On 5/27/10, Erik Faye-Lund <kusmabite@xxxxxxxxxxxxxx> wrote: > On Thu, May 27, 2010 at 1:39 PM, Marko Kreen <markokr@xxxxxxxxx> wrote: > > On 5/27/10, Erik Faye-Lund <kusmabite@xxxxxxxxxxxxxx> wrote: > >> On Thu, May 27, 2010 at 12:10 PM, Jonathan Nieder <jrnieder@xxxxxxxxx> wrote: > >> > Implement the subset of poll() semantics needed by git in terms of > >> > select(), for use by the Interix port. Inspired by commit 6ed807f > >> > (Windows: A rudimentary poll() emulation, 2007-12-01). > >> > > >> > >> > >> A possible problem with this approach is that the maximum number of > >> file descriptors poll can handle limited by RLIMIT_NOFILE, whereas the > >> maximum number of file descriptors select can handle is limited by > >> FD_SETSIZE. > >> > >> I don't think this is a big problem in reality, though - both values > >> seem to be pretty high in most implementations. And IIRC git-daemon is > >> the only one who needs more than 2, and it doesn't even check > >> RLIMIT_NOFILE. > >> > >> If we decide to go this route, perhaps it'd make sense to change to > >> this code for Windows also? Our Windows-implementation of poll() has > >> some annoying limitations... > > > > Example of poll() compat without FD_SETSIZE limit: > > > > http://github.com/markokr/plproxy-dev/blob/master/src/poll_compat.c > > > > > How does this code convince FD_SET() that the buffer has increased? It > looks to me like it depends on a specific FD_SET() implementation... > For instance, Windows' FD_SET() implementation is like this: > > #define FD_SET(fd, set) do { \ > if (((fd_set FAR *)(set))->fd_count < FD_SETSIZE) \ > ((fd_set FAR *)(set))->fd_array[((fd_set FAR > *)(set))->fd_count++]=(fd);\ > } while(0) > > ...so unless another set is passed in, it won't add any more fds once > fd_count reaches FD_SETSIZE. > > Also, FD_SETSIZE is 64 on Windows. IIRC it's 1024 on Linux, so it is > much more likely that we encounter this issue on Windows than on > Linux, at least ;) Hm, good catch. Seems such compat poll() cannot be done without OS-specific hacks. Do you know perhaps what other OS-es have non-bitmap fd_set? -- marko -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html