Re: an experiment in pipe bandwidth improvement

Andrea Arcangeli (andrea@suse.de)
Tue, 11 Jan 2000 01:16:59 +0100 (CET)


On Mon, 10 Jan 2000, Zack Weinberg wrote:

>On Mon, Jan 10, 2000 at 08:49:10PM +0100, Andrea Arcangeli wrote:
>> On Sun, 9 Jan 2000, Zack Weinberg wrote:
>>
>> >+ && !(new = __get_free_pages(GFP_USER, order)))
>>
>> mm fragmentation and the VM not good in handling a fragmented mm is going
>> to hurt you.
>
>I was under the impression __get_free_pages allocated physically contiguous
>memory.

Your impression is correct and that's the source of the mm fragmentation
trouble.

>Do you know how to limit the size of AF_UNIX packets? I would like to try

You set it by hand: set sock opt SO_SNDBUF plus sysclt_*mem_max.

For stream AF_UNIX sockets you fallback to 1 page if the allocation fails
so you don't know. For dgram sockets you'll have to do the full allocation
in one packet or you'll wait.

Andrea

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/