Re: [PATCH] writeback: remove unnecessary wait in throttle_vm_writeout()

From: Frank Ch. Eigler
Date: Fri Sep 28 2007 - 15:51:22 EST



Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx> writes:

>> [...]
>> > I totally agree with Ingo here. Having a basic instrumentation that is
>> > enabled by default will help to identify code paths causing unexpected
>> > delays in the kernel. [...]
>
>> It is. See: CONFIG_VM_EVENT_COUNTERS and all the other vm specific
>> crap littered in /proc/ (buddyinfo, zoneinfo, meminfo, etc). [...]

> Isn't the actual instrumentation present in the VM subsystem
> consisting mostly of event counters ? This kind of profiling
> provides limited help in following specific delays in the
> kernel. [...]

These existing VM events/counters could be a good target for a second
worked-out example (after blktrace) of reimplementation using generic
markers.

- FChE
-
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