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Eric Dumazet 29b4433d99 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>
2010-10-12 12:35:25 -07:00
..
accessibility
acpi Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2010-10-01 10:54:58 -07:00
amba
ata ahci: fix module refcount breakage introduced by libahci split 2010-09-28 15:14:51 -04:00
atm Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-10-11 12:30:34 -07:00
auxdisplay
base PM: Prevent waiting forever on asynchronous resume after failing suspend 2010-09-09 00:49:43 +02:00
block Fix pktcdvd ioctl dev_minor range check 2010-09-27 16:29:06 -07:00
bluetooth
cdrom
char ipmi: fix hardcoded ipmi device exit path warning 2010-09-22 17:22:40 -07:00
clocksource
connector
cpufreq
cpuidle cpuidle: Fix typos 2010-09-28 23:30:38 -04:00
crypto
dca dca: disable dca on IOAT ver.3.0 multiple-IOH platforms 2010-09-17 20:08:21 -07:00
dio
dma dmaengine: fix interrupt clearing for mv_xor 2010-09-23 14:14:22 -07:00
edac i7core_edac: fix panic in udimm sysfs attributes registration 2010-10-01 10:50:58 -07:00
eisa
firewire Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-10-06 19:39:31 -07:00
firmware
gpio gpio: sx150x: correct and refine reset-on-probe behavior 2010-09-09 18:57:24 -07:00
gpu Merge branch 'drm-intel-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ickle/drm-intel 2010-10-04 11:10:26 -07:00
hid HID: fix hiddev's use of usb_find_interface 2010-09-14 10:58:42 +02:00
hwmon hwmon: f71882fg: use a muxed resource lock for the Super I/O port 2010-10-03 05:57:04 -07:00
i2c i2c-s3c2410: fix calculation of SDA line delay 2010-10-01 00:00:35 +01:00
ide Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-2.6 2010-09-19 11:06:34 -07:00
idle intel_idle: Voluntary leave_mm before entering deeper 2010-09-30 21:19:22 -04:00
ieee1394 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-09-09 22:27:33 -07:00
ieee802154
infiniband net: percpu net_device refcount 2010-10-12 12:35:25 -07:00
input
isdn Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-10-11 12:30:34 -07:00
leds leds: leds-ns2: fix locking 2010-09-19 22:43:42 -04:00
lguest
macintosh
mca
md md: fix v1.x metadata update when a disk is missing. 2010-09-17 13:53:28 +10:00
media
memstick
message
mfd mfd: Fix max8925 irq control bit incorrect setting 2010-09-29 10:14:53 +02:00
misc vmware balloon: rename module 2010-09-22 17:22:38 -07:00
mmc mmc: sdhci-s3c: fix NULL ptr access in sdhci_s3c_remove 2010-09-26 16:27:05 -04:00
mtd fix OMAP2 MTD build failure 2010-09-29 13:17:56 -07:00
net bnx2x: Fixing a typo: added a missing RSS enablement 2010-10-12 12:30:28 -07:00
nubus
of
oprofile
parisc
parport
pci Merge branch 'meego-7093' into idle-release 2010-09-28 23:30:58 -04:00
pcmcia pcmcia: pd6729: Fix error path 2010-09-26 15:54:25 +02:00
platform thinkpad-acpi: avoid keymap pitfall 2010-09-23 15:42:04 -04:00
pnp
power apm_power: Add missing break statement 2010-09-08 14:35:10 +04:00
pps
ps3
rapidio
regulator regulator: max8649 - fix setting extclk_freq 2010-10-02 14:19:45 +01:00
rtc rtc: s3c: balance state changes of wakeup flag 2010-09-22 17:22:40 -07:00
s390 Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-10-06 19:39:31 -07:00
sbus
scsi Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-10-06 19:39:31 -07:00
serial drivers/serial/mrst_max3110.c needs linux/irq.h 2010-10-01 10:50:58 -07:00
sfi
sh
sn
spi of/spi: Fix OF-style driver binding of spi devices 2010-10-02 21:28:29 -06:00
ssb
staging Staging: ti-st: remove st_get_plat_device 2010-09-24 11:04:32 -07:00
tc
telephony
thermal
uio
usb Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2010-10-06 19:39:31 -07:00
uwb uwb: use '%pM' format to print MAC address 2010-09-13 20:02:54 -07:00
vhost vhost: max s/g to match qemu 2010-10-05 13:33:43 +02:00
video Merge master.kernel.org:/home/rmk/linux-2.6-arm 2010-09-27 12:32:36 -07:00
virtio
vlynq
w1
watchdog watchdog: Enable NXP LPC32XX support in Kconfig (resend) 2010-09-15 18:43:58 +00:00
xen xen: do not set xenstored_ready before xenbus_probe on hvm 2010-10-05 13:37:28 +01:00
zorro
Kconfig
Makefile Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 2010-09-17 10:23:08 -07:00