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sched: Refactor task_struct to use numa_faults instead of numa_* pointers

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This patch simplifies task_struct by removing the four numa_* pointers
in the same array and replacing them with the array pointer. By doing this,
on x86_64, the size of task_struct is reduced by 3 ulong pointers (24 bytes on
x86_64).

A new parameter is added to the task_faults_idx function so that it can return
an index to the correct offset, corresponding with the old precalculated
pointers.

All of the code in sched/ that depended on task_faults_idx and numa_* was
changed in order to match the new logic.

Signed-off-by: Iulia Manda <iulia.manda21@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: dave@stgolabs.net
Cc: riel@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20141031001331.GA30662@winterfell
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Iulia Manda
2014-10-31 02:13:31 +02:00
committed by Ingo Molnar
parent cad3bb32e1
commit 44dba3d5d6
5 changed files with 80 additions and 75 deletions
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31
include/linux/sched.h
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@@ -1597,27 +1597,22 @@ struct task_struct {
struct numa_group *numa_group;
/*
* Exponential decaying average of faults on a per-node basis.
* Scheduling placement decisions are made based on the these counts.
* The values remain static for the duration of a PTE scan
* numa_faults is an array split into four regions:
* faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
* in this precise order.
*
* faults_memory: Exponential decaying average of faults on a per-node
* basis. Scheduling placement decisions are made based on these
* counts. The values remain static for the duration of a PTE scan.
* faults_cpu: Track the nodes the process was running on when a NUMA
* hinting fault was incurred.
* faults_memory_buffer and faults_cpu_buffer: Record faults per node
* during the current scan window. When the scan completes, the counts
* in faults_memory and faults_cpu decay and these values are copied.
*/
unsigned long *numa_faults_memory;
unsigned long *numa_faults;
unsigned long total_numa_faults;
/*
* numa_faults_buffer records faults per node during the current
* scan window. When the scan completes, the counts in
* numa_faults_memory decay and these values are copied.
*/
unsigned long *numa_faults_buffer_memory;
/*
* Track the nodes the process was running on when a NUMA hinting
* fault was incurred.
*/
unsigned long *numa_faults_cpu;
unsigned long *numa_faults_buffer_cpu;
/*
* numa_faults_locality tracks if faults recorded during the last
* scan window were remote/local. The task scan period is adapted