From 15e0bd29c0ac8b2b319fd21b6193a55bcd90eddf Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Thu, 4 Jul 2024 19:03:38 +0200 Subject: [PATCH] perf: Shrink the size of the recursion counter. BugLink: https://bugs.launchpad.net/bugs/2089700 There are four recursion counter, one for each context. The type of the counter is `int' but the counter is used as `bool' since it is only incremented if zero. The main goal here is to shrink the whole struct into 32bit int which can later be added task_struct into an existing hole. Reduce the type of the recursion counter to an unsigned char, keep the increment/ decrement operation. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Tested-by: Marco Elver Link: https://lore.kernel.org/r/20240704170424.1466941-5-bigeasy@linutronix.de (cherry picked from 5af42f928f3ac555c228740fb4a92d05b19fdd49) Signed-off-by: Kevin Becker Acked-by: Magali Lemes Acked-by: John Cabaj --- kernel/events/callchain.c | 2 +- kernel/events/core.c | 2 +- kernel/events/internal.h | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index 1273be84392c..ad57944b6c40 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -29,7 +29,7 @@ static inline size_t perf_callchain_entry__sizeof(void) sysctl_perf_event_max_contexts_per_stack)); } -static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]); +static DEFINE_PER_CPU(u8, callchain_recursion[PERF_NR_CONTEXTS]); static atomic_t nr_callchain_events; static DEFINE_MUTEX(callchain_mutex); static struct callchain_cpus_entries *callchain_cpus_entries; diff --git a/kernel/events/core.c b/kernel/events/core.c index d6e0f04d7c8c..a6588de06a23 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9691,7 +9691,7 @@ struct swevent_htable { int hlist_refcount; /* Recursion avoidance in each contexts */ - int recursion[PERF_NR_CONTEXTS]; + u8 recursion[PERF_NR_CONTEXTS]; }; static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); diff --git a/kernel/events/internal.h b/kernel/events/internal.h index f376b057320c..bae0f7778f88 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -209,7 +209,7 @@ arch_perf_out_copy_user(void *dst, const void *src, unsigned long n) DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user) -static inline int get_recursion_context(int *recursion) +static inline int get_recursion_context(u8 *recursion) { unsigned char rctx = interrupt_context_level(); @@ -222,7 +222,7 @@ static inline int get_recursion_context(int *recursion) return rctx; } -static inline void put_recursion_context(int *recursion, int rctx) +static inline void put_recursion_context(u8 *recursion, int rctx) { barrier(); recursion[rctx]--;