Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-20 Thread Oliver
On Thu, Mar 21, 2019 at 7:57 AM Dan Williams wrote: > > On Wed, Mar 20, 2019 at 8:34 AM Dan Williams wrote: > > > > On Wed, Mar 20, 2019 at 1:09 AM Aneesh Kumar K.V > > wrote: > > > > > > Aneesh Kumar K.V writes: > > > > > > > Dan Williams writes: > > > > > > > >> > > > >>> Now what will be

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-20 Thread Dan Williams
On Wed, Mar 20, 2019 at 8:34 AM Dan Williams wrote: > > On Wed, Mar 20, 2019 at 1:09 AM Aneesh Kumar K.V > wrote: > > > > Aneesh Kumar K.V writes: > > > > > Dan Williams writes: > > > > > >> > > >>> Now what will be page size used for mapping vmemmap? > > >> > > >> That's up to the

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-20 Thread Dan Williams
On Wed, Mar 20, 2019 at 1:09 AM Aneesh Kumar K.V wrote: > > Aneesh Kumar K.V writes: > > > Dan Williams writes: > > > >> > >>> Now what will be page size used for mapping vmemmap? > >> > >> That's up to the architecture's vmemmap_populate() implementation. > >> > >>> Architectures > >>>

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-20 Thread Aneesh Kumar K.V
Aneesh Kumar K.V writes: > Dan Williams writes: > >> >>> Now what will be page size used for mapping vmemmap? >> >> That's up to the architecture's vmemmap_populate() implementation. >> >>> Architectures >>> possibly will use PMD_SIZE mapping if supported for vmemmap. Now a >>> device-dax with

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-20 Thread Aneesh Kumar K.V
Dan Williams writes: > >> Now what will be page size used for mapping vmemmap? > > That's up to the architecture's vmemmap_populate() implementation. > >> Architectures >> possibly will use PMD_SIZE mapping if supported for vmemmap. Now a >> device-dax with struct page in the device will have

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-19 Thread Dan Williams
On Tue, Mar 19, 2019 at 1:45 AM Kirill A. Shutemov wrote: > > On Wed, Mar 13, 2019 at 09:07:13AM -0700, Dan Williams wrote: > > On Wed, Mar 6, 2019 at 4:46 AM Aneesh Kumar K.V > > wrote: > > > > > > On 3/6/19 5:14 PM, Michal Suchánek wrote: > > > > On Wed, 06 Mar 2019 14:47:33 +0530 > > > >

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-19 Thread Kirill A. Shutemov
On Wed, Mar 13, 2019 at 09:07:13AM -0700, Dan Williams wrote: > On Wed, Mar 6, 2019 at 4:46 AM Aneesh Kumar K.V > wrote: > > > > On 3/6/19 5:14 PM, Michal Suchánek wrote: > > > On Wed, 06 Mar 2019 14:47:33 +0530 > > > "Aneesh Kumar K.V" wrote: > > > > > >> Dan Williams writes: > > >> > > >>> On

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-13 Thread Dan Williams
On Wed, Mar 13, 2019 at 8:45 PM Aneesh Kumar K.V wrote: [..] > >> Now w.r.t to failures, can device-dax do an opportunistic huge page > >> usage? > > > > device-dax explicitly disclaims the ability to do opportunistic mappings. > > > >> I haven't looked at the device-dax details fully yet. Do we

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-13 Thread Aneesh Kumar K.V
Dan Williams writes: > On Wed, Mar 6, 2019 at 1:18 AM Aneesh Kumar K.V > wrote: >> >> Dan Williams writes: >> >> > On Thu, Feb 28, 2019 at 1:40 AM Oliver wrote: >> >> >> >> On Thu, Feb 28, 2019 at 7:35 PM Aneesh Kumar K.V >> >> wrote: >> >> > >> >> > Add a flag to indicate the ability to do

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-13 Thread Dan Williams
On Wed, Mar 6, 2019 at 4:46 AM Aneesh Kumar K.V wrote: > > On 3/6/19 5:14 PM, Michal Suchánek wrote: > > On Wed, 06 Mar 2019 14:47:33 +0530 > > "Aneesh Kumar K.V" wrote: > > > >> Dan Williams writes: > >> > >>> On Thu, Feb 28, 2019 at 1:40 AM Oliver wrote: > > On Thu, Feb 28, 2019 at

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-13 Thread Dan Williams
On Wed, Mar 6, 2019 at 1:18 AM Aneesh Kumar K.V wrote: > > Dan Williams writes: > > > On Thu, Feb 28, 2019 at 1:40 AM Oliver wrote: > >> > >> On Thu, Feb 28, 2019 at 7:35 PM Aneesh Kumar K.V > >> wrote: > >> > > >> > Add a flag to indicate the ability to do huge page dax mapping. On > >> >

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-06 Thread Aneesh Kumar K.V
On 3/6/19 5:14 PM, Michal Suchánek wrote: On Wed, 06 Mar 2019 14:47:33 +0530 "Aneesh Kumar K.V" wrote: Dan Williams writes: On Thu, Feb 28, 2019 at 1:40 AM Oliver wrote: On Thu, Feb 28, 2019 at 7:35 PM Aneesh Kumar K.V wrote: Also even if the user decided to not use THP, by echo

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-06 Thread Kirill A. Shutemov
On Wed, Mar 06, 2019 at 06:15:25PM +0530, Aneesh Kumar K.V wrote: > On 3/6/19 5:14 PM, Michal Suchánek wrote: > > On Wed, 06 Mar 2019 14:47:33 +0530 > > "Aneesh Kumar K.V" wrote: > > > > > Dan Williams writes: > > > > > > > On Thu, Feb 28, 2019 at 1:40 AM Oliver wrote: > > > > > > > > > > On

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-06 Thread Michal Suchánek
On Wed, 06 Mar 2019 14:47:33 +0530 "Aneesh Kumar K.V" wrote: > Dan Williams writes: > > > On Thu, Feb 28, 2019 at 1:40 AM Oliver wrote: > >> > >> On Thu, Feb 28, 2019 at 7:35 PM Aneesh Kumar K.V > >> wrote: > Also even if the user decided to not use THP, by > echo "never" >

Re: [PATCH 2/2] mm/dax: Don't enable huge dax mapping by default

2019-03-06 Thread Aneesh Kumar K.V
Dan Williams writes: > On Thu, Feb 28, 2019 at 1:40 AM Oliver wrote: >> >> On Thu, Feb 28, 2019 at 7:35 PM Aneesh Kumar K.V >> wrote: >> > >> > Add a flag to indicate the ability to do huge page dax mapping. On >> > architecture >> > like ppc64, the hypervisor can disable huge page support in