Messages in this thread | | | Date | Fri, 24 Aug 2012 10:07:00 +0200 | From | Heiko Carstens <> | Subject | Re: [RFC patch 7/7] thp, s390: architecture backend for thp on System z |
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On Thu, Aug 23, 2012 at 07:17:40PM +0200, Gerald Schaefer wrote: > +#define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG > +static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma, > + unsigned long address, > + pmd_t *pmdp) > +{ > + int rc = 0; > + int counter = PTRS_PER_PTE; > + unsigned long pmd_addr = pmd_val(*pmdp) & HPAGE_MASK; > + > + asm volatile( > + "0: rrbe 0,%2\n" > + " la %2,0(%3,%2)\n" > + " brc 12,1f\n" > + " lhi %0,1\n" > + "1: brct %1,0b\n" > + : "+d" (rc), "+d" (counter), "+a" (pmd_addr) > + : "a" (4096UL): "cc" ); > + return rc; > +}
Just a small side note: given that rrbe is very expensive you probably should extend this function so it makes use of the rrbm instruction if available.
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