linux-toradex.git/net/core/sock.c, branch v4.1.1

net: don't wait for order-3 page allocation

2015-06-12T00:33:44+00:00

We saw excessive direct memory compaction triggered by skb_page_frag_refill.
This causes performance issues and add latency. Commit 5640f7685831e0
introduces the order-3 allocation. According to the changelog, the order-3
allocation isn't a must-have but to improve performance. But direct memory
compaction has high overhead. The benefit of order-3 allocation can't
compensate the overhead of direct memory compaction.

This patch makes the order-3 page allocation atomic. If there is no memory
pressure and memory isn't fragmented, the alloction will still success, so we
don't sacrifice the order-3 benefit here. If the atomic allocation fails,
direct memory compaction will not be triggered, skb_page_frag_refill will
fallback to order-0 immediately, hence the direct memory compaction overhead is
avoided. In the allocation failure case, kswapd is waken up and doing
compaction, so chances are allocation could success next time.

alloc_skb_with_frags is the same.

The mellanox driver does similar thing, if this is accepted, we must fix
the driver too.

V3: fix the same issue in alloc_skb_with_frags as pointed out by Eric
V2: make the changelog clearer

Cc: Eric Dumazet 
Cc: Chris Mason 
Cc: Debabrata Banerjee 
Signed-off-by: Shaohua Li 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net, swap: Remove a warning and clarify why sk_mem_reclaim is required when deactivating swap

2015-06-11T06:02:31+00:00

Jeff Layton reported the following;

 [   74.232485] ------------[ cut here ]------------
 [   74.233354] WARNING: CPU: 2 PID: 754 at net/core/sock.c:364 sk_clear_memalloc+0x51/0x80()
 [   74.234790] Modules linked in: cts rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache xfs libcrc32c snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device nfsd snd_pcm snd_timer snd e1000 ppdev parport_pc joydev parport pvpanic soundcore floppy serio_raw i2c_piix4 pcspkr nfs_acl lockd virtio_balloon acpi_cpufreq auth_rpcgss grace sunrpc qxl drm_kms_helper ttm drm virtio_console virtio_blk virtio_pci ata_generic virtio_ring pata_acpi virtio
 [   74.243599] CPU: 2 PID: 754 Comm: swapoff Not tainted 4.1.0-rc6+ #5
 [   74.244635] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 [   74.245546]  0000000000000000 0000000079e69e31 ffff8800d066bde8 ffffffff8179263d
 [   74.246786]  0000000000000000 0000000000000000 ffff8800d066be28 ffffffff8109e6fa
 [   74.248175]  0000000000000000 ffff880118d48000 ffff8800d58f5c08 ffff880036e380a8
 [   74.249483] Call Trace:
 [   74.249872]  [] dump_stack+0x45/0x57
 [   74.250703]  [] warn_slowpath_common+0x8a/0xc0
 [   74.251655]  [] warn_slowpath_null+0x1a/0x20
 [   74.252585]  [] sk_clear_memalloc+0x51/0x80
 [   74.253519]  [] xs_disable_swap+0x42/0x80 [sunrpc]
 [   74.254537]  [] rpc_clnt_swap_deactivate+0x7e/0xc0 [sunrpc]
 [   74.255610]  [] nfs_swap_deactivate+0x27/0x30 [nfs]
 [   74.256582]  [] destroy_swap_extents+0x74/0x80
 [   74.257496]  [] SyS_swapoff+0x222/0x5c0
 [   74.258318]  [] ? syscall_trace_leave+0xc7/0x140
 [   74.259253]  [] system_call_fastpath+0x12/0x71
 [   74.260158] ---[ end trace 2530722966429f10 ]---

The warning in question was unnecessary but with Jeff's series the rules
are also clearer.  This patch removes the warning and updates the comment
to explain why sk_mem_reclaim() may still be called.

[jlayton: remove if (sk->sk_forward_alloc) conditional. As Leon
          points out that it's not needed.]

Cc: Leon Romanovsky 
Signed-off-by: Mel Gorman 
Signed-off-by: Jeff Layton 
Signed-off-by: David S. Miller

Revert "net: kernel socket should be released in init_net namespace"

2015-05-04T04:13:16+00:00

This reverts commit c243d7e20996254f89c28d4838b5feca735c030d.

That patch is solving a non-existant problem while creating a
real problem.  Just because a socket is allocated in the init
name space doesn't mean that it gets hashed in the init name space.

When we unhash it the name space must be the same as the one
we had when we hashed it.  So this patch is completely bogus
and causes socket leaks.

