Messages in this thread | | | Date | Tue, 27 May 2014 09:37:38 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 06/14] perf tools: Cache dso data file descriptor |
| |
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
> > > + > > +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.
thanks, jirka
| |