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Date: Wed, 07 May 2014 12:05:58 +0900 From: Namhyung Kim <namhyung@...nel.org> To: Don Zickus <dzickus@...hat.com> Cc: Arnaldo Carvalho de Melo <acme@...nel.org>, Jiri Olsa <jolsa@...hat.com>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Ingo Molnar <mingo@...nel.org>, Paul Mackerras <paulus@...ba.org>, Namhyung Kim <namhyung.kim@....com>, LKML <linux-kernel@...r.kernel.org>, David Ahern <dsahern@...il.com>, Andi Kleen <andi@...stfloor.org> Subject: Re: [PATCHSET 00/17] perf report: Add -F option for specifying output fields (v4) Hi Don, On Wed, 30 Apr 2014 09:35:55 -0400, Don Zickus wrote: > On Wed, Apr 30, 2014 at 08:38:10AM +0900, Namhyung Kim wrote: >> Hi Don, >> >> On Tue, 29 Apr 2014 13:27:35 -0400, Don Zickus wrote: >> > On Tue, Apr 29, 2014 at 10:13:35AM +0900, Namhyung Kim wrote: >> >> > /* >> >> > * Addresses with no major/minor numbers are assumed to be >> >> > * anonymous in userspace. Sort those on pid then address. >> >> > * >> >> > * The kernel and non-zero major/minor mapped areas are >> >> > * assumed to be unity mapped. Sort those on address. >> >> > */ >> >> > >> >> > if ((left->cpumode != PERF_RECORD_MISC_KERNEL) && >> >> > !l_map->maj && !l_map->min && !l_map->ino && >> >> > !l_map->ino_generation) { >> >> > /* userspace anonymous */ >> >> > >> >> > if (left->thread->pid_ > right->thread->pid_) return -1; >> >> > if (left->thread->pid_ < right->thread->pid_) return 1; >> >> >> >> Isn't it necessary to check whether the address is in a same map in case >> >> of anon pages? I mean the daddr.al_addr is a map-relative offset so it >> >> might have same value for different maps. >> > >> > That's why I sort on pids here. Because the anon address might have the >> > same value for different maps. The thought was to group all the pid >> > addresses together to keep things seperated. >> > >> > Do you see a different way to solve the problem? I am not sure al_addr >> > vs. addr will make much difference here. >> >> I'm not saying to get rid of the pid check, I'm saying that it might >> need to add another check for maps (i.e. start address) as there might >> be many maps in a single address space. > > Hmm, I guess I would need to see an example. While I agree there might be > many maps in a single address space (/proc/<pid>/maps demonstrates that), > I understood them to map to a unique location (ie no overlap) unless they > are shared. > > I am willing to believe I missed scenario when sorting, I just can't think > of it (so I wouldn't know how to fix it). That's why I was looking for an > example to make it more obvious to me. Sorry for being slow.. I'm also sorry for being late. Looking at the code, it seems to use identity__map_ip() for anon maps so my concern is bogus. Please just forget about it and keep going. Sorry for interrupting your work.. Thanks, Namhyung -- 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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