Commit Graph

4 Commits

Author SHA1 Message Date
Dennis Zhou (Facebook) 6b9b6f3994 percpu: expose pcpu_nr_empty_pop_pages in pcpu_stats
Percpu memory holds a minimum threshold of pages that are populated
in order to serve atomic percpu memory requests. This change makes it
easier to verify that there are a minimum number of populated pages
lying around.

Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2017-07-17 10:46:58 -04:00
Dennis Zhou 303abfdf76 percpu: fix early calls for spinlock in pcpu_stats
From 2c06e795162cb306c9707ec51d3e1deadb37f573 Mon Sep 17 00:00:00 2001
From: Dennis Zhou <dennisz@fb.com>
Date: Wed, 21 Jun 2017 10:17:09 -0700

Commit 30a5b5367e ("percpu: expose statistics about percpu memory via
debugfs") introduces percpu memory statistics. pcpu_stats_chunk_alloc
takes the spin lock and disables/enables irqs on creation of a chunk. Irqs
are not enabled when the first chunk is initialized and thus kernels are
failing to boot with kernel debugging enabled. Fixed by changing _irq to
_irqsave and _irqrestore.

Fixes: 30a5b5367e ("percpu: expose statistics about percpu memory via debugfs")
Signed-off-by: Dennis Zhou <dennisz@fb.com>
Reported-by: Alexander Levin <alexander.levin@verizon.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2017-06-21 13:53:52 -04:00
Dennis Zhou 30a5b5367e percpu: expose statistics about percpu memory via debugfs
There is limited visibility into the use of percpu memory leaving us
unable to reason about correctness of parameters and overall use of
percpu memory. These counters and statistics aim to help understand
basic statistics about percpu memory such as number of allocations over
the lifetime, allocation sizes, and fragmentation.

New Config: PERCPU_STATS

Signed-off-by: Dennis Zhou <dennisz@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2017-06-20 15:31:38 -04:00
Dennis Zhou 8fa3ed8014 percpu: migrate percpu data structures to internal header
Migrates pcpu_chunk definition and a few percpu static variables to an
internal header file from mm/percpu.c. These will be used with debugfs
to expose statistics about percpu memory improving visibility regarding
allocations and fragmentation.

Signed-off-by: Dennis Zhou <dennisz@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2017-06-20 15:31:28 -04:00