* Eric Dumazet <[EMAIL PROTECTED]> wrote: > > speedup: i suggested O_ANY 6 years ago as a speedup to Apache - > > non-linear fds are cheaper to allocate/map: > > > > http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg23820.html > > > > (i definitely remember having written code for that too, but i > > cannot find that in the archives. hm.) In theory we could avoid > > _all_ fd-bitmap overhead as well and use a per-process list/pool of > > struct file buffers plus a maximum-fd field as the 'non-linear fd > > allocator' (at the price of only deallocating them at process exit > > time). > > Only very few apps need to open more than 100.000 files.
yes. I did not list it as a primary reason for private fds, it's just a nice side-effect. As long as the other apps are not hurt, i see no problem in improving the >100K open files case. > As these files are likely sockets, O_ANY is not a solution. why not? It would be a natural thing to extend sys_socket() with a 'flags' parameter and pass in O_ANY (along with any other possible fd parameter like O_NDELAY, which could be inherited over connect()). > A trick is to try to keep first 64 handles freed, so that kernel wont > consume too much cpu time and cache in get_unused_fd() > > http://lkml.org/lkml/2005/9/15/307 this is basically a user-space front-end cache to fd allocation - which duplicates data needlessly. I dont see any problem with doing this in the kernel. (Also, obviously 'first 64 handles' could easily break with certain types of apps so glibc cannot do this.) Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
