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Message-Id: <20111128115541.bc8f2ffa.kamezawa.hiroyu@jp.fujitsu.com>
Date: Mon, 28 Nov 2011 11:55:41 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To: Glauber Costa <glommer@...allels.com>
Cc: linux-kernel@...r.kernel.org, lizf@...fujitsu.com,
ebiederm@...ssion.com, davem@...emloft.net, paul@...lmenage.org,
gthelen@...gle.com, netdev@...r.kernel.org, linux-mm@...ck.org,
kirill@...temov.name, avagin@...allels.com, devel@...nvz.org,
eric.dumazet@...il.com, cgroups@...r.kernel.org
Subject: Re: [PATCH v6 02/10] foundations of per-cgroup memory pressure
controlling.
On Fri, 25 Nov 2011 15:38:08 -0200
Glauber Costa <glommer@...allels.com> wrote:
> This patch replaces all uses of struct sock fields' memory_pressure,
> memory_allocated, sockets_allocated, and sysctl_mem to acessor
> macros. Those macros can either receive a socket argument, or a mem_cgroup
> argument, depending on the context they live in.
>
> Since we're only doing a macro wrapping here, no performance impact at all is
> expected in the case where we don't have cgroups disabled.
>
> Signed-off-by: Glauber Costa <glommer@...allels.com>
> CC: David S. Miller <davem@...emloft.net>
> CC: Hiroyouki Kamezawa <kamezawa.hiroyu@...fujitsu.com>
> CC: Eric W. Biederman <ebiederm@...ssion.com>
> CC: Eric Dumazet <eric.dumazet@...il.com>
I have some comments on the style. Maybe a nitpick but many patches were
sent for fixing conding style in memcg recently.
+static inline int *sk_memory_pressure(const struct sock *sk)
+{
+ return sk->sk_prot->memory_pressure;
+}
+
+static inline long sk_prot_mem(const struct sock *sk, int index)
+{
+ long *prot = sk->sk_prot->sysctl_mem;
+ return prot[index];
+}
+
I don't think sk_prot_mem() is an easy to undestand name.
sk_prot_memory_limit() ?
> +static inline int
> +kcg_sockets_allocated_sum_positive(struct proto *prot, struct mem_cgroup *cg)
> +{
> + return percpu_counter_sum_positive(prot->sockets_allocated);
> +}
> +
> +static inline long
> +kcg_memory_allocated(struct proto *prot, struct mem_cgroup *cg)
> +{
> + return atomic_long_read(prot->memory_allocated);
> +}
>
I don't like 'kcg'. What it means ?
memory_cgrou_prot_socekts_allocated() ? and
memory_cgroup_prot_memory_allocated() ?
And the variable for memory cgroup should be 'memcg'.
http://www.spinics.net/lists/linux-mm/msg26781.html
So, please rename.
> #ifdef CONFIG_PROC_FS
> /* Called with local bh disabled */
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index e147f42..ccaa3b6 100644
<snip>
seq_printf(seq, "RAW: inuse %d\n",
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 34f5db1..89a2bfe 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -319,9 +319,11 @@ EXPORT_SYMBOL(tcp_memory_pressure);
>
> void tcp_enter_memory_pressure(struct sock *sk)
> {
> - if (!tcp_memory_pressure) {
> + int *memory_pressure = sk_memory_pressure(sk);
> +
Don't you need !memory_pressure check here ?
Hmm, can this function be
+static inline int *sk_memory_pressure(const struct sock *sk)
+{
+ return sk->sk_prot->memory_pressure;
+}
as
static inline bool sk_under_prot_memory_pressure(const struct sock *sk)
{
if (sk->sk_prot->memory_pressure &&
*sk->sk_prot->memory_pressure)
return true;
return false;
}
and have sk_set/unset_prot_memory_pressure(), ?
> + if (!*memory_pressure) {
> NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMEMORYPRESSURES);
> - tcp_memory_pressure = 1;
> + *memory_pressure = 1;
> }
> }
> EXPORT_SYMBOL(tcp_enter_memory_pressure);
> diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
> index 52b5c2d..3df862d 100644
> --- a/net/ipv4/tcp_input.c
> +++ b/net/ipv4/tcp_input.c
> @@ -322,7 +322,7 @@ static void tcp_grow_window(struct sock *sk, const struct sk_buff *skb)
> /* Check #1 */
> if (tp->rcv_ssthresh < tp->window_clamp &&
> (int)tp->rcv_ssthresh < tcp_space(sk) &&
> - !tcp_memory_pressure) {
> + !sk_memory_pressure(sk)) {
Don't you need to check !*sk_memory_pressure(sk) ?
> int incr;
>
> /* Check #2. Increase window, if skb with such overhead
> @@ -411,8 +411,8 @@ static void tcp_clamp_window(struct sock *sk)
>
> if (sk->sk_rcvbuf < sysctl_tcp_rmem[2] &&
> !(sk->sk_userlocks & SOCK_RCVBUF_LOCK) &&
> - !tcp_memory_pressure &&
> - atomic_long_read(&tcp_memory_allocated) < sysctl_tcp_mem[0]) {
> + !sk_memory_pressure(sk) &&
> + sk_memory_allocated(sk) < sk_prot_mem(sk, 0)) {
> sk->sk_rcvbuf = min(atomic_read(&sk->sk_rmem_alloc),
> sysctl_tcp_rmem[2]);
> }
> @@ -4864,7 +4864,7 @@ static int tcp_prune_queue(struct sock *sk)
>
> if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)
> tcp_clamp_window(sk);
> - else if (tcp_memory_pressure)
> + else if (sk_memory_pressure(sk))
> tp->rcv_ssthresh = min(tp->rcv_ssthresh, 4U * tp->advmss);
Ditto.
>
> tcp_collapse_ofo_queue(sk);
> @@ -4930,11 +4930,11 @@ static int tcp_should_expand_sndbuf(const struct sock *sk)
> return 0;
>
> /* If we are under global TCP memory pressure, do not expand. */
> - if (tcp_memory_pressure)
> + if (sk_memory_pressure(sk))
> return 0;
again.
Thanks,
-Kame
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