On 06/03/2015 06:38 PM, Josh Triplett wrote: > On Wed, Jun 03, 2015 at 03:58:50PM +0200, Denys Vlasenko wrote: >> Really swap arguments #4 and #5 in stub32_clone instead of "optimizing" >> it into a move. >> >> Yes, tls_val is currently unused. Yes, on some CPUs XCHG is a little bit >> more expensive than MOV. But a cycle or two on an expensive syscall like >> clone() is way below noise floor, and this optimization is simply not worth >> the obfuscation of logic. > [...] >> This is a resend. >> >> There was a patch by Josh Triplett >> "x86: Opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit" >> sent on May 11, >> which does the same thing as part of a bigger cleanup. >> He was supportive of this patch because of comments. >> He will simply have to drop one hunk from his patch. > > Strictly speaking, nothing needs this until clone starts paying > attention to its tls argument, which only happens in my cleanup series > that includes this change. So what's the purpose of driving this patch > separately?
You wanted my comments in this patch to go in: On 04/22/2015 07:10 PM, Josh Triplett wrote: > I do think my two-patch HAVE_COPY_THREAD_TLS series should go in fixing > this, but I'd like to see the final version of Denys' comment added on > top of it (with an update to the type and name of the tls argument to > match the changes to sys_clone). If your patch will go in first, I'll send a patch adding only the comment. Since for now your patch did not make it yet, I'm submitting a patch which adds both a comment and the insn change. -- vda -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
