Messages in this thread | | | Subject | Re: vmalloc_32 and SLAB incompatible in 2.6.23.9 | From | Andi Kleen <> | Date | 23 Jan 2008 10:35:28 +0100 |
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"Loïc Grenié" <loic.grenie@gmail.com> writes:
> Since GFP_DMA32 is not considered a valid flag, vmalloc_32 and > SLAB are incompatible in kernel 2.6.23.9 (and probably later ones). > It might be as simple as adding GFP_DMA32 everywhere where > GFP_DMA is used in mm/slab.c, but I don't dare do it. I personally > switched to SLUB.
I don't think it would really work for slub either.
If you look at /proc/slabinfo you see that there are separate DMA caches. That is because sl[abo]b all cache objects and if the objects have different requirements (like GFP_DMA, GFP_DMA32, GFP_KERNEL) they would need different caches. Otherwise you risk getting later objects originally allocated with the wrong flags.
To make GFP_DMA32 work would require adding another set of DMA32 caches to all kmalloc caches etc or a separate one for each custom kmem cache that you use that only gets _DMA32 objects.
Better just use __get_free_pages() directly.
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