On Sat, 2012-03-17 at 14:14 -0700, Linus Torvalds wrote: > On Sat, Mar 17, 2012 at 1:23 PM, Dave Airlie <airlied@xxxxxxxxx> wrote: > > > > I did however get a flashback in google to this: > > > > http://lists.fedoraproject.org/pipermail/scm-commits/2010-July/456636.html > > > > Linus don't think we ever did work out why that worked, I wonder if we > > lost something after that. > > Hmm. Maybe we should stop making the default gfp_mask be > GFP_HIGHMEM_MOVABLE (see inode_init_always() in fs/inode.c), and > instead add the _MOVABLE flag only for mappings that use > "generic_file_mmap()". > > It does sound a bit scary to just make default mappings use MOVABLE > pages, when we know that can be incorrect for some cases. > > But that would require that filesystems like ext4 etc that don't just > use the generic_file_mmap() function would have add do that MOVABLE > thing on their own. And the *normal* case is certainly that pages are > movable and putting them in themovable zone should be ok. It's just > *not* ok if you also map them into some hardware GTT thing or just > otherwise keep track of the pages directly, like DRI does. > > The other possibility is to just make this a shm thing, since it's > generally that layer that has the case of "pages allocated with the > mapping gfp masks". Hugh Dickins clearly tried to make sure that the > DRM initialization of the gfp mask was honored, but maybe there is > some case where it is missed. Hugh added a mapping_set_gfp_mask() to > i915_gem_alloc_object(), but maybe we have i915 shmem mappings that > get set up through some other path. > > What about the ttm swap storage thing, for example? That also does > shmem_file_setup(), without limiting the pages. But I don't think i915 > uses ttm, right? It's not an issue for ttm, as we never us page allocated through shmem for the hw. We use shmem to swapout buffer object (ttm_tt_swapout func in ttm_tt.c). Cheers, Jerome _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
