On Jun 3, 2009, at 1:06 PM, Robert Watson wrote: > > Is there a reason not just to use __aligned(64) or the like on the > first entry of the MD PCPU structure for sun4v to avoid future MI > pcpu changes from causing similar discomfort for the MD pcpu parts? > Also, do we know why these alignment/sizing requirements exist for > struct pcpu on sun4v but not other platforms? If this is about > packing pcpu structures into properly aligned cache lines, again > __aligned() might be the right approach to take... Adding __aligned(xx) doesn't make it aligned. For example, malloc(3) only aligns at 16-byte boundaries, so any user-space structure that has __aligned(x>16) must manually make sure that this is actually the case by over-allocating and then adjusting the pointer to an x>16 aligned address. Likewise for the kernel, though it's easier in the kernel to get something that's page-aligned... FYI, -- Marcel Moolenaar xcllnt_at_mac.comReceived on Wed Jun 03 2009 - 21:14:40 UTC
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