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1db1573bc5
max_threads is initialized once by fork_init()->set_max_threads(), and
thereafter is mostly read in hot path, such as copy_process().
The fact that it is mostly read and not written to makes it candidates for
__read_mostly declarations.
I have already tested on my machine(arm64,256core,kernel-7.1.3) with
'hackbench -P -l 500 -g 100/500/1000/2000' and the results show that there
is an average of 13% improvement in performance.
before patch:
hackbench -g 100 500 1000 2000
1.094 4.651 13.305 36.322
after patch:
hackbench -g 100 500 1000 2000
0.823 4.487 11.107 32.987
Above data are the average values obtained from multiple tests, and there
was indeed some fluctuation in the data during the tests.
Link: https://lore.kernel.org/20260707092354.465847-1-jansef.jian@hj-micro.com
Signed-off-by: JianChunfu <jansef.jian@hj-micro.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>