Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/page-flags.h | 51 ++++++++++++++++++++++++++++++++++++--
1 file changed, 49 insertions(+), 2 deletions(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 1c3b6e5c8bfd..15ba61996a78 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -107,7 +107,7 @@ enum pageflags {
PG_workingset,
PG_waiters, /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
PG_error,
- PG_slab,
+ PG_xyzzy, /* Magic. The other flags change meaning */
PG_owner_priv_1, /* Owner use. If pagecache, fs may use*/
PG_arch_1,
PG_reserved,
@@ -140,6 +140,9 @@ enum pageflags {
#endif
__NR_PAGEFLAGS,
+ /* xyzzy flags */
+ PG_slab = PG_owner_priv_1,
+
PG_readahead = PG_reclaim,
/* Filesystems */
@@ -425,10 +428,54 @@ PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
TESTCLEARFLAG(Active, active, PF_HEAD)
PAGEFLAG(Workingset, workingset, PF_HEAD)
TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
-__PAGEFLAG(Slab, slab, PF_NO_TAIL)
__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
PAGEFLAG(Checked, checked, PF_NO_COMPOUND) /* Used by some filesystems */
+#define XYZZY(name) ((1UL << PG_xyzzy) | (1UL << PG_##name))
+
+static __always_inline bool folio_test_slab(struct folio *folio)
+{
+ return (*folio_flags(folio, 0) & XYZZY(slab)) == XYZZY(slab);
+}
+
+static __always_inline bool PageSlab(struct page *page)
+{
+ return folio_test_slab(page_folio(page));
+}
+
+static __always_inline void folio_set_slab(struct folio *folio)
+{
+ unsigned long flags, *p = folio_flags(folio, 0);
+
+ do {
+ flags = READ_ONCE(*p);
+ } while (cmpxchg(p, flags, flags | XYZZY(slab)) != flags);
+}
+
+static __always_inline void folio_clear_slab(struct folio *folio)
+{
+ unsigned long flags, *p = folio_flags(folio, 0);
+
+ do {
+ flags = READ_ONCE(*p);
+ } while (cmpxchg(p, flags, flags & ~XYZZY(slab)) != flags);
+}
+
+static __always_inline void __folio_set_slab(struct folio *folio)
+{
+ *folio_flags(folio, 0) |= XYZZY(slab);
+}
+
+static __always_inline void __SetPageSlab(struct page *page)
+{
+ page->flags |= XYZZY(slab);
+}
+
+static __always_inline void __folio_clear_slab(struct folio *folio)
+{
+ *folio_flags(folio, 0) &= ~XYZZY(slab);
+}
+
/* Xen */
PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
--
2.34.1