Reported-by: Andrey Wagin 
Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller

tcp: do not cache align timewait sockets

2015-04-13T01:16:05+00:00

With recent adoption of skc_cookie in struct sock_common,
struct tcp_timewait_sock size increased from 192 to 200 bytes
on 64bit arches. SLAB rounds then to 256 bytes.

It is time to drop SLAB_HWCACHE_ALIGN constraint for twsk_slab.

This saves about 12 MB of memory on typical configuration reaching
262144 timewait sockets, and has no noticeable impact on performance.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2015-04-07T02:34:15+00:00

Conflicts:
	drivers/net/ethernet/mellanox/mlx4/cmd.c
	net/core/fib_rules.c
	net/ipv4/fib_frontend.c

The fib_rules.c and fib_frontend.c conflicts were locking adjustments
in 'net' overlapping addition and removal of code in 'net-next'.

The mlx4 conflict was a bug fix in 'net' happening in the same
place a constant was being replaced with a more suitable macro.

Signed-off-by: David S. Miller

ipv6: protect skb->sk accesses from recursive dereference inside the stack

2015-04-06T20:12:49+00:00

We should not consult skb->sk for output decisions in xmit recursion
levels > 0 in the stack. Otherwise local socket settings could influence
the result of e.g. tunnel encapsulation process.

ipv6 does not conform with this in three places:

1) ip6_fragment: we do consult ipv6_npinfo for frag_size

2) sk_mc_loop in ipv6 uses skb->sk and checks if we should
   loop the packet back to the local socket

3) ip6_skb_dst_mtu could query the settings from the user socket and
   force a wrong MTU

Furthermore:
In sk_mc_loop we could potentially land in WARN_ON(1) if we use a
PF_PACKET socket ontop of an IPv6-backed vxlan device.

Reuse xmit_recursion as we are currently only interested in protecting
tunnel devices.

Cc: Jiri Pirko 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller

net: Move the comment about unsettable socket-level options to default clause and update its reference.

2015-03-23T20:54:34+00:00

We implement the SO_SNDLOWAT etc not to be settable and return
ENOPROTOOPT per 1003.1g 7.  Move the comment to appropriate
position and update the reference.

Signed-off-by: YOSHIFUJI Hideaki 
Signed-off-by: YOSHIFUJI Hideaki 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2015-03-20T22:51:09+00:00

Conflicts:
	drivers/net/ethernet/emulex/benet/be_main.c
	net/core/sysctl_net_core.c
	net/ipv4/inet_diag.c

The be_main.c conflict resolution was really tricky.  The conflict
hunks generated by GIT were very unhelpful, to say the least.  It
split functions in half and moved them around, when the real actual
conflict only existed solely inside of one function, that being
be_map_pci_bars().

So instead, to resolve this, I checked out be_main.c from the top
of net-next, then I applied the be_main.c changes from 'net' since
the last time I merged.  And this worked beautifully.

The inet_diag.c and sysctl_net_core.c conflicts were simple
overlapping changes, and were easily to resolve.

Signed-off-by: David S. Miller

inet: get rid of central tcp/dccp listener timer

2015-03-20T16:40:25+00:00

One of the major issue for TCP is the SYNACK rtx handling,
done by inet_csk_reqsk_queue_prune(), fired by the keepalive
timer of a TCP_LISTEN socket.

This function runs for awful long times, with socket lock held,
meaning that other cpus needing this lock have to spin for hundred of ms.

SYNACK are sent in huge bursts, likely to cause severe drops anyway.

This model was OK 15 years ago when memory was very tight.

We now can afford to have a timer per request sock.

Timer invocations no longer need to lock the listener,
and can be run from all cpus in parallel.

With following patch increasing somaxconn width to 32 bits,
I tested a listener with more than 4 million active request sockets,
and a steady SYNFLOOD of ~200,000 SYN per second.
Host was sending ~830,000 SYNACK per second.

This is ~100 times more what we could achieve before this patch.

Later, we will get rid of the listener hash and use ehash instead.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: kernel socket should be released in init_net namespace

2015-03-16T20:25:06+00:00

Creating a kernel socket with sock_create_kern() happens in "init_net"
namespace, however, releasing it with sk_release_kernel() occurs in
the current namespace which may be different with "init_net" namespace.
Therefore, we should guarantee that the namespace in which a kernel
socket is created is same as the socket is created.

Signed-off-by: Ying Xue 
Signed-off-by: David S. Miller