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authorMichael Brown <mcb30@ipxe.org>2012-06-29 16:07:12 +0100
committerMichael Brown <mcb30@ipxe.org>2012-06-29 16:07:12 +0100
commita5c016d93ee24e851cd8752b014170a308f231da (patch)
tree5dc41c4838463a891de906ac91c25917d32c5a73 /src/include/ipxe/iobuf.h
parent9a8c6b00d4433eb5c24f50c0c4a93c127d77def0 (diff)
downloadipxe-a5c016d93ee24e851cd8752b014170a308f231da.tar.gz
[iobuf] Relax alignment requirement for small I/O buffers
iPXE currently aligns all I/O buffers on a 2kB boundary. This is overkill for transmitted packets, which are typically much smaller than 2kB. Align I/O buffers on their own size. This reduces the alignment requirement for small buffers, while preserving the guarantee that I/O buffers will never cross boundaries that might cause problems for some DMA engines. Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/include/ipxe/iobuf.h')
-rw-r--r--src/include/ipxe/iobuf.h11
1 files changed, 0 insertions, 11 deletions
diff --git a/src/include/ipxe/iobuf.h b/src/include/ipxe/iobuf.h
index 82c8b8896..8134ae76a 100644
--- a/src/include/ipxe/iobuf.h
+++ b/src/include/ipxe/iobuf.h
@@ -14,17 +14,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
#include <ipxe/list.h>
/**
- * I/O buffer alignment
- *
- * I/O buffers allocated via alloc_iob() are guaranteed to be
- * physically aligned to this boundary. Some cards cannot DMA across
- * a 4kB boundary. With a standard Ethernet MTU, aligning to a 2kB
- * boundary is sufficient to guarantee no 4kB boundary crossings. For
- * a jumbo Ethernet MTU, a packet may be larger than 4kB anyway.
- */
-#define IOB_ALIGN 2048
-
-/**
* Minimum I/O buffer length
*
* alloc_iob() will round up the allocated length to this size if