include/linux/hugetlb.h | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-)
All users have been converted to use the folio version of these macros,
we can safely remove the page based interface.
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
include/linux/hugetlb.h | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 77b30a8c6076b..c99ed9d2192d8 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -657,18 +657,14 @@ static __always_inline \
void folio_set_hugetlb_##flname(struct folio *folio) \
{ void *private = &folio->private; \
set_bit(HPG_##flname, private); \
- } \
-static inline void SetHPage##uname(struct page *page) \
- { set_bit(HPG_##flname, &(page->private)); }
+ }
#define CLEARHPAGEFLAG(uname, flname) \
static __always_inline \
void folio_clear_hugetlb_##flname(struct folio *folio) \
{ void *private = &folio->private; \
clear_bit(HPG_##flname, private); \
- } \
-static inline void ClearHPage##uname(struct page *page) \
- { clear_bit(HPG_##flname, &(page->private)); }
+ }
#else
#define TESTHPAGEFLAG(uname, flname) \
static inline bool \
@@ -680,15 +676,11 @@ static inline int HPage##uname(struct page *page) \
#define SETHPAGEFLAG(uname, flname) \
static inline void \
folio_set_hugetlb_##flname(struct folio *folio) \
- { } \
-static inline void SetHPage##uname(struct page *page) \
{ }
#define CLEARHPAGEFLAG(uname, flname) \
static inline void \
folio_clear_hugetlb_##flname(struct folio *folio) \
- { } \
-static inline void ClearHPage##uname(struct page *page) \
{ }
#endif
--
2.45.1On Mon, May 20, 2024 at 03:44:07PM -0700, Sidhartha Kumar wrote: > All users have been converted to use the folio version of these macros, > we can safely remove the page based interface. > > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> -- Oscar Salvador SUSE Labs
On 21.05.24 00:44, Sidhartha Kumar wrote: > All users have been converted to use the folio version of these macros, > we can safely remove the page based interface. > > Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> > --- Reviewed-by: David Hildenbrand <david@redhat.com> -- Cheers, David / dhildenb
On Mon, May 20, 2024 at 03:44:07PM -0700, Sidhartha Kumar wrote: > All users have been converted to use the folio version of these macros, > we can safely remove the page based interface. Yay! Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
On 5/20/24 4:30 PM, Matthew Wilcox wrote: > On Mon, May 20, 2024 at 03:44:07PM -0700, Sidhartha Kumar wrote: >> All users have been converted to use the folio version of these macros, >> we can safely remove the page based interface. > > Yay! > > Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> > > There is only one remaining user of page-based Test version of these macros. in mm/memory-hotplug.c: if (!PageHuge(page)) continue; head = compound_head(page); /* * This test is racy as we hold no reference or lock. The * hugetlb page could have been free'ed and head is no longer * a hugetlb page before the following check. In such unlikely * cases false positives and negatives are possible. Calling * code must deal with these scenarios. */ if (HPageMigratable(head)) goto found; skip = compound_nr(head) - (pfn - page_to_pfn(head)); I've previously sent a patch to convert this to folios[1] but got feedback that it was unsafe. But I'm not sure why replacing compound_head() with page_folio() and using folio_test_hugetlb_migratable(folio) rather than HPageMigratable(head) changes the existing behavior. With no reference or lock, can't the head pointer also be moved and no longer be a part of page like the comment states. So would the folio conversion just be maintaining this level of existing un-safety that the calling code should handle anyways? [1]: https://lore.kernel.org/lkml/Y89DK23hYiLtgGNk@casper.infradead.org/T/#mb3a339b98386b1cd0b87f94f45163756ebd7feaa
On Mon, May 20, 2024 at 04:44:53PM -0700, Sidhartha Kumar wrote: > On 5/20/24 4:30 PM, Matthew Wilcox wrote: > > On Mon, May 20, 2024 at 03:44:07PM -0700, Sidhartha Kumar wrote: > > > All users have been converted to use the folio version of these macros, > > > we can safely remove the page based interface. > > > > Yay! > > > > Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> > > There is only one remaining user of page-based Test version of these macros. > > in mm/memory-hotplug.c: > > if (!PageHuge(page)) > continue; > head = compound_head(page); > /* > * This test is racy as we hold no reference or lock. The > * hugetlb page could have been free'ed and head is no longer > * a hugetlb page before the following check. In such unlikely > * cases false positives and negatives are possible. Calling > * code must deal with these scenarios. > */ > if (HPageMigratable(head)) > goto found; > skip = compound_nr(head) - (pfn - page_to_pfn(head)); > > > I've previously sent a patch to convert this to folios[1] but got feedback > that it was unsafe. But I'm not sure why replacing compound_head() with > page_folio() and using folio_test_hugetlb_migratable(folio) rather than > HPageMigratable(head) changes the existing behavior. With no reference or > lock, can't the head pointer also be moved and no longer be a part of page > like the comment states. So would the folio conversion just be maintaining > this level of existing un-safety that the calling code should handle > anyways? To be fair, that wasn't the last thing I said about that ... https://lore.kernel.org/lkml/Y89DK23hYiLtgGNk@casper.infradead.org/ and looked like David agreed that this was a case where false postive/negative was fine; we were just looking to be right most of the time.
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