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

Mike Snitzer
2008-02-24T06:52:06Z

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