Messages in this thread | | | Date | Sat, 8 May 2004 23:45:29 +0100 | From | Russell King <> | Subject | Re: [PATCH] rmap 24 pte_young first |
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On Sat, May 08, 2004 at 11:39:32PM +0100, Hugh Dickins wrote: > rmap 25 of course > > On Sat, 8 May 2004, Christoph Hellwig wrote: > > On Sat, May 08, 2004 at 10:56:26PM +0100, Hugh Dickins wrote: > > > > > > - if (ptep_test_and_clear_young(pte)) > > > + if (pte_young(*pte) && ptep_test_and_clear_young(pte)) > > > > stupid question - shouldn't the pte_young check simply move to > > the beginning of ptep_test_and_clear_young? > > I don't think that would be a good idea. We're used to those > test_and_clear operations being atomic, putting an initial non-atomic > test inside would make it fundamentally non-atomic. We know here that > it's not the end of the world if we miss a racing transition of the > young bit, but it wouldn't be good to hide and force that on others.
EAGAIN.
include/asm-generic/pgtable.h:
#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG static inline int ptep_test_and_clear_young(pte_t *ptep) { pte_t pte = *ptep; if (!pte_young(pte)) return 0; set_pte(ptep, pte_mkold(pte)); return 1; } #endif
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/ 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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