[PATCH 17/29] netvm: prevent a TCP specific deadlock
From: Peter Zijlstra <hidden>
Date: 2007-02-21 15:34:41
Also in:
linux-mm, lkml
It could happen that all !SOCK_VMIO sockets have buffered so much data that we're over the global rmem limit. This will prevent SOCK_VMIO buffers from receiving data, which will prevent userspace from running, which is needed to reduce the buffered data. Signed-off-by: Peter Zijlstra <redacted> --- include/net/sock.h | 7 ++++--- net/core/stream.c | 5 +++-- net/ipv4/tcp_ipv4.c | 8 ++++++++ net/ipv6/tcp_ipv6.c | 8 ++++++++ 4 files changed, 23 insertions(+), 5 deletions(-) Index: linux-2.6-git/include/net/sock.h ===================================================================
--- linux-2.6-git.orig/include/net/sock.h 2007-02-14 12:09:05.000000000 +0100
+++ linux-2.6-git/include/net/sock.h 2007-02-14 12:09:21.000000000 +0100@@ -730,7 +730,8 @@ static inline struct inode *SOCK_INODE(s } extern void __sk_stream_mem_reclaim(struct sock *sk); -extern int sk_stream_mem_schedule(struct sock *sk, int size, int kind); +extern int sk_stream_mem_schedule(struct sock *sk, struct sk_buff *skb, + int size, int kind); #define SK_STREAM_MEM_QUANTUM ((int)PAGE_SIZE)
@@ -757,13 +758,13 @@ static inline void sk_stream_writequeue_ static inline int sk_stream_rmem_schedule(struct sock *sk, struct sk_buff *skb) { return (int)skb->truesize <= sk->sk_forward_alloc || - sk_stream_mem_schedule(sk, skb->truesize, 1); + sk_stream_mem_schedule(sk, skb, skb->truesize, 1); } static inline int sk_stream_wmem_schedule(struct sock *sk, int size) { return size <= sk->sk_forward_alloc || - sk_stream_mem_schedule(sk, size, 0); + sk_stream_mem_schedule(sk, NULL, size, 0); } /* Used by processes to "lock" a socket state, so that
Index: linux-2.6-git/net/core/stream.c ===================================================================
--- linux-2.6-git.orig/net/core/stream.c 2007-02-14 12:09:05.000000000 +0100
+++ linux-2.6-git/net/core/stream.c 2007-02-14 12:09:21.000000000 +0100@@ -207,7 +207,7 @@ void __sk_stream_mem_reclaim(struct sock EXPORT_SYMBOL(__sk_stream_mem_reclaim); -int sk_stream_mem_schedule(struct sock *sk, int size, int kind) +int sk_stream_mem_schedule(struct sock *sk, struct sk_buff *skb, int size, int kind) { int amt = sk_stream_pages(size);
@@ -224,7 +224,8 @@ int sk_stream_mem_schedule(struct sock * /* Over hard limit. */ if (atomic_read(sk->sk_prot->memory_allocated) > sk->sk_prot->sysctl_mem[2]) { sk->sk_prot->enter_memory_pressure(); - goto suppress_allocation; + if (!skb || (skb && !skb_emergency(skb))) + goto suppress_allocation; } /* Under pressure. */
--