Messages in this thread | | | Date | Wed, 17 Dec 2008 15:52:39 +0100 | From | Jiri Pirko <> | Subject | Re: [PATCH, RESEND2] getrusage: fill ru_maxrss value |
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On Wed, 17 Dec 2008 21:03:27 +0900 (JST) KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> > > > This patch makes ->ru_maxrss value in struct rusage filled accordingly to > > > > rss hiwater mark. This struct is filled as a parameter to > > > > getrusage syscall. ->ru_maxrss value is set to pages which might be correct > > > > as "time" application converts it to KBs. > > > > > > Why? > > > if kernel convert to KB, glibc don't need any change. > > Where exactly glibc is working with this as KBs? I can't find that place. > > > > I looked into sources of time util and maxrss is showed this way: > > fprintf (fp, "%lu", ptok ((UL) resp->ru.ru_maxrss)); > > ptok() actually does pages_to_KB conversion. If we convert to KB in > > kernel, this code must be changed. > > Ah, you talked about /usr/bin/time? sorry, I misunderstood a bit. > Why time need number of pages? > > In general, getrusage()::ru_maxrss is bsd compatibility feature. > as far as possible, the same syscall spec is better. > and bsd use KB unit. Oh you are right. Now I searched it in FreeBSD kernel. They goes like this: rss = pgtok(vmspace_resident_count(vm)); if (ru->ru_maxrss < rss) ru->ru_maxrss = rss;
Seems pretty reasonable to stick with the same behavior. Then I really do not understand why /usr/bin/time does the conversion. FreeBSD /usr/bin/time is very different and much simpler and (of course) does not do this conversion.
So I suggest to change the patch to fill KB instead of pages and change /usr/bin/time to not do the conversion. What do you think? > > if time command has reasonable reason, I can agree current design. > but is there? > > >
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