linux_dsm_epyc7002/arch/powerpc
Aneesh Kumar K.V 691e95fd73 powerpc/mm/thp: Make page table walk safe against thp split/collapse
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>
2015-04-17 11:23:39 +10:00
..
boot powerpc: Remove the celleb support 2015-04-07 17:15:13 +10:00
configs powerpc: Remove the celleb support 2015-04-07 17:15:13 +10:00
crypto crypto: powerpc - move files to fix build error 2015-03-09 21:06:19 +11:00
include powerpc/mm/thp: Make page table walk safe against thp split/collapse 2015-04-17 11:23:39 +10:00
kernel powerpc/mm/thp: Make page table walk safe against thp split/collapse 2015-04-17 11:23:39 +10:00
kvm powerpc/mm/thp: Make page table walk safe against thp split/collapse 2015-04-17 11:23:39 +10:00
lib powerpc: Replace mem_init_done with slab_is_available() 2015-04-10 20:02:48 +10:00
math-emu powerpc: Correct emulated mtfsf instruction 2014-04-07 10:33:11 +10:00
mm powerpc/mm/thp: Make page table walk safe against thp split/collapse 2015-04-17 11:23:39 +10:00
net ppc: bpf: Add SKF_AD_CPU for ppc32 2015-02-20 15:19:43 -05:00
oprofile powerpc updates for 3.19 2014-12-11 17:48:14 -08:00
perf powerpc/mm/thp: Make page table walk safe against thp split/collapse 2015-04-17 11:23:39 +10:00
platforms powerpc updates for 4.1 2015-04-16 13:53:32 -05:00
sysdev powerpc: dart_iommu: Remove check for controller_ops == NULL case 2015-04-11 20:49:19 +10:00
xmon powerpc updates for 3.20 2015-02-11 18:15:38 -08:00
Kconfig powerpc updates for 4.1 2015-04-16 13:53:32 -05:00
Kconfig.debug powerpc: Remove the celleb support 2015-04-07 17:15:13 +10:00
Makefile powerpc: Convert relocs_check to a shell script using grep 2015-03-23 14:47:39 +11:00
relocs_check.sh powerpc: Convert relocs_check to a shell script using grep 2015-03-23 14:47:39 +11:00