| Commit message (Collapse) | Author | Age | Files | Lines |
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Backport of http://review.gluster.org/11050
commit eaf3bfa added mod_timers() and successfully screwed up
del_timer() by incorrectly wrapping it within double lock
blocks.
del_timer() was included before the above commit for the sake of
timer API completion, thankfully noone used it till now.
Change-Id: I07a454a216cf09dbb84777a23630e74a1e7f2830
BUG: 1227611
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/11056
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra Bhat <raghavendra@redhat.com>
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Couple of timer-wheel api's to modify timer expiry times:
mod_timer()
mod_timer_pending()
Both the api's perform almost the same job with one minute
difference: mod_timer_pending() modifies timer expiry only
if the timer is pending (i.e. being tracked in timer-wheel).
Change-Id: Iae64934854ccfd6b081b849bff998ae3c3021bac
BUG: 1224647
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/10901
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
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Instantiate a process wide global instance of the timer wheel
data structure. Spawning glusterfs* process with option arg
"--global-timer-wheel" instantiates a global instance of
timer-wheel under global context (->ctx).
Translators can make use of this process wide instance [via a
call to glusterfs_global_timer_wheel()] instead of maintaining
an instance of their own and possibly consuming more memory.
Linux kernel too has a single instance of timer wheel where
subsystems such as IO, networking, etc.. make use of.
Bitrot daemon would be early consumers of this: bitrot translator
instances for multiple volumes would track objects belonging to
their respective bricks in this global expiry tracking data
structure. This is also a first step to move GlusterFS timer
mechanism to use timer-wheel.
> Change-Id: Ie882df607e07acaced846ea269ebf1ece306d6ae
> BUG: 1170075
> Signed-off-by: Venky Shankar <vshankar@redhat.com>
> Reviewed-on: http://review.gluster.org/10380
> Tested-by: NetBSD Build System
> Reviewed-by: Vijay Bellur <vbellur@redhat.com>
> Tested-by: Gluster Build System <jenkins@build.gluster.com>
Change-Id: I35c840daa9996a059699f8ea5af54c76ede7e09c
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Signed-off-by: Gaurav Kumar Garg <ggarg@redhat.com>
BUG: 1220041
Reviewed-on: http://review.gluster.org/10716
Tested-by: Gluster Build System <jenkins@build.gluster.com>
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This patch imports timer-wheel[1] algorithm from the linux
kernel (~/kernel/time/timer.c) with some modifications.
Timer-wheel is an efficent way to track millions of timers for
expiry. This is a variant of the simple but RAM heavy approach
of having a list (timer bucket) for every future second.
Timer-wheel categorizes every future second into a logarithmic
array of arrays. This is done by splitting the 32 bit "timeout"
value into fixed "sliced" bits, thereby each category has a
fixed size array to which buckets are assigned.
A classic split would be 8+6+6+6 (used in this patch) which
results in 256+64+64+64 == 512 buckets. Therefore, the entire
32 bit futuristic timeouts have been mapped into 512 buckets.
[
NOTE:
There are other possible splits, such as "8+8+8+8", but
this patch sticks to the widely used and tested default.
]
Therfore, the first category "holds" timers whose expiry range
is between 1..256, the next cateogry holds 257..16384, third
category 16385..1048576 and so on. When timers are added,
unless it's in the first category, timers with different
timeouts could end up in the same bucket. This means that the
timers are "partially sorted" -- sorted in their highest bits.
The expiry code walks the first array of buckets and exprires
any pending timers (1..256). Next, at time value 257, timers
in the first bucket of the second array is "cascaded" onto
the first category and timers are placed into respective
buckets according to the thier timeout values. Cascading
"brings down" the timers timeout to the coorect bucket
of their respective category. Therefore, timers are sorted
by their highest bits of the timeout value and then by the
lower bits too.
[1] https://lwn.net/Articles/152436/
Change-Id: I1219abf69290961ae9a3d483e11c107c5f49c4e3
BUG: 1170075
Signed-off-by: Venky Shankar <vshankar@redhat.com>
Reviewed-on: http://review.gluster.org/9707
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Vijay Bellur <vbellur@redhat.com>
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