Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Thu, Dec 6, 2018 at 5:37 PM Vlastimil Babka wrote: > > On 12/6/18 4:49 AM, Nicolas Boichat wrote: > >> So it would be fine even unchanged. The check would anyway need some > >> more love to catch the same with __GFP_DMA to be consistent and cover > >> all corner cases. > > Yes, the test is not

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On 12/6/18 4:49 AM, Nicolas Boichat wrote: >> So it would be fine even unchanged. The check would anyway need some >> more love to catch the same with __GFP_DMA to be consistent and cover >> all corner cases. > Yes, the test is not complete. If we really wanted this to be > accurate, we'd need to

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Thu, Dec 06, 2018 at 11:55:02AM +0800, Nicolas Boichat wrote: >On Thu, Dec 6, 2018 at 11:32 AM Wei Yang wrote: >> >> On Thu, Dec 06, 2018 at 08:41:36AM +0800, Nicolas Boichat wrote: >> >On Wed, Dec 5, 2018 at 8:18 PM Wei Yang wrote: >> >> >> >> On Wed, Dec 05, 2018 at 03:39:51PM +0800,

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Thu, Dec 6, 2018 at 11:32 AM Wei Yang wrote: > > On Thu, Dec 06, 2018 at 08:41:36AM +0800, Nicolas Boichat wrote: > >On Wed, Dec 5, 2018 at 8:18 PM Wei Yang wrote: > >> > >> On Wed, Dec 05, 2018 at 03:39:51PM +0800, Nicolas Boichat wrote: > >> >On Wed, Dec 5, 2018 at 3:25 PM Wei Yang wrote:

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed, Dec 5, 2018 at 10:02 PM Vlastimil Babka wrote: > > On 12/5/18 6:48 AM, Nicolas Boichat wrote: > > In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate > > data structures smaller than a page with GFP_DMA32 flag. > > > > This change makes it possible to create a custom

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Thu, Dec 06, 2018 at 08:41:36AM +0800, Nicolas Boichat wrote: >On Wed, Dec 5, 2018 at 8:18 PM Wei Yang wrote: >> >> On Wed, Dec 05, 2018 at 03:39:51PM +0800, Nicolas Boichat wrote: >> >On Wed, Dec 5, 2018 at 3:25 PM Wei Yang wrote: >> >> >> >> On Wed, Dec 05, 2018 at 01:48:27PM +0800, Nicolas

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed, Dec 5, 2018 at 8:18 PM Wei Yang wrote: > > On Wed, Dec 05, 2018 at 03:39:51PM +0800, Nicolas Boichat wrote: > >On Wed, Dec 5, 2018 at 3:25 PM Wei Yang wrote: > >> > >> On Wed, Dec 05, 2018 at 01:48:27PM +0800, Nicolas Boichat wrote: > >> >In some cases (e.g. IOMMU ARMv7s page allocator),

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On 12/5/18 6:48 AM, Nicolas Boichat wrote: > In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate > data structures smaller than a page with GFP_DMA32 flag. > > This change makes it possible to create a custom cache in DMA32 zone > using kmem_cache_create, then allocate memory

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed, Dec 05, 2018 at 03:39:51PM +0800, Nicolas Boichat wrote: >On Wed, Dec 5, 2018 at 3:25 PM Wei Yang wrote: >> >> On Wed, Dec 05, 2018 at 01:48:27PM +0800, Nicolas Boichat wrote: >> >In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate >> >data structures smaller than a page

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed 05-12-18 19:01:03, Nicolas Boichat wrote: [...] > > Secondly, why do we need a new sysfs file? Who is going to consume it? > > We have cache_dma, so it seems consistent to add cache_dma32. I wouldn't copy a pattern unless there is an explicit usecase for it. We do expose way too much to

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed, Dec 5, 2018 at 5:56 PM Michal Hocko wrote: > > On Wed 05-12-18 13:48:27, Nicolas Boichat wrote: > > In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate > > data structures smaller than a page with GFP_DMA32 flag. > > > > This change makes it possible to create a custom

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed 05-12-18 13:48:27, Nicolas Boichat wrote: > In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate > data structures smaller than a page with GFP_DMA32 flag. > > This change makes it possible to create a custom cache in DMA32 zone > using kmem_cache_create, then allocate

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed, Dec 05, 2018 at 03:39:51PM +0800, Nicolas Boichat wrote: >On Wed, Dec 5, 2018 at 3:25 PM Wei Yang wrote: >> >> On Wed, Dec 05, 2018 at 01:48:27PM +0800, Nicolas Boichat wrote: >> >In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate >> >data structures smaller than a page

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed, Dec 5, 2018 at 3:25 PM Wei Yang wrote: > > On Wed, Dec 05, 2018 at 01:48:27PM +0800, Nicolas Boichat wrote: > >In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate > >data structures smaller than a page with GFP_DMA32 flag. > > > >This change makes it possible to create a

Re: [PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

On Wed, Dec 05, 2018 at 01:48:27PM +0800, Nicolas Boichat wrote: >In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate >data structures smaller than a page with GFP_DMA32 flag. > >This change makes it possible to create a custom cache in DMA32 zone >using kmem_cache_create, then

[PATCH v4 2/3] mm: Add support for kmem caches in DMA32 zone

In some cases (e.g. IOMMU ARMv7s page allocator), we need to allocate data structures smaller than a page with GFP_DMA32 flag. This change makes it possible to create a custom cache in DMA32 zone using kmem_cache_create, then allocate memory using kmem_cache_alloc. We do not create a DMA32