - if (ret != 2) - return ret; - } - /* THP was split, fall through to pte walk */ + if (ptl) + return queue_pages_pmd(pmd, ptl, addr, end, walk); if (pmd_trans_unstable(pmd)) return 0;
Since commit e5947d23edd8 ("mm: mempolicy: don't have to split pmd for huge zero page"), THP is never splited in queue_pages_pmd. Thus 2 is never returned now. We can remove such unnecessary ret != 2 check and clean up the relevant comment. Minor improvements in readability. Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> --- mm/mempolicy.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)