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Shrikanth HegdeandPeter Zijlstra
5bc6ab2d42
Now, that cpu_smt_mask is defined as cpumask_of(cpu) for CONFIG_SCHED_SMT=n, it is possible to get rid of the ifdeffery. Effectively, - This makes sched_smt_present is defined always - cpumask_weight(cpumask_of(cpu)) == 1. So sched_smt_present_inc/dec will never enable the sched_smt_present. Which is expected. - Paths that were compile-time eliminated become runtime guarded using static keys. - Defines set_idle_cores, test_idle_cores, etc which could likely benefit the CONFIG_SCHED_SMT=n systems to use the same optimizations within the LLC at wakeups. - This will expose sched_smt_present symbol for CONFIG_SCHED_SMT=n. Likely not a concern. - There is a bloat of code CONFIG_SCHED_SMT=n. (NR_CPUS=2048) add/remove: 24/18 grow/shrink: 26/28 up/down: 6396/-3188 (3208) Total: Before=30629880, After=30633088, chg +0.01% - No code bloat for CONFIG_SCHED_SMT=y, which is expected. - Add comments around stop_core_cpuslocked on why ifdefs are not removed. - This leaves the remaining uses of CONFIG_SCHED_SMT mainly for topology building bits which has a policy based decision. Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Reviewed-by: Valentin Schneider <vschneid@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Tested-by: K Prateek Nayak <kprateek.nayak@amd.com> Link: https://patch.msgid.link/20260515172456.542799-3-sshegde@linux.ibm.com
17 lines
343 B
C
17 lines
343 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_SMT_H
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#define _LINUX_SCHED_SMT_H
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#include <linux/static_key.h>
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extern struct static_key_false sched_smt_present;
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static __always_inline bool sched_smt_active(void)
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{
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return static_branch_likely(&sched_smt_present);
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}
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void arch_smt_update(void);
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#endif /* _LINUX_SCHED_SMT_H */
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