net: set SK_MEM_QUANTUM to 4096
Systems with large pages (64KB pages for example) do not always have huge quantity of memory. A big SK_MEM_QUANTUM value leads to fewer interactions with the global counters (like tcp_memory_allocated) but might trigger memory pressure much faster, giving suboptimal TCP performance since windows are lowered to ridiculous values. Note that sysctl_mem units being in pages and in ABI, we also need to change sk_prot_mem_limits() accordingly. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -1162,11 +1162,6 @@ static inline void sk_enter_memory_pressure(struct sock *sk)
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sk->sk_prot->enter_memory_pressure(sk);
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}
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static inline long sk_prot_mem_limits(const struct sock *sk, int index)
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{
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return sk->sk_prot->sysctl_mem[index];
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}
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static inline long
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sk_memory_allocated(const struct sock *sk)
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{
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@ -1281,11 +1276,27 @@ int __sk_mem_schedule(struct sock *sk, int size, int kind);
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void __sk_mem_reduce_allocated(struct sock *sk, int amount);
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void __sk_mem_reclaim(struct sock *sk, int amount);
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#define SK_MEM_QUANTUM ((int)PAGE_SIZE)
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/* We used to have PAGE_SIZE here, but systems with 64KB pages
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* do not necessarily have 16x time more memory than 4KB ones.
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*/
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#define SK_MEM_QUANTUM 4096
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#define SK_MEM_QUANTUM_SHIFT ilog2(SK_MEM_QUANTUM)
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#define SK_MEM_SEND 0
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#define SK_MEM_RECV 1
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/* sysctl_mem values are in pages, we convert them in SK_MEM_QUANTUM units */
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static inline long sk_prot_mem_limits(const struct sock *sk, int index)
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{
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long val = sk->sk_prot->sysctl_mem[index];
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#if PAGE_SIZE > SK_MEM_QUANTUM
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val <<= PAGE_SHIFT - SK_MEM_QUANTUM_SHIFT;
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#elif PAGE_SIZE < SK_MEM_QUANTUM
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val >>= SK_MEM_QUANTUM_SHIFT - PAGE_SHIFT;
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#endif
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return val;
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}
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static inline int sk_mem_pages(int amt)
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{
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return (amt + SK_MEM_QUANTUM - 1) >> SK_MEM_QUANTUM_SHIFT;
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