From: Christophe Leroy <christophe.leroy@csgroup.eu>
Date: Mon, 18 Aug 2025 09:57:15 +0000 (+0200)
Subject: perf: Completely remove possibility to override MAX_NR_CPUS
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=6f8fb022ef2c6694e47f6e2f5676eb63be66c208;p=users%2Fhch%2Fmisc.git

perf: Completely remove possibility to override MAX_NR_CPUS

Commit 21b8732eb447 ("perf tools: Allow overriding MAX_NR_CPUS at
compile time") added the capability to override MAX_NR_CPUS. At
that time it was necessary to reduce the huge amount of RAM used
by static stats variables.

But this has been unnecessary since commit 6a1e2c5c2673 ("perf stat:
Remove a set of shadow stats static variables"), and
commit e8399d34d568 ("libperf cpumap: Hide/reduce scope of
MAX_NR_CPUS") broke the build in that case because it failed to
add the guard around the new definition of MAX_NR_CPUS.

So cleanup things and remove guards completely to officialise it
is not necessary anymore to override MAX_NR_CPUS.

Fixes: e8399d34d568d61c ("libperf cpumap: Hide/reduce scope of MAX_NR_CPUS")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/all/8c8553387ebf904a9e5a93eaf643cb01164d9fb3.1736188471.git.christophe.leroy@csgroup.eu/
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---

diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 3cb40965549f..e004178472d9 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -2,9 +2,7 @@
 #ifndef _PERF_PERF_H
 #define _PERF_PERF_H
 
-#ifndef MAX_NR_CPUS
 #define MAX_NR_CPUS			4096
-#endif
 
 enum perf_affinity {
 	PERF_AFFINITY_SYS = 0,
diff --git a/tools/perf/util/bpf_skel/kwork_top.bpf.c b/tools/perf/util/bpf_skel/kwork_top.bpf.c
index 73e32e063030..6673386302e2 100644
--- a/tools/perf/util/bpf_skel/kwork_top.bpf.c
+++ b/tools/perf/util/bpf_skel/kwork_top.bpf.c
@@ -18,9 +18,7 @@ enum kwork_class_type {
 };
 
 #define MAX_ENTRIES     102400
-#ifndef MAX_NR_CPUS
 #define MAX_NR_CPUS     4096
-#endif
 #define PF_KTHREAD      0x00200000
 #define MAX_COMMAND_LEN 16