From patchwork Fri Jan 26 14:23:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Jones X-Patchwork-Id: 13532665 Received: from out-182.mta1.migadu.com (out-182.mta1.migadu.com [95.215.58.182]) (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 0D3731DDE9 for ; Fri, 26 Jan 2024 14:24:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706279048; cv=none; b=nPXKAq20hV6D2iLNBqVEgfy+qZjPqXjjqGroxLGr0koSa9HEx8jgKrKpJg5PN62Wo45qYO40Ao50hIhbSMeg8yqXEnfeK/BYk50BHp21KUArK1OPUGziWG6vthuq3Cv5lGTrMXfBuWom+mmsiirEdVzSuAnf+krOLTO9BuoORpE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706279048; c=relaxed/simple; bh=aZSlWNk/RnJAVtDTB0t6+fL8GzUU2SL3SGhM76ESfuo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-type; b=NKxpS28n/+TPJzRcGlbUbcNfO5RByB+yQYf0/S/SYgxgz3WezRHl4Cnm9/pySu/sYTrgcu2gHhx3crYTD6QM0hCCKSrT1Rq1h9f/DBzuEavq1H26oyxEgpz052+yWMMj7Gya5xWVC3yIhACrRBvtEBRuuJeRbK0BCR9qOhtqcR4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=NTauUIHo; arc=none smtp.client-ip=95.215.58.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="NTauUIHo" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1706279045; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fbzgEz1s/5JU7chZfU/WobWmghnPKaJfJA+urmjrYhg=; b=NTauUIHo/BOKiUJ0ttoyNZaktD5lN4KZEYshuoW3hC3xot7EQp+Gdts/Ijn7NDP3nz0ysy F1um1bqEpUqWOxc+eFIubpBZxd8KacD6enV4TnVV48Vksec1UgVrhSTP7+EwO78/5HAK11 1+25kSLvllZO44l7f8QECV2E9z902fs= From: Andrew Jones To: kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, kvmarm@lists.linux.dev Cc: ajones@ventanamicro.com, anup@brainfault.org, atishp@atishpatra.org, pbonzini@redhat.com, thuth@redhat.com, alexandru.elisei@arm.com, eric.auger@redhat.com Subject: [kvm-unit-tests PATCH v2 12/24] arm/arm64: Remove spinlocks from on_cpu_async Date: Fri, 26 Jan 2024 15:23:37 +0100 Message-ID: <20240126142324.66674-38-andrew.jones@linux.dev> In-Reply-To: <20240126142324.66674-26-andrew.jones@linux.dev> References: <20240126142324.66674-26-andrew.jones@linux.dev> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-type: text/plain X-Migadu-Flow: FLOW_OUT Remove spinlocks from on_cpu_async() by pulling some of their use into a new function and also by narrowing the locking to a single on_cpu_info structure by introducing yet another cpumask. Signed-off-by: Andrew Jones Acked-by: Thomas Huth Reviewed-by: Eric Auger --- lib/arm/asm/smp.h | 4 +++- lib/arm/smp.c | 37 ++++++++++++++++++++++++++++--------- 2 files changed, 31 insertions(+), 10 deletions(-) diff --git a/lib/arm/asm/smp.h b/lib/arm/asm/smp.h index 9f6d839ab568..f0c0f97a19f8 100644 --- a/lib/arm/asm/smp.h +++ b/lib/arm/asm/smp.h @@ -27,9 +27,11 @@ extern bool cpu0_calls_idle; extern void halt(void); extern void do_idle(void); -extern void smp_boot_secondary(int cpu, secondary_entry_fn entry); extern void on_cpu_async(int cpu, void (*func)(void *data), void *data); extern void on_cpu(int cpu, void (*func)(void *data), void *data); extern void on_cpus(void (*func)(void *data), void *data); +extern void smp_boot_secondary(int cpu, secondary_entry_fn entry); +extern void smp_boot_secondary_nofail(int cpu, secondary_entry_fn entry); + #endif /* _ASMARM_SMP_H_ */ diff --git a/lib/arm/smp.c b/lib/arm/smp.c index c00fda2efb03..e0872a1a72c2 100644 --- a/lib/arm/smp.c +++ b/lib/arm/smp.c @@ -76,12 +76,32 @@ void smp_boot_secondary(int cpu, secondary_entry_fn entry) spin_unlock(&lock); } +void smp_boot_secondary_nofail(int cpu, secondary_entry_fn entry) +{ + spin_lock(&lock); + if (!cpu_online(cpu)) + __smp_boot_secondary(cpu, entry); + spin_unlock(&lock); +} + struct on_cpu_info { void (*func)(void *data); void *data; cpumask_t waiters; }; static struct on_cpu_info on_cpu_info[NR_CPUS]; +static cpumask_t on_cpu_info_lock; + +static bool get_on_cpu_info(int cpu) +{ + return !cpumask_test_and_set_cpu(cpu, &on_cpu_info_lock); +} + +static void put_on_cpu_info(int cpu) +{ + int ret = cpumask_test_and_clear_cpu(cpu, &on_cpu_info_lock); + assert(ret); +} static void __deadlock_check(int cpu, const cpumask_t *waiters, bool *found) { @@ -158,22 +178,21 @@ void on_cpu_async(int cpu, void (*func)(void *data), void *data) assert_msg(cpu != 0 || cpu0_calls_idle, "Waiting on CPU0, which is unlikely to idle. " "If this is intended set cpu0_calls_idle=1"); - spin_lock(&lock); - if (!cpu_online(cpu)) - __smp_boot_secondary(cpu, do_idle); - spin_unlock(&lock); + smp_boot_secondary_nofail(cpu, do_idle); for (;;) { cpu_wait(cpu); - spin_lock(&lock); - if ((volatile void *)on_cpu_info[cpu].func == NULL) - break; - spin_unlock(&lock); + if (get_on_cpu_info(cpu)) { + if ((volatile void *)on_cpu_info[cpu].func == NULL) + break; + put_on_cpu_info(cpu); + } } + on_cpu_info[cpu].func = func; on_cpu_info[cpu].data = data; - spin_unlock(&lock); set_cpu_idle(cpu, false); + put_on_cpu_info(cpu); smp_send_event(); }