From nobody Wed Dec 17 17:44:47 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BFF731B3F06; Thu, 4 Jul 2024 17:04:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720112674; cv=none; b=fN2yKMfqXfNQuJV/JLA6IPQYwkwX+cLLZv/eX+eoF0A41ot+ONYBg2NkcRdp0ZPVWahwzNUFR784OodVtfi+OVxA/IhaNz4o+XTaRksX/wrRuXWBiEWz/1fH0JIZlST5tCDSI5tw1VH0jrNSmZ8QV4aFDlQZTlXDkIOvBHLCNbg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720112674; c=relaxed/simple; bh=aH/OGvLUI9SJrDSPzGOMJ+Bjl+QQ78TExgwXePwAdS4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=T+67qzquwrQsIha+quyM58k0hmISCVGxH5yR1q2+HIuK27IZfQW1MmzDuox0BfsmKS+2/rvXYPZ9uTCAPd3rVGQ5j60BC0RswzGdxEwCjtYpAU9X37T0rIbyCTaBul0Uy/7KNmpzgrENQVWgBuN9K4zYVgjWMy0Qh85ZfaYWkXY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=1BvjwNtL; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=BzOH1PyB; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="1BvjwNtL"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="BzOH1PyB" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1720112670; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MHWQ5GgUYoJtg5IuAZ3WhjnGiXq5JPhWYhqyDGJpC1Y=; b=1BvjwNtLyO2iJGLwlK0SZK0RFlhFekkVP17WSg7czIyyP9gDOU0lBbOv1CyqnCBw9sov0m vRKtsREuAMBRHYBoXkJCNa7vSlEFb+NjhcI5P3KCHC7iL6ZRpAOHPdhOM63t9vrpwRZeQm DpZh1pkMfvbHOQoZ0wqHsKw42Qd4Th6T81vcuiLl5BZS45i994+FyupPTYN4EL9QDlgDuf 7tVH54bOz/0XOde8ibtJl/FQLbDtsfYmp211EY7/5WtYirVNXPHcx1o/TEgYA7qyPO7zgW rteAarjZBpqnJ1Gc/qk4IXMNLHmSL5gW9DxlnTggjrTdJ0lWXMZveJMRsLIjqQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1720112670; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MHWQ5GgUYoJtg5IuAZ3WhjnGiXq5JPhWYhqyDGJpC1Y=; b=BzOH1PyBNSVd6ur7CbdUDdPBVz/8DWbcCnFPzNiks5GrqiyDSlVxmMhieFfKGW3Gw/SapY TkEbquVojCLDh/Bg== To: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Adrian Hunter , Alexander Shishkin , Arnaldo Carvalho de Melo , Frederic Weisbecker , Ian Rogers , Ingo Molnar , Jiri Olsa , Kan Liang , Marco Elver , Mark Rutland , Namhyung Kim , Peter Zijlstra , Thomas Gleixner , Sebastian Andrzej Siewior Subject: [PATCH v5 4/7] perf: Shrink the size of the recursion counter. Date: Thu, 4 Jul 2024 19:03:38 +0200 Message-ID: <20240704170424.1466941-5-bigeasy@linutronix.de> In-Reply-To: <20240704170424.1466941-1-bigeasy@linutronix.de> References: <20240704170424.1466941-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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. Tested-by: Marco Elver Signed-off-by: Sebastian Andrzej Siewior --- 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 1273be84392cf..ad57944b6c40e 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)); } =20 -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 c278aefa94e76..bd4b81bf63b6d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9776,7 +9776,7 @@ struct swevent_htable { int hlist_refcount; =20 /* Recursion avoidance in each contexts */ - int recursion[PERF_NR_CONTEXTS]; + u8 recursion[PERF_NR_CONTEXTS]; }; =20 static DEFINE_PER_CPU(struct swevent_htable, swevent_htable); diff --git a/kernel/events/internal.h b/kernel/events/internal.h index 5150d5f84c033..f9a3244206b20 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -208,7 +208,7 @@ arch_perf_out_copy_user(void *dst, const void *src, uns= igned long n) =20 DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user) =20 -static inline int get_recursion_context(int *recursion) +static inline int get_recursion_context(u8 *recursion) { unsigned char rctx =3D interrupt_context_level(); =20 @@ -221,7 +221,7 @@ static inline int get_recursion_context(int *recursion) return rctx; } =20 -static inline void put_recursion_context(int *recursion, int rctx) +static inline void put_recursion_context(u8 *recursion, int rctx) { barrier(); recursion[rctx]--; --=20 2.45.2