mirror_zfs/include/os/linux/kernel/linux/percpu_compat.h
Serapheim Dimitropoulos ec1fea4516
Use percpu_counter for obj_alloc counter of Linux-backed caches
A previous commit enabled the tracking of object allocations
in Linux-backed caches from the SPL layer for debuggability.
The commit is: 9a170fc6fe54f1e852b6c39630fe5ef2bbd97c16

Unfortunately, it also introduced minor performance regressions
that were highlighted by the ZFS perf test-suite. Within Delphix
we found that the regression would be from -1%, all the way up
to -8% for some workloads.

This commit brings performance back up to par by creating a
separate counter for those caches and making it a percpu in
order to avoid lock-contention.

The initial performance testing was done by myself, and the
final round was conducted by @tonynguien who was also the one
that discovered the regression and highlighted the culprit.

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Closes #10397
2020-06-26 18:06:50 -07:00

45 lines
1.3 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
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* If applicable, add the following below this CDDL HEADER, with the
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*/
/*
* Copyright (c) 2020 by Delphix. All rights reserved.
*/
#ifndef _ZFS_PERCPU_H
#define _ZFS_PERCPU_H
#include <linux/percpu_counter.h>
/*
* 3.18 API change,
* percpu_counter_init() now must be passed a gfp mask which will be
* used for the dynamic allocation of the actual counter.
*/
#ifdef HAVE_PERCPU_COUNTER_INIT_WITH_GFP
#define percpu_counter_init_common(counter, n, gfp) \
percpu_counter_init(counter, n, gfp)
#else
#define percpu_counter_init_common(counter, n, gfp) \
percpu_counter_init(counter, n)
#endif
#endif /* _ZFS_PERCPU_H */