Re: [PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-15 Thread Balbir Singh
On Mon, 2016-02-15 at 16:31 +0530, Aneesh Kumar K.V wrote: > Balbir Singh writes: > > > > Now we can't depend for mm_cpumask, a parallel find_linux_pte_hugepte > > > can happen outside that. Now i had a variant for kick_all_cpus_sync that > > > ignored idle cpus. But then that needs more verifica

Re: [PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-15 Thread Aneesh Kumar K.V
Balbir Singh writes: >> Now we can't depend for mm_cpumask, a parallel find_linux_pte_hugepte >> can happen outside that. Now i had a variant for kick_all_cpus_sync that >> ignored idle cpus. But then that needs more verification. >> >> http://article.gmane.org/gmane.linux.ports.ppc.embedded/811

Re: [PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-14 Thread Balbir Singh
> Now we can't depend for mm_cpumask, a parallel find_linux_pte_hugepte > can happen outside that. Now i had a variant for kick_all_cpus_sync that > ignored idle cpus. But then that needs more verification. > > http://article.gmane.org/gmane.linux.ports.ppc.embedded/81105 Can be racy as a CPU mov

Re: [PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-14 Thread Aneesh Kumar K.V
Balbir Singh writes: > On Tue, 2016-02-09 at 06:50 +0530, Aneesh Kumar K.V wrote: >>  >> Also make sure we wait for irq disable section in other cpus to finish >> before flipping a huge pte entry with a regular pmd entry. Code paths >> like find_linux_pte_or_hugepte depend on irq disable to get >

Re: [PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-14 Thread Balbir Singh
On Tue, 2016-02-09 at 06:50 +0530, Aneesh Kumar K.V wrote: >  > Also make sure we wait for irq disable section in other cpus to finish > before flipping a huge pte entry with a regular pmd entry. Code paths > like find_linux_pte_or_hugepte depend on irq disable to get > a stable pte_t pointer. A pa

Re: [V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-13 Thread Aneesh Kumar K.V
Michael Ellerman writes: > On Tue, 2016-09-02 at 01:20:31 UTC, "Aneesh Kumar K.V" wrote: >> With ppc64 we use the deposited pgtable_t to store the hash pte slot >> information. We should not withdraw the deposited pgtable_t without >> marking the pmd none. This ensure that low level hash fault ha

Re: [V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-09 Thread Michael Ellerman
On Tue, 2016-09-02 at 01:20:31 UTC, "Aneesh Kumar K.V" wrote: > With ppc64 we use the deposited pgtable_t to store the hash pte slot > information. We should not withdraw the deposited pgtable_t without > marking the pmd none. This ensure that low level hash fault handling > will skip this huge pte

[PATCH V3] powerpc/mm: Fix Multi hit ERAT cause by recent THP update

2016-02-08 Thread Aneesh Kumar K.V
With ppc64 we use the deposited pgtable_t to store the hash pte slot information. We should not withdraw the deposited pgtable_t without marking the pmd none. This ensure that low level hash fault handling will skip this huge pte and we will handle them at upper levels. Recent change to pmd splitt