diff options
| author | Huang Ying <ying.huang@intel.com> | 2023-10-16 13:29:59 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-25 16:47:10 -0700 |
| commit | 90b41691b9881376fe784e13b5766ec3676fdb55 (patch) | |
| tree | 79d97f1a03ff78dabdbdf9000c5bc269eaaf50a0 /include/linux/mmzone.h | |
| parent | c0a242394cb980bd00e1f61dc8aacb453d2bbe6a (diff) | |
mm: add framework for PCP high auto-tuning
The page allocation performance requirements of different workloads are
usually different. So, we need to tune PCP (per-CPU pageset) high to
optimize the workload page allocation performance. Now, we have a system
wide sysctl knob (percpu_pagelist_high_fraction) to tune PCP high by hand.
But, it's hard to find out the best value by hand. And one global
configuration may not work best for the different workloads that run on
the same system. One solution to these issues is to tune PCP high of each
CPU automatically.
This patch adds the framework for PCP high auto-tuning. With it,
pcp->high of each CPU will be changed automatically by tuning algorithm at
runtime. The minimal high (pcp->high_min) is the original PCP high value
calculated based on the low watermark pages. While the maximal high
(pcp->high_max) is the PCP high value when percpu_pagelist_high_fraction
sysctl knob is set to MIN_PERCPU_PAGELIST_HIGH_FRACTION. That is, the
maximal pcp->high that can be set via sysctl knob by hand.
It's possible that PCP high auto-tuning doesn't work well for some
workloads. So, when PCP high is tuned by hand via the sysctl knob, the
auto-tuning will be disabled. The PCP high set by hand will be used
instead.
This patch only adds the framework, so pcp->high will be set to
pcp->high_min (original default) always. We will add actual auto-tuning
algorithm in the following patches in the series.
Link: https://lkml.kernel.org/r/20231016053002.756205-7-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/mmzone.h')
| -rw-r--r-- | include/linux/mmzone.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index e6cc2238c65f..775abc899e80 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -693,6 +693,8 @@ struct per_cpu_pages { spinlock_t lock; /* Protects lists field */ int count; /* number of pages in the list */ int high; /* high watermark, emptying needed */ + int high_min; /* min high watermark */ + int high_max; /* max high watermark */ int batch; /* chunk size for buddy add/remove */ u8 flags; /* protected by pcp->lock */ u8 alloc_factor; /* batch scaling factor during allocate */ @@ -852,7 +854,8 @@ struct zone { * the high and batch values are copied to individual pagesets for * faster access */ - int pageset_high; + int pageset_high_min; + int pageset_high_max; int pageset_batch; #ifndef CONFIG_SPARSEMEM |