Re: [PATCH v5 07/11] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS

2018-03-12 Thread Dan Williams
On Mon, Mar 12, 2018 at 7:17 AM, Jerome Glisse wrote: > On Fri, Mar 09, 2018 at 10:55:26PM -0800, Dan Williams wrote: >> The HMM sub-system extended dev_pagemap to arrange a callback when a >> dev_pagemap managed page is freed. Since a dev_pagemap page is free / >> idle when

Re: [PATCH v5 07/11] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS

2018-03-12 Thread Dan Williams
On Mon, Mar 12, 2018 at 7:17 AM, Jerome Glisse wrote: > On Fri, Mar 09, 2018 at 10:55:26PM -0800, Dan Williams wrote: >> The HMM sub-system extended dev_pagemap to arrange a callback when a >> dev_pagemap managed page is freed. Since a dev_pagemap page is free / >> idle when its reference count

Re: [PATCH v5 07/11] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS

2018-03-12 Thread Jerome Glisse
On Fri, Mar 09, 2018 at 10:55:26PM -0800, Dan Williams wrote: > The HMM sub-system extended dev_pagemap to arrange a callback when a > dev_pagemap managed page is freed. Since a dev_pagemap page is free / > idle when its reference count is 1 it requires an additional branch to > check the

Re: [PATCH v5 07/11] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS

2018-03-12 Thread Jerome Glisse
On Fri, Mar 09, 2018 at 10:55:26PM -0800, Dan Williams wrote: > The HMM sub-system extended dev_pagemap to arrange a callback when a > dev_pagemap managed page is freed. Since a dev_pagemap page is free / > idle when its reference count is 1 it requires an additional branch to > check the

[PATCH v5 07/11] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS

2018-03-09 Thread Dan Williams
The HMM sub-system extended dev_pagemap to arrange a callback when a dev_pagemap managed page is freed. Since a dev_pagemap page is free / idle when its reference count is 1 it requires an additional branch to check the page-type at put_page() time. Given put_page() is a hot-path we do not want to

[PATCH v5 07/11] mm, dev_pagemap: introduce CONFIG_DEV_PAGEMAP_OPS

2018-03-09 Thread Dan Williams
The HMM sub-system extended dev_pagemap to arrange a callback when a dev_pagemap managed page is freed. Since a dev_pagemap page is free / idle when its reference count is 1 it requires an additional branch to check the page-type at put_page() time. Given put_page() is a hot-path we do not want to