net: fix sk_mem_reclaim_partial()

commit 1a24e04e4b50939daa3041682b38b82c896ca438 upstream.

sk_mem_reclaim_partial() goal is to ensure each socket has
one SK_MEM_QUANTUM forward allocation. This is needed both for
performance and better handling of memory pressure situations in
follow up patches.

SK_MEM_QUANTUM is currently a page, but might be reduced to 4096 bytes
as some arches have 64KB pages.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
 - Keep using atomic_long_sub() directly, not sk_memory_allocated_sub()
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/include/net/sock.h b/include/net/sock.h
index 8ae4a48..b0da43d 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -961,7 +961,7 @@ static inline struct inode *SOCK_INODE(struct socket *socket)
  * Functions for memory accounting
  */
 extern int __sk_mem_schedule(struct sock *sk, int size, int kind);
  * Functions for memory accounting
  */
 extern int __sk_mem_schedule(struct sock *sk, int size, int kind);

-extern void __sk_mem_reclaim(struct sock *sk);
+void __sk_mem_reclaim(struct sock *sk, int amount);

 
 #define SK_MEM_QUANTUM ((int)PAGE_SIZE)
 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
 
 #define SK_MEM_QUANTUM ((int)PAGE_SIZE)
 #define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)


@@ -1000,7 +1000,7 @@ static inline void sk_mem_reclaim(struct sock *sk)
        if (!sk_has_account(sk))
                return;
        if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)
        if (!sk_has_account(sk))
                return;
        if (sk->sk_forward_alloc >= SK_MEM_QUANTUM)

-               __sk_mem_reclaim(sk);
+               __sk_mem_reclaim(sk, sk->sk_forward_alloc);

 }
 
 static inline void sk_mem_reclaim_partial(struct sock *sk)
 }
 
 static inline void sk_mem_reclaim_partial(struct sock *sk)


@@ -1008,7 +1008,7 @@ static inline void sk_mem_reclaim_partial(struct sock *sk)
        if (!sk_has_account(sk))
                return;
        if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
        if (!sk_has_account(sk))
                return;
        if (sk->sk_forward_alloc > SK_MEM_QUANTUM)

-               __sk_mem_reclaim(sk);
+               __sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);

 }
 
 static inline void sk_mem_charge(struct sock *sk, int size)
 }
 
 static inline void sk_mem_charge(struct sock *sk, int size)

diff --git a/net/core/sock.c b/net/core/sock.c
index 54a21d4..b8f4f35 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1750,14 +1750,15 @@ EXPORT_SYMBOL(__sk_mem_schedule);
 /**
  *     __sk_reclaim - reclaim memory_allocated
  *     @sk: socket
 /**
  *     __sk_reclaim - reclaim memory_allocated
  *     @sk: socket

+ *     @amount: number of bytes (rounded down to a SK_MEM_QUANTUM multiple)

  */
  */

-void __sk_mem_reclaim(struct sock *sk)
+void __sk_mem_reclaim(struct sock *sk, int amount)

 {
        struct proto *prot = sk->sk_prot;
 
 {
        struct proto *prot = sk->sk_prot;
 

-       atomic_long_sub(sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT,
-                  prot->memory_allocated);
-       sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;
+       amount >>= SK_MEM_QUANTUM_SHIFT;
+       atomic_long_sub(amount, prot->memory_allocated);
+       sk->sk_forward_alloc -= amount << SK_MEM_QUANTUM_SHIFT;

 
        if (prot->memory_pressure && *prot->memory_pressure &&
            (atomic_long_read(prot->memory_allocated) < prot->sysctl_mem[0]))
 
        if (prot->memory_pressure && *prot->memory_pressure &&
            (atomic_long_read(prot->memory_allocated) < prot->sysctl_mem[0]))