Messages in this thread | | | Date | Wed, 23 Jan 2008 11:04:09 +0100 | From | "Loïc Grenié" <> | Subject | Re: vmalloc_32 and SLAB incompatible in 2.6.23.9 |
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23 Jan 2008 10:35:28 +0100, Andi Kleen <andi@firstfloor.org>: > "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.
vmalloc_32 is using __vmalloc. I am much too ignorant to try and change anything in mm/*.[ch]. If vmalloc_32 is incompatible with sl[aou]b, should'nt it be either modified or removed ?
Thanks,
Loïc Grenié -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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