On Wed, 2009-07-22 at 10:27 +0200, Thomas Hellström wrote: > 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. >
Because not all tt->pages entry have valid page some are null and thus we have to go through the whole table and transition page per page. I did that and quick benchmark showed that it's faster to fully populate and fully transition. Cheers, Jerome ------------------------------------------------------------------------------ -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
