On 2010-10-19 12.22, Gilles Chanteperdrix wrote: > Daniel Jacques (Alten) wrote: >> Hi, >> >> I noticed some allocation failure using kmalloc in case of GFP_DMA32 with >> big size, even if I modified the CONFIG_FORCE_MAX_ZONEORDER to be coherent >> with my max size (32MB). >> I don't know the reason of this failure. I am interesting by any idea about >> this point ... >> Meanwhile, to avoid this trouble I performed the following additional patch >> in ksrc/nucleus/heap.c to force using of __get_free_pages instead of kmalloc >> in case of GFP_DMA32 flag. >> Jacques > > At this point, the problem seems to be in linux code. So, there should > be no need to modify xenomai code. Are you sure that kmalloc does not > fail due to fragmentation? I have some vague recollection that dmaable allocations larger than 2MB should be done by pci_alloc_consistent and similar (see Documentation/DMA-mapping.txt or Documentation/DMA-API-HOWTO.txt in newer kernels)
/Anders -- Anders Blomdell Email: [email protected] Department of Automatic Control Lund University Phone: +46 46 222 4625 P.O. Box 118 Fax: +46 46 138118 SE-221 00 Lund, Sweden _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
