Revert "ksm: check and skip page, if it is already scanned"

This reverts commit 3e845d3884f45d0d53e1b81a99139a0a37d1873b.
lib/int_sqrt.c: optimize square root algorithm

Signed-off-by: flar2 <asegaert@gmail.com>
fix CIFS

Signed-off-by: flar2 <asegaert@gmail.com>
softirq: reduce latencies

In various network workloads, __do_softirq() latencies can be up
to 20 ms if HZ=1000, and 200 ms if HZ=100.

This is because we iterate 10 times in the softirq dispatcher,
and some actions can consume a lot of cycles.

This patch changes the fallback to ksoftirqd condition to :

- A time limit of 2 ms.
- need_resched() being set on current task

When one of this condition is met, we wakeup ksoftirqd for further
softirq processing if we still have pending softirqs.

Using need_resched() as the only condition can trigger RCU stalls,
as we can keep BH disabled for too long.

I ran several benchmarks and got no significant difference in
throughput, but a very significant reduction of latencies (one order
of magnitude) :

In following bench, 200 antagonist "netperf -t TCP_RR" are started in
background, using all available cpus.

Then we start one "netperf -t TCP_RR", bound to the cpu handling the NIC
IRQ (hard+soft)

Before patch :

# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=550110.424
MIN_LATENCY=146858
MAX_LATENCY=997109
P50_LATENCY=305000
P90_LATENCY=550000
P99_LATENCY=710000
MEAN_LATENCY=376989.12
STDDEV_LATENCY=184046.92

After patch :

# netperf -H 7.7.7.84 -t TCP_RR -T2,2 -- -k
RT_LATENCY,MIN_LATENCY,MAX_LATENCY,P50_LATENCY,P90_LATENCY,P99_LATENCY,MEAN_LATENCY,STDDEV_LATENCY
MIGRATED TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET
to 7.7.7.84 () port 0 AF_INET : first burst 0 : cpu bind
RT_LATENCY=40545.492
MIN_LATENCY=9834
MAX_LATENCY=78366
P50_LATENCY=33583
P90_LATENCY=59000
P99_LATENCY=69000
MEAN_LATENCY=38364.67
STDDEV_LATENCY=12865.26

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Miller <davem@davemloft.net>
Cc: Tom Herbert <therbert@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
Signed-off-by: flar2 <asegaert@gmail.com>
enable cfs
usb: gadget: mass_storage: added sysfs entry for cdrom to LUNs

This patch adds a "cdrom" sysfs entry for each mass_storage LUN, just
like "ro" sysfs entry. This allows switching between USB and CD-ROM
emulation without reinserting the module or recompiling the kernel.

Change-Id: Idf83c74815b1ad370428ab9d3e5503d5f7bcd3b6

Signed-off-by: flar2 <asegaert@gmail.com>
remove some annoying log spam

Signed-off-by: flar2 <asegaert@gmail.com>

Conflicts:
	drivers/i2c/chips/cm3629.c
enabe msm freq limiter
Revert "enable cfs"

This reverts commit af87cfcfdc16c0c7c7e5259747a242111f6e98ed.
Revert "fix CIFS"

This reverts commit b96821ed883e578712428533bd9f04093d7d7330.
Revert "enabe msm freq limiter"

This reverts commit 9b6aabcaf3052a928ba4bdb038b2a76495ce5790.