Re: [RFC 2/2] procfs: /proc/sched_debug fails on very very largemachines.

From: Dave Jones
Date: Tue Nov 06 2012 - 16:31:26 EST


On Tue, Nov 06, 2012 at 03:02:21PM -0600, Nathan Zimmer wrote:
> On systems with 4096 cores attemping to read /proc/sched_debug fails.
> We are trying to push all the data into a single kmalloc buffer.
> The issue is on these very large machines all the data will not fit in 4mb.
>
> A better solution is to not us the single_open mechanism but to provide
> our own seq_operations and treat each cpu as an individual record.

Good timing.

This looks like it would solve the problem I just reported here:
https://lkml.org/lkml/2012/11/6/390

That happens even on an 8-way, so it's not just niche machines that have
this problems.

Dave

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