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691e95fd73
We can disable a THP split or a hugepage collapse by disabling irq. We do send IPI to all the cpus in the early part of split/collapse, and disabling local irq ensure we don't make progress with split/collapse. If the THP is getting split we return NULL from find_linux_pte_or_hugepte(). For all the current callers it should be ok. We need to be careful if we want to use returned pte_t pointer outside the irq disabled region. W.r.t to THP split, the pfn remains the same, but then a hugepage collapse will result in a pfn change. There are few steps we can take to avoid a hugepage collapse.One way is to take page reference inside the irq disable region. Other option is to take mmap_sem so that a parallel collapse will not happen. We can also disable collapse by taking pmd_lock. Another method used by kvm subsystem is to check whether we had a mmu_notifer update in between using mmu_notifier_retry(). Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
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| .. | ||
| req-gen | ||
| bhrb.S | ||
| callchain.c | ||
| core-book3s.c | ||
| core-fsl-emb.c | ||
| e500-pmu.c | ||
| e6500-pmu.c | ||
| hv-24x7-catalog.h | ||
| hv-24x7-domains.h | ||
| hv-24x7.c | ||
| hv-24x7.h | ||
| hv-common.c | ||
| hv-common.h | ||
| hv-gpci-requests.h | ||
| hv-gpci.c | ||
| hv-gpci.h | ||
| Makefile | ||
| mpc7450-pmu.c | ||
| power4-pmu.c | ||
| power5+-pmu.c | ||
| power5-pmu.c | ||
| power6-pmu.c | ||
| power7-events-list.h | ||
| power7-pmu.c | ||
| power8-pmu.c | ||
| ppc970-pmu.c | ||