Messages in this thread | | | From | Namhyung Kim <> | Subject | Re: [PATCH 06/14] perf tools: Cache dso data file descriptor | Date | Thu, 29 May 2014 09:02:36 +0900 |
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On Tue, 27 May 2014 09:37:38 +0200, Jiri Olsa wrote: > On Tue, May 27, 2014 at 10:05:28AM +0900, Namhyung Kim wrote: >> Hi Jiri, >> >> On Thu, 15 May 2014 19:23:27 +0200, Jiri Olsa wrote: >> >> [SNIP] >> > +static void data_close(void) >> > +{ >> > + bool cache_fd = may_cache_fd(); >> > + >> > + if (!cache_fd) >> > + close_first_dso(); >> > +} >> >> Why do you do this at close()? As long as there's no attempt to open a >> new file, we can keep existing fd, no? > > so the way it works now is: > > - we keep up to the 'RLIMIT_NOFILE / 2' of open dso objects > - if we try to open dso and it fails, because we are out of > file descriptors, we close dso objects and try to reopen > (check do_open function) > - when we close the dso object we check if number of opened > dso objects is below 'RLIMIT_NOFILE / 2'.. if it is, we keep > the dso opened, if not we close first dso in the list > > util/dso.h tries to describe that
Yes, I know. But my question is why do this at close()? Isn't it sufficient to check the file limit at open() and close previous one if necessary?
> >> >> > + >> > +void dso__data_close(struct dso *dso) >> > +{ >> > + if (dso->data.fd >= 0) >> > + data_close(); >> > +} >> >> Hmm.. it's confusing dso__data_close(dso) closes an other dso rather >> than the given dso. And this dso__data_close() is not paired with any >> _open() also these close calls make me confusing which one to use. ;-p > > thats due to the caching.. as explained above > > About the pairing.. originally the interface was only dso__data_fd > that opened and returned fd, which the caller needed to close. > > I added dso__data_close so we could keep track of file descriptors. > > I could add dso__data_open I guess, but it is dso__data_fd which is > needed for elf interface anyway.
I'd rather suggest dropping the open/close idiom for this case since it's confusing. What about get/put or get_fd/put_fd?
Thanks, Namhyung
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