From patchwork Wed Jan 24 07:18:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Jones X-Patchwork-Id: 13528669 Received: from out-180.mta0.migadu.com (out-180.mta0.migadu.com [91.218.175.180]) (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 5878F171B0 for ; Wed, 24 Jan 2024 07:18:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.180 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706080734; cv=none; b=REhJRyMiyxvteVkm87JROEssR0G3jn0rJZG817EL7/5rkfcEae8ax83vDHvy76qw2nYK6ONcxk8sSDkSgbZDe/j9Tsz+mSG439aLswuJw+ZkWNnl+d0/HdJHN/8sfKqGHaMvnA6u38HKF2gx9BVl4IBgwW4vsdppnbPAgg3XN5E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706080734; c=relaxed/simple; bh=6wo67D93rRbQbtbOQKA4ikUY5Kpj4XTH6WMeyasllNw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-type; b=SBkKmt14jK1KJFqgGG9cNbHnRqj8h4G/l8um3CiE0AfV5xyACJfzMNuwKfe0kRsK6trbljBSZG9HCPMOSqNvIbuM9xOSZIHcRPnkslGFxkyWzSybWSd+wi0R+lc6NtGOGP80xqhFf9x87jEq5T9FQKRXVQXKf/ZiQ3FooP9YEiw= 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=v1+gzvzU; arc=none smtp.client-ip=91.218.175.180 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="v1+gzvzU" 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=1706080731; 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=dvVL2+Odv7Es+Ec1hfOJxbvWERsCz+M+dPCEcvi0gWc=; b=v1+gzvzUTAm0uDTHxwG4p72GFnwv2MNxL4iSyNhlvs5mv8NSIRcD5YKGCBtHDQwzIb8UMB L6cdBXknaNuHOvudDcnZc2wqbZSKFTUN84orjw184jlcpaMbBvbODpFqfNXW4XpvAKiqwI uxfnqu4aF8nWJ36o1qgEMVbUQ2+domU= 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 12/24] arm/arm64: Remove spinlocks from on_cpu_async Date: Wed, 24 Jan 2024 08:18:28 +0100 Message-ID: <20240124071815.6898-38-andrew.jones@linux.dev> In-Reply-To: <20240124071815.6898-26-andrew.jones@linux.dev> References: <20240124071815.6898-26-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 --- 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(); }