* [PATCH] ppc32: fix ptep_test_and_clear_young
@ 2005-02-21 5:09 Benjamin Herrenschmidt
0 siblings, 0 replies; only message in thread
From: Benjamin Herrenschmidt @ 2005-02-21 5:09 UTC (permalink / raw)
To: Linus Torvalds, Andrew Morton; +Cc: linuxppc-dev list
Hi !
ppc32's implementation of ptep_test_and_clear_young() has a logic error
which makes it fail to flush the hash table. Thus PAGE_ACCESSED is
almost never set again after beeing cleared (unless something else cause
that hash entry to be flushed).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Index: linux-work/include/asm-ppc/pgtable.h
===================================================================
--- linux-work.orig/include/asm-ppc/pgtable.h 2005-01-24 17:09:50.000000000 +1100
+++ linux-work/include/asm-ppc/pgtable.h 2005-02-21 16:00:26.000000000 +1100
@@ -560,12 +560,12 @@
static inline int ptep_test_and_clear_young(pte_t *ptep)
{
unsigned long old;
- old = (pte_update(ptep, _PAGE_ACCESSED, 0) & _PAGE_ACCESSED);
+ old = pte_update(ptep, _PAGE_ACCESSED, 0);
#if _PAGE_HASHPTE != 0
if (old & _PAGE_HASHPTE)
flush_hash_one_pte(ptep);
#endif
- return old != 0;
+ return (old & _PAGE_ACCESSED) != 0;
}
static inline int ptep_test_and_clear_dirty(pte_t *ptep)
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