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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/include/net/sock.h b/include/net/sock.h
index 6ed6df149bce16598f9b6be06f2c7674de62efa5..cd6626f99ba3ea778a02538c5d79c03d28511c13 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1380,7 +1380,7 @@ 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);
-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)
@@ -1421,7 +1421,7 @@ static inline void sk_mem_reclaim(struct sock *sk)
        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)
@@ -1429,7 +1429,7 @@ static inline void sk_mem_reclaim_partial(struct sock *sk)
        if (!sk_has_account(sk))
                return;
        if (sk->sk_forward_alloc > SK_MEM_QUANTUM)
-               __sk_mem_reclaim(sk);
+               __sk_mem_reclaim(sk, sk->sk_forward_alloc - 1);
 }
 
 static inline void sk_mem_charge(struct sock *sk, int size)

diff --git a/net/core/sock.c b/net/core/sock.c
index 4ac4c13352ab7538f0ee9aad0f4c925d2fe55054..516b45c8209313f39dad99460918262d14e56659 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2095,12 +2095,13 @@ EXPORT_SYMBOL(__sk_mem_schedule);
 /**
  *     __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)
 {
-       sk_memory_allocated_sub(sk,
-                               sk->sk_forward_alloc >> SK_MEM_QUANTUM_SHIFT);
-       sk->sk_forward_alloc &= SK_MEM_QUANTUM - 1;
+       amount >>= SK_MEM_QUANTUM_SHIFT;
+       sk_memory_allocated_sub(sk, amount);
+       sk->sk_forward_alloc -= amount << SK_MEM_QUANTUM_SHIFT;
 
        if (sk_under_memory_pressure(sk) &&
            (sk_memory_allocated(sk) < sk_prot_mem_limits(sk, 0)))