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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-10-11 10:22:12 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-10-12 12:35:25 -0700 |
| commit | 29b4433d991c88d86ca48a4c1cc33c671475be4b (patch) | |
| tree | 2ad21b86aab8193c4533820c40cd31af97a7377f /drivers/infiniband/hw/nes/nes_cm.c | |
| parent | f0b9f4725180ea58c8da78b3de0b4e0ad180fc2c (diff) | |
| download | kernel_samsung_smdk4412-29b4433d991c88d86ca48a4c1cc33c671475be4b.zip kernel_samsung_smdk4412-29b4433d991c88d86ca48a4c1cc33c671475be4b.tar.gz kernel_samsung_smdk4412-29b4433d991c88d86ca48a4c1cc33c671475be4b.tar.bz2 | |
net: percpu net_device refcount
We tried very hard to remove all possible dev_hold()/dev_put() pairs in
network stack, using RCU conversions.
There is still an unavoidable device refcount change for every dst we
create/destroy, and this can slow down some workloads (routers or some
app servers, mmap af_packet)
We can switch to a percpu refcount implementation, now dynamic per_cpu
infrastructure is mature. On a 64 cpus machine, this consumes 256 bytes
per device.
On x86, dev_hold(dev) code :
before
lock incl 0x280(%ebx)
after:
movl 0x260(%ebx),%eax
incl fs:(%eax)
Stress bench :
(Sending 160.000.000 UDP frames,
IP route cache disabled, dual E5540 @2.53GHz,
32bit kernel, FIB_TRIE)
Before:
real 1m1.662s
user 0m14.373s
sys 12m55.960s
After:
real 0m51.179s
user 0m15.329s
sys 10m15.942s
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/infiniband/hw/nes/nes_cm.c')
| -rw-r--r-- | drivers/infiniband/hw/nes/nes_cm.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c index 61e0efd..6220d9d 100644 --- a/drivers/infiniband/hw/nes/nes_cm.c +++ b/drivers/infiniband/hw/nes/nes_cm.c @@ -2701,7 +2701,7 @@ static int nes_disconnect(struct nes_qp *nesqp, int abrupt) nesibdev = nesvnic->nesibdev; nes_debug(NES_DBG_CM, "netdev refcnt = %u.\n", - atomic_read(&nesvnic->netdev->refcnt)); + netdev_refcnt_read(nesvnic->netdev)); if (nesqp->active_conn) { @@ -2791,7 +2791,7 @@ int nes_accept(struct iw_cm_id *cm_id, struct iw_cm_conn_param *conn_param) atomic_inc(&cm_accepts); nes_debug(NES_DBG_CM, "netdev refcnt = %u.\n", - atomic_read(&nesvnic->netdev->refcnt)); + netdev_refcnt_read(nesvnic->netdev)); /* allocate the ietf frame and space for private data */ nesqp->ietf_frame = pci_alloc_consistent(nesdev->pcidev, |