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Message-ID: <20151007150509.GA23710@nazgul.tnic> Date: Wed, 7 Oct 2015 17:05:09 +0200 From: Borislav Petkov <bp@...en8.de> To: Brian Gerst <brgerst@...il.com> Cc: Andy Lutomirski <luto@...nel.org>, the arch/x86 maintainers <x86@...nel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, Denys Vlasenko <dvlasenk@...hat.com>, Linus Torvalds <torvalds@...ux-foundation.org> Subject: Re: [PATCH v2 05/36] x86/entry/64/compat: Fix SYSENTER's NT flag before user memory access On Wed, Oct 07, 2015 at 10:33:10AM -0400, Brian Gerst wrote: > This is an optimization, since NT is unlikely to be set. The forward > branch is usually predicted as not taken, and it keeps these rarely > used instructions out of the hot cache. Ah, slick. Because branch predictors mark new branches as not taken and this particular one will remain non-taken in the majority of the cases. I think this warrants a mention in the comment above it though... -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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