| Message ID | 20220913195508.3511038-3-opendmb@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: introduce Designated Movable Blocks | expand |
On 09/13/22 12:54, Doug Berger wrote: > When demoting a hugepage to a smaller order, the number of pages > added to the target hstate will be the size of the large page > divided by the size of the smaller page. > > Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") > Signed-off-by: Doug Berger <opendmb@gmail.com> > --- > mm/hugetlb.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index e070b8593b37..79949893ac12 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) > * based on pool changes for the demoted page. > */ > h->max_huge_pages--; > - target_hstate->max_huge_pages += pages_per_huge_page(h); > + target_hstate->max_huge_pages += pages_per_huge_page(h) / > + pages_per_huge_page(target_hstate); > > return rc; > } This has already been fixed here, https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/
On 9/14/22 10:23, Mike Kravetz wrote: > On 09/13/22 12:54, Doug Berger wrote: >> When demoting a hugepage to a smaller order, the number of pages >> added to the target hstate will be the size of the large page >> divided by the size of the smaller page. >> >> Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") >> Signed-off-by: Doug Berger <opendmb@gmail.com> >> --- >> mm/hugetlb.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index e070b8593b37..79949893ac12 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) >> * based on pool changes for the demoted page. >> */ >> h->max_huge_pages--; >> - target_hstate->max_huge_pages += pages_per_huge_page(h); >> + target_hstate->max_huge_pages += pages_per_huge_page(h) / >> + pages_per_huge_page(target_hstate); >> >> return rc; >> } > > This has already been fixed here, > > https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/ > Could we slap the Fixes tag when this Miaohe's patch series gets accepted since the offending commit is in v5.16 and beyond. Thanks!
On 9/14/2022 10:23 AM, Mike Kravetz wrote: > On 09/13/22 12:54, Doug Berger wrote: >> When demoting a hugepage to a smaller order, the number of pages >> added to the target hstate will be the size of the large page >> divided by the size of the smaller page. >> >> Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") >> Signed-off-by: Doug Berger <opendmb@gmail.com> >> --- >> mm/hugetlb.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index e070b8593b37..79949893ac12 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) >> * based on pool changes for the demoted page. >> */ >> h->max_huge_pages--; >> - target_hstate->max_huge_pages += pages_per_huge_page(h); >> + target_hstate->max_huge_pages += pages_per_huge_page(h) / >> + pages_per_huge_page(target_hstate); >> >> return rc; >> } > > This has already been fixed here, > > https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/ > Excellent! Thanks for the pointer and sorry for the noise. -Doug
On 09/14/22 10:26, Florian Fainelli wrote: > On 9/14/22 10:23, Mike Kravetz wrote: > > On 09/13/22 12:54, Doug Berger wrote: > > > When demoting a hugepage to a smaller order, the number of pages > > > added to the target hstate will be the size of the large page > > > divided by the size of the smaller page. > > > > > > Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") > > > Signed-off-by: Doug Berger <opendmb@gmail.com> > > > --- > > > mm/hugetlb.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > > index e070b8593b37..79949893ac12 100644 > > > --- a/mm/hugetlb.c > > > +++ b/mm/hugetlb.c > > > @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) > > > * based on pool changes for the demoted page. > > > */ > > > h->max_huge_pages--; > > > - target_hstate->max_huge_pages += pages_per_huge_page(h); > > > + target_hstate->max_huge_pages += pages_per_huge_page(h) / > > > + pages_per_huge_page(target_hstate); > > > return rc; > > > } > > > > This has already been fixed here, > > > > https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/ > > > > Could we slap the Fixes tag when this Miaohe's patch series gets accepted > since the offending commit is in v5.16 and beyond. Thanks! We could. However, this fix/change does not really have any impact on the way code functions (unless I am mistaken). See my analysis at, https://lore.kernel.org/linux-mm/YvwfvxXewnZpHQcz@monkey/
On Wed, 14 Sep 2022 10:23:05 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote: > On 09/13/22 12:54, Doug Berger wrote: > > When demoting a hugepage to a smaller order, the number of pages > > added to the target hstate will be the size of the large page > > divided by the size of the smaller page. > > > > Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") > > Signed-off-by: Doug Berger <opendmb@gmail.com> > > --- > > mm/hugetlb.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > index e070b8593b37..79949893ac12 100644 > > --- a/mm/hugetlb.c > > +++ b/mm/hugetlb.c > > @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) > > * based on pool changes for the demoted page. > > */ > > h->max_huge_pages--; > > - target_hstate->max_huge_pages += pages_per_huge_page(h); > > + target_hstate->max_huge_pages += pages_per_huge_page(h) / > > + pages_per_huge_page(target_hstate); > > > > return rc; > > } > > This has already been fixed here, > > https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/ Neither version tells us the user-visible runtime effects of the change :(
On 09/14/22 13:58, Andrew Morton wrote: > On Wed, 14 Sep 2022 10:23:05 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote: > > > On 09/13/22 12:54, Doug Berger wrote: > > > When demoting a hugepage to a smaller order, the number of pages > > > added to the target hstate will be the size of the large page > > > divided by the size of the smaller page. > > > > > > Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") > > > Signed-off-by: Doug Berger <opendmb@gmail.com> > > > --- > > > mm/hugetlb.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > > > index e070b8593b37..79949893ac12 100644 > > > --- a/mm/hugetlb.c > > > +++ b/mm/hugetlb.c > > > @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) > > > * based on pool changes for the demoted page. > > > */ > > > h->max_huge_pages--; > > > - target_hstate->max_huge_pages += pages_per_huge_page(h); > > > + target_hstate->max_huge_pages += pages_per_huge_page(h) / > > > + pages_per_huge_page(target_hstate); > > > > > > return rc; > > > } > > > > This has already been fixed here, > > > > https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@huawei.com/ > > Neither version tells us the user-visible runtime effects of the change :( Sorry, I should have pushed harder on this with Miaohe's patch. There are no user-visible runtime effects. In fact, this change really causes no functional change (unless I am mistaken and Miaohe did not correct me). max_huge_pages is not used again until it is reset. See my explanation at: https://lore.kernel.org/linux-mm/YvwfvxXewnZpHQcz@monkey/
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e070b8593b37..79949893ac12 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) * based on pool changes for the demoted page. */ h->max_huge_pages--; - target_hstate->max_huge_pages += pages_per_huge_page(h); + target_hstate->max_huge_pages += pages_per_huge_page(h) / + pages_per_huge_page(target_hstate); return rc; }
When demoting a hugepage to a smaller order, the number of pages added to the target hstate will be the size of the large page divided by the size of the smaller page. Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") Signed-off-by: Doug Berger <opendmb@gmail.com> --- mm/hugetlb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)