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 <a.p.zijlstra@chello.nl>
---
include/net/sock.h | 43 ++++++++++++++++++++-
net/Kconfig | 3 +
net/core/sock.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 152 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
@@ -50,6 +50,7 @@
#include <linux/skbuff.h> /* struct sk_buff */
#include <linux/mm.h>
#include <linux/security.h>
+#include <linux/reserve.h>
#include <linux/filter.h>
@@ -413,6 +414,7 @@ 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)
@@ -435,9 +437,48 @@ static inline int sock_flag(struct sock
return test_bit(flag, &sk->sk_flags);
}
+static inline int ...
