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authorClaudiu Manoil <claudiu.manoil@freescale.com>2013-02-14 05:00:03 (GMT)
committerDavid S. Miller <davem@davemloft.net>2013-02-14 18:32:24 (GMT)
commitb597d20d59b84f0fc3735de75c3efd6e6eb4365d (patch)
tree5ebb34d5ca07986434e233b0f7ecc842e4772917 /REPORTING-BUGS
parent369ec162b30e34c29bef8ec5ce32c40d5697fd64 (diff)
downloadlinux-fsl-qoriq-b597d20d59b84f0fc3735de75c3efd6e6eb4365d.tar.xz
gianfar: Cleanup and optimize struct gfar_private
Group run-time critical fields within the 1st cacheline (32B) followed by the tx|rx_queue reference arrays and the interrupt group instances (gfargrp), all cacheline aligned. This has several benefits. Firstly comes the performance benefit by having the members required by the driver's hot path re-grouped in the structure's first cache lines, whereas the unimportant members were pushed towards the end of the struct. Another benefit comes from eliminating a 24 byte memory hole that was rendering gfar_priv's 2nd cacheline useless. The default gcc layout of gfar_private leaves an implicit 24 byte hole after the errata (enum) member. This patch fixes it. The uchar bitfields were pushed towards the end of the struct as these are not run-time performance critical (used for init time operations). Because there is no other 2 byte member around to couple the uchar bitfields memeber with, we will have an addititnal 2 byte hole after the bitfields. This is unsignificant however, and it doesn't influence gfar_priv's size, because the whole structure is padded to be a 32B multiple. Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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