Messages in this thread | | | From | Andrew Lutomirski <> | Date | Mon, 21 Apr 2014 18:28:12 -0700 | Subject | Re: [PATCH] x86-64: espfix for 64-bit mode *PROTOTYPE* |
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On Mon, Apr 21, 2014 at 6:14 PM, H. Peter Anvin <hpa@zytor.com> wrote: > I wanted to avoid the "another cpu made this allocation, now I have to free" crap, but I also didn't want to grab the lock if there was no work needed.
I guess you also want to avoid bouncing all these cachelines around on boot on bit multicore machines.
I'd advocate using the bitmap approach or simplifying the existing code. For example:
+ for (n = 0; n < ESPFIX_PUD_CLONES; n++) { + pud = ACCESS_ONCE(pud_p[n]); + if (!pud_present(pud)) + return false; + }
I don't see why that needs to be a loop. How can one clone exist but not the others?
--Andy
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