Messages in this thread | | | Date | Wed, 22 Jul 2009 10:27:00 +0200 | From | Thomas Hellström <> | Subject | Re: TTM page pool allocator |
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Jerome Glisse wrote: > On Thu, 2009-06-25 at 17:53 +0200, Thomas Hellström wrote: > >> Jerome Glisse skrev: >> >>> Hi, >>> >>> Thomas i attach a reworked page pool allocator based on Dave works, >>> this one should be ok with ttm cache status tracking. It definitely >>> helps on AGP system, now the bottleneck is in mesa vertex's dma >>> allocation. >>> >>> Cheers, >>> Jerome >>> >>> >> Hi, Jerome! >> In general it looks very good. Some things that need fixing: >> >> 1) We must have a way to hand back pages. I still not quite understand >> how the shrink callbacks work and whether they are applicable. Another >> scheme would be to free, say 1MB when we have at least 2MB available. >> >> 2) We should avoid including AGP headers if AGP is not configured. >> Either reimplement unmap_page_from_agp or map_page_into_agp or move them >> out from the AGP headers. We've hade complaints before from people with >> AGP free systems that the code doesn't compile. >> >> 3) Since we're allocating (and freeing) in batches we should use the >> set_pages_array() interface to avoid a global tlb flush per page. >> >> 4) We could now skip the ttm_tt_populate() in ttm_tt_set_caching, since >> it will always allocate cached pages and then transition them. >> >> > > Okay 4) is bad, what happens (my brain is a bit meltdown so i might be > wrong) : > 1 - bo get allocated tt->state = unpopulated > 2 - bo is mapped few page are faulted tt->state = unpopulated > 3 - bo is cache transitioned but tt->state == unpopulated but > they are page which have been touch by the cpu so we need > to clflush them and transition them,
Right.
> this never happen if > we don't call ttm_tt_populate and proceed with the remaining > of the cache transitioning functions >
Why can't we just skip ttm_tt_populate and proceed with the remaining of the cache transitioning functions? Then all pages currently allocated to the TTM will be transitioned.
/Thomas
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