Thread (37 messages) 37 messages, 9 authors, 2019-07-08

use exact allocation for dma coherent memory

From: Christoph Hellwig <hch@lst.de>
Date: 2019-06-14 13:47:47
Also in: dri-devel, intel-gfx, linux-iommu, linux-media, linux-mm, linux-rdma, linux-s390, linux-wireless, lkml, netdev

Hi all,

various architectures have used exact memory allocations for dma
allocations for a long time, but x86 and thus the common code based
on it kept using our normal power of two allocator, which tends to
waste a lot of memory for certain allocations.

Switching to a slightly cleaned up alloc_pages_exact is pretty easy,
but it turns out that because we didn't filter valid gfp_t flags
on the DMA allocator, a bunch of drivers were passing __GFP_COMP
to it, which is rather bogus in too many ways to explain.  Arm has
been filtering it for a while, but this series instead tries to fix
the drivers and warn when __GFP_COMP is passed, which makes it much
larger than just adding the functionality.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help