linux.git/net/core/net-sysfs.c, branch v3.4

static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]()

2012-02-24T09:05:59+00:00

So here's a boot tested patch on top of Jason's series that does
all the cleanups I talked about and turns jump labels into a
more intuitive to use facility. It should also address the
various misconceptions and confusions that surround jump labels.

Typical usage scenarios:

        #include 

        struct static_key key = STATIC_KEY_INIT_TRUE;

        if (static_key_false(&key))
                do unlikely code
        else
                do likely code

Or:

        if (static_key_true(&key))
                do likely code
        else
                do unlikely code

The static key is modified via:

        static_key_slow_inc(&key);
        ...
        static_key_slow_dec(&key);

The 'slow' prefix makes it abundantly clear that this is an
expensive operation.

I've updated all in-kernel code to use this everywhere. Note
that I (intentionally) have not pushed through the rename
blindly through to the lowest levels: the actual jump-label
patching arch facility should be named like that, so we want to
decouple jump labels from the static-key facility a bit.

On non-jump-label enabled architectures static keys default to
likely()/unlikely() branches.

Signed-off-by: Ingo Molnar 
Acked-by: Jason Baron 
Acked-by: Steven Rostedt 
Cc: a.p.zijlstra@chello.nl
Cc: mathieu.desnoyers@efficios.com
Cc: davem@davemloft.net
Cc: ddaney.cavm@gmail.com
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu
Signed-off-by: Ingo Molnar

bql: Fix inconsistency between file mode and attr method.

2012-01-17T15:05:55+00:00

There is no store() method for inflight attribute in the
tx-/byte_queue_limits sysfs directory.
So remove S_IWUSR bit.

Signed-off-by: Hiroaki SHIMODA 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: reintroduce missing rcu_assign_pointer() calls

2012-01-12T20:26:56+00:00

commit a9b3cd7f32 (rcu: convert uses of rcu_assign_pointer(x, NULL) to
RCU_INIT_POINTER) did a lot of incorrect changes, since it did a
complete conversion of rcu_assign_pointer(x, y) to RCU_INIT_POINTER(x,
y).

We miss needed barriers, even on x86, when y is not NULL.

Signed-off-by: Eric Dumazet 
CC: Stephen Hemminger 
CC: Paul E. McKenney 
Signed-off-by: David S. Miller

rfs: better sizing of dev_flow_table

2011-12-24T21:13:27+00:00

Aim of this patch is to provide full range of rps_flow_cnt on 64bit arches.

Theorical limit on number of flows is 2^32

Fix some buggy RPS/RFS macros as well.

Signed-off-by: Eric Dumazet 
CC: Tom Herbert 
CC: Xi Wang 
CC: Laurent Chavey 
Signed-off-by: David S. Miller

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

2011-12-23T22:13:56+00:00

Conflicts:
	net/bluetooth/l2cap_core.c

Just two overlapping changes, one added an initialization of
a local variable, and another change added a new local variable.

Signed-off-by: David S. Miller

rps: fix insufficient bounds checking in store_rps_dev_flow_table_cnt()

2011-12-23T03:34:56+00:00

Setting a large rps_flow_cnt like (1 << 30) on 32-bit platform will
cause a kernel oops due to insufficient bounds checking.

	if (count > 1<<30) {
		/* Enforce a limit to prevent overflow */
		return -EINVAL;
	}
	count = roundup_pow_of_two(count);
	table = vmalloc(RPS_DEV_FLOW_TABLE_SIZE(count));

Note that the macro RPS_DEV_FLOW_TABLE_SIZE(count) is defined as:

	... + (count * sizeof(struct rps_dev_flow))

where sizeof(struct rps_dev_flow) is 8.  (1 << 30) * 8 will overflow
32 bits.

This patch replaces the magic number (1 << 30) with a symbolic bound.

Suggested-by: Eric Dumazet 
Signed-off-by: Xi Wang 
Signed-off-by: David S. Miller

bql: fix CONFIG_XPS=n build

2011-12-05T23:30:03+00:00

netdev_queue_release() should be called even if CONFIG_XPS=n
to properly release device reference.

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

bql: Byte queue limits

2011-11-29T17:46:19+00:00

Networking stack support for byte queue limits, uses dynamic queue
limits library.  Byte queue limits are maintained per transmit queue,
and a dql structure has been added to netdev_queue structure for this
purpose.

Configuration of bql is in the tx- sysfs directory for the queue
under the byte_queue_limits directory.  Configuration includes:
limit_min, bql minimum limit
limit_max, bql maximum limit
hold_time, bql slack hold time

Also under the directory are:
limit, current byte limit
inflight, current number of bytes on the queue

Signed-off-by: Tom Herbert 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

xps: Add xps_queue_release function

2011-11-29T17:46:19+00:00

This patch moves the xps specific parts in netdev_queue_release into
its own function which netdev_queue_release can call.  This allows
netdev_queue_release to be more generic (for adding new attributes
to tx queues).

Signed-off-by: Tom Herbert 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: use jump_label to shortcut RPS if not setup

2011-11-17T22:06:08+00:00

Most machines dont use RPS/RFS, and pay a fair amount of instructions in
netif_receive_skb() / netif_rx() / get_rps_cpu() just to discover
RPS/RFS is not setup.

Add a jump_label named rps_needed.

If no device rps_map or global rps_sock_flow_table is setup,
netif_receive_skb() / netif_rx() do a single instruction instead of many
ones, including conditional jumps.

jmp +0    (if CONFIG_JUMP_LABEL=y)

Signed-off-by: Eric Dumazet 
CC: Tom Herbert 
Signed-off-by: David S. Miller