[lkml]   [2018]   [Feb]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: staging: ion: ION allocation fall back order depends on heap linkage order

On 02/07/2018 04:58 PM, Laura Abbott wrote:
> On 02/06/2018 11:05 PM, Alexey Skidanov wrote:
>>> Yup, you've hit upon a key problem. Having fallbacks be stable
>>> was always a problem and the recommendation these days is to
>>> not rely on them. You can specify a heap at a time and fallback
>>> manually if you want that behavior.
>>> If you have a proposal to make fallbacks work reliably without
>>> overly complicating the ABI I'm happy to review it.
>>> Thanks,
>>> Laura
>> I think it's possible to "automate" the "manual fallback" behavior. But
>> the real issues is using heap id to specify the particular heap object.
>> Current API (allocation IOCTL) requires to specify the particular heap
>> object by using heap id. From the other hand, the user space doesn't
>> control the heaps creation order and heap id assignment. So it may be
>> tricky, especially when more than one object of the same heap type is
>> created automatically.
>> Thanks,
>> Alexey
> The query ioctl is designed to get the heap ID information without
> needing to rely on the linking order or anything else defined in
> the kernel.
> Thanks,
> Laura

That is true. But if we have 2 *automatically created* heaps of the same
type, how userspace can distinguish between them?


 \ /
  Last update: 2018-02-07 16:10    [W:0.038 / U:36.076 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site