Re: [PATCH 15/28] netvm: network reserve infrastructure
On Wed, Feb 20, 2008 at 9:46 AM, Peter Zijlstra <[EMAIL PROTECTED]> 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
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Re: [PATCH 15/28] netvm: network reserve infrastructure
On Wed, 20 Feb 2008 15:46:25 +0100 Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> Provide the basic infrastructure to reserve and charge/account network memory.
>
> We provide the following reserve tree:
>
> 1) total network reserve
> 2)network TX reserve
> 3) protocol TX pages
> 4)network RX reserve
> 5) SKB data reserve
>
> [1] is used to make all the network reserves a single subtree, for easy
> manipulation.
>
> [2] and [4] are merely for eastetic reasons.
>
> The TX pages reserve [3] is assumed bounded by it being the upper bound of
> memory that can be used for sending pages (not quite true, but good enough)
>
> The SKB reserve [5] is an aggregate reserve, which is used to charge SKB data
> against in the fallback path.
>
> The consumers for these reserves are sockets marked with:
> SOCK_MEMALLOC
>
> Such sockets are to be used to service the VM (iow. to swap over). They
> must be handled kernel side, exposing such a socket to user-space is a BUG.
>
> +/**
> + * 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);
This looks like it should have some locking?
> + nr_socks = atomic_add_return(socks, &memalloc_socks);
> + if (!nr_socks && socks)
> + err = mem_reserve_disconnect(&net_reserve);
Or does that try to make up for it? Still looks fishy.
> + if (err)
> + mem_reserve_pages_add(&net_tx_pages, -tx_reserve_pages);
> +
> + return err;
> +}
> +
> +/**
> + * sk_set_memalloc - sets %SOCK_MEMALLOC
> + * @sk: socket to set it on
> + *
> + * Set %SOCK_MEMALLOC on a socket and increase the memalloc reserve
> + * accordingly.
> + */
> +int sk_set_memalloc(struct sock *sk)
> +{
> + int set = sock_flag(sk, SOCK_MEMALLOC);
> +#ifndef CONFIG_NETVM
> + BUG();
> +#endif
?? #error, maybe?
> + if (!set) {
> + int err = sk_adjust_memalloc(1, 0);
> + if (err)
> + return err;
> +
> + sock_set_flag(sk, SOCK_MEMALLOC);
> + sk->sk_allocation |= __GFP_MEMALLOC;
> + }
> + return !set;
> +}
> +EXPORT_SYMBOL_GPL(sk_set_memalloc);
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[PATCH 15/28] netvm: network reserve infrastructure
Provide the basic infrastructure to reserve and charge/account network memory.
We provide the following reserve tree:
1) total network reserve
2)network TX reserve
3) protocol TX pages
4)network RX reserve
5) SKB data reserve
[1] is used to make all the network reserves a single subtree, for easy
manipulation.
[2] and [4] are merely for eastetic reasons.
The TX pages reserve [3] is assumed bounded by it being the upper bound of
memory that can be used for sending pages (not quite true, but good enough)
The SKB reserve [5] is an aggregate reserve, which is used to charge SKB data
against in the fallback path.
The consumers for these reserves are sockets marked with:
SOCK_MEMALLOC
Such sockets are to be used to service the VM (iow. to swap over). They
must be handled kernel side, exposing such a socket to user-space is a BUG.
Signed-off-by: Peter Zijlstra <[EMAIL PROTECTED]>
---
include/net/sock.h | 35 +++-
net/Kconfig|3 +
net/core/sock.c| 113 +
3 files changed, 150 insertions(+), 1 deletion(-)
Index: linux-2.6/include/net/sock.h
===
--- linux-2.6.orig/include/net/sock.h
+++ linux-2.6/include/net/sock.h
@@ -51,6 +51,7 @@
#include /* struct sk_buff */
#include
#include
+#include
#include
@@ -405,6 +406,7 @@ enum sock_flags {
SOCK_RCVTSTAMPNS, /* %SO_TIMESTAMPNS setting */
SOCK_LOCALROUTE, /* route locally only, %SO_DONTROUTE setting */
SOCK_QUEUE_SHRUNK, /* write queue has been shrunk recently */
+ SOCK_MEMALLOC, /* the VM depends on us - make sure we're serviced */
};
static inline void sock_copy_flags(struct sock *nsk, struct sock *osk)
@@ -427,9 +429,40 @@ static inline int sock_flag(struct sock
return test_bit(flag, &sk->sk_flags);
}
+static inline int sk_has_memalloc(struct sock *sk)
+{
+ return sock_flag(sk, SOCK_MEMALLOC);
+}
+
+/*
+ * Guestimate the per request queue TX upper bound.
+ *
+ * Max packet size is 64k, and we need to reserve that much since the data
+ * might need to bounce it. Double it to be on the safe side.
+ */
+#define TX_RESERVE_PAGES DIV_ROUND_UP(2*65536, PAGE_SIZE)
+
+extern atomic_t memalloc_socks;
+
+extern struct mem_reserve net_rx_reserve;
+extern struct mem_reserve net_skb_reserve;
+
+static inline int sk_memalloc_socks(void)
+{
+ return atomic_read(&memalloc_socks);
+}
+
+extern int rx_emergency_get(int bytes);
+extern int rx_emergency_get_overcommit(int bytes);
+extern void rx_emergency_put(int bytes);
+
+extern int sk_adjust_memalloc(int socks, long tx_reserve_pages);
+extern int sk_set_memalloc(struct sock *sk);
+extern int sk_clear_memalloc(struct sock *sk);
+
static inline gfp_t sk_allocation(struct sock *sk, gfp_t gfp_mask)
{
- return gfp_mask;
+ return gfp_mask | (sk->sk_allocation & __GFP_MEMALLOC);
}
static inline void sk_acceptq_removed(struct sock *sk)
Index: linux-2.6/net/core/sock.c
===
--- linux-2.6.orig/net/core/sock.c
+++ linux-2.6/net/core/sock.c
@@ -112,6 +112,7 @@
#include
#include
#include
+#include
#include
#include
@@ -213,6 +214,111 @@ __u32 sysctl_rmem_default __read_mostly
/* Maximal space eaten by iovec or ancilliary data plus some space */
int sysctl_optmem_max __read_mostly = sizeof(unsigned long)*(2*UIO_MAXIOV+512);
+atomic_t memalloc_socks;
+
+static struct mem_reserve net_reserve;
+struct mem_reserve net_rx_reserve;
+EXPORT_SYMBOL_GPL(net_rx_reserve); /* modular ipv6 only */
+struct mem_reserve net_skb_reserve;
+EXPORT_SYMBOL_GPL(net_skb_reserve); /* modular ipv6 only */
+static struct mem_reserve net_tx_reserve;
+static struct mem_reserve net_tx_pages;
+
+
+/*
+ * is there room for another emergency packet?
+ */
+static int __rx_emergency_get(int bytes, bool overcommit)
+{
+ return mem_reserve_kmalloc_charge(&net_skb_reserve, bytes, overcommit);
+}
+
+int rx_emergency_get(int bytes)
+{
+ return __rx_emergency_get(bytes, false);
+}
+
+int rx_emergency_get_overcommit(int bytes)
+{
+ return __rx_emergency_get(bytes, true);
+}
+
+void rx_emergency_put(int bytes)
+{
+ mem_reserve_kmalloc_charge(&net_skb_reserve, -bytes, 0);
+}
+
+/**
+ * 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
