Re: [PATCH 15/28] netvm: network reserve infrastructure

["Mike Snitzer" <snitzer@gmail.com>]

On Wed, Feb 20, 2008 at 9:46 AM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> Provide the basic infrastructure to reserve and charge/account network memory.
...

>  Index: linux-2.6/net/core/sock.c
>  ===================================================================
>  --- linux-2.6.orig/net/core/sock.c
>  +++ linux-2.6/net/core/sock.c
...
>  +/**
>  + *     sk_adjust_memalloc - adjust the global memalloc reserve for critical RX
>  + *     @socks: number of new %SOCK_MEMALLOC sockets
>  + *     @tx_resserve_pages: number of pages to (un)reserve for TX
>  + *
>  + *     This function adjusts the memalloc reserve based on system demand.
>  + *     The RX reserve is a limit, and only added once, not for each socket.
>  + *
>  + *     NOTE:
>  + *        @tx_reserve_pages is an upper-bound of memory used for TX hence
>  + *        we need not account the pages like we do for RX pages.
>  + */
>  +int sk_adjust_memalloc(int socks, long tx_reserve_pages)
>  +{
>  +       int nr_socks;
>  +       int err;
>  +
>  +       err = mem_reserve_pages_add(&net_tx_pages, tx_reserve_pages);
>  +       if (err)
>  +               return err;
>  +
>  +       nr_socks = atomic_read(&memalloc_socks);
>  +       if (!nr_socks && socks > 0)
>  +               err = mem_reserve_connect(&net_reserve, &mem_reserve_root);
>  +       nr_socks = atomic_add_return(socks, &memalloc_socks);
>  +       if (!nr_socks && socks)
>  +               err = mem_reserve_disconnect(&net_reserve);
>  +
>  +       if (err)
>  +               mem_reserve_pages_add(&net_tx_pages, -tx_reserve_pages);
>  +
>  +       return err;
>  +}

EXPORT_SYMBOL_GPL(sk_adjust_memalloc); is needed here to build sunrpc
as a module.

Mike