From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 1AA1415DBC9 for ; Thu, 1 Feb 2024 09:34:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706780071; cv=none; b=BT1MMAgM6QZH34OFthunTmp6NH/3ndWEDHCozxkzwbDmckqb7KPQ7eSSnu/E+HDsnciCPdJmCQYVA6zpJyAwvsGO68fm9ecmiExc3sUtyqasUtGbOv7UVwajUXkauPnrjKyi750ridkY8QqlP4PUPbelAxKf17e/3Ueuj01tMhw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706780071; c=relaxed/simple; bh=jbCMGhadY8+aTcrS8iELZ3H62oZgYB3Aqj3D9xUwvsI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=I9kOh57UQA01Ja8bYdqrUyc+zzSKzOnFY/jKBgmYXs4pafkpbWE3zi9X/xd3e068E/nFoAHkUdf2maFUcIZHmlK1u5WwbxW73lQgztSTXhhhoDcoYVhj9uV0pniBqdAshBtoEec9IUE+WuqZUFTrvWHnv8c0xELCz6loKNSEOLY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=GkZoVhPV; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="GkZoVhPV" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706780069; h=from:from:reply-to: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=QbKXlj2qJmYcwwoAL264/SJMr9ivxzGCitMWNoXprno=; b=GkZoVhPVMsfF/vCBemrY899nIFe3FAkP+Vo55ztbaQJ9MbgG6wDvKljFurI2nkWJEkcpA/ hk04Ki6MAzXGuvnMnoqRY69Dnn7sW8k6HEo5GqG1aORekiZjaKlvLGV3lX1+cUM4/7xz6x PbpB/aU+gZly5UJ/mjp6XdWro3VqsRw= Received: from mail-lf1-f69.google.com (mail-lf1-f69.google.com [209.85.167.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-117-vpbPSfLgMUGnON2C_464ZA-1; Thu, 01 Feb 2024 04:34:27 -0500 X-MC-Unique: vpbPSfLgMUGnON2C_464ZA-1 Received: by mail-lf1-f69.google.com with SMTP id 2adb3069b0e04-50e55470b49so695631e87.0 for ; Thu, 01 Feb 2024 01:34:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706780066; x=1707384866; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:reply-to:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=QbKXlj2qJmYcwwoAL264/SJMr9ivxzGCitMWNoXprno=; b=WWd72uy7W4ECXEZucCRjPdlFpu+bqN1eZGXwkf5PlcwDVpRhTUQ46pO0zl3WPNrKTK wKpIUYgkhTkU/1+Qk0MlrO85ssSpk2nrv+sZSM9qe7fOXyxUKEfh0XfWTnwqAiZmELMe gRCTKEWXZ5ms1VVUI14RLAZxcUv3TklmIlTGdPIZ8MEfG3QdeK3NXwPxM4AvLpaL8RPx qbWGXee1/XJHYSnVl+0ONvVOkpG4ZKAPo1ucteMrVotj6VohhOkQhTBNp5u3mFJ65Y6Y pOkwb+jbnieigfF5bVNQMy2WyQpaN2Bp16ob0bYvBEn5lt1jFbx/eajoTZ5xCIGYIVqu fxHg== X-Gm-Message-State: AOJu0YwIwElPsFko19ko4PUVlK0amaa8wcevJO71g7TEmzh5oP0sBIPK vOM8NzyMVpFD411bHYSaGtKiOuGxoQjYiEi1+bOZrXAJROLKCK/N1cSjQWSs5migm7v1fEM3Sbc w91DMuSlhOlgffXXy5G3BJ1mG1BVKDOytW1PAH37Iz1bKelWhUg== X-Received: by 2002:ac2:42c2:0:b0:511:2da1:d34f with SMTP id n2-20020ac242c2000000b005112da1d34fmr946656lfl.68.1706780066375; Thu, 01 Feb 2024 01:34:26 -0800 (PST) X-Google-Smtp-Source: AGHT+IGvccMcskijAMysxvD7yYFYGNPus6UL4rYmCZTFAmOefTGXD1uzbrcKE/pB3OC9GGXxacmo0A== X-Received: by 2002:ac2:42c2:0:b0:511:2da1:d34f with SMTP id n2-20020ac242c2000000b005112da1d34fmr946637lfl.68.1706780066004; Thu, 01 Feb 2024 01:34:26 -0800 (PST) X-Forwarded-Encrypted: i=0; AJvYcCW3PpPY/C3y3Z+XF8gr1uRDBGy7Qg283nXZee1wNMd3gy39QCZOZf10LIBFH6YXs0b+50OaE8RjhdGD8VFB2FnUdNmL8b5NBXWBnJS1OK7z3QxnABKWgjyouvVzC5OaL6OYnz5vZvOXEOi86j5RF8bCpryXqotjRcZTMKvg7G9PARh+rqSOtT3XHqrhlYMJHAVYvMil7gFnUeMVO2y0dQzplbsqppc/UWjyNjj16Ni9izNUJJq98HhfTo+1dwN0Kka34iMyySTdVulFR/XmNnoEYkGJf1jUa3qt2qM2hRqG+s/wnowbWFE= Received: from ?IPV6:2a01:e0a:59e:9d80:527b:9dff:feef:3874? ([2a01:e0a:59e:9d80:527b:9dff:feef:3874]) by smtp.gmail.com with ESMTPSA id s15-20020a05600c45cf00b0040e3635ca65sm3890448wmo.2.2024.02.01.01.34.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 01 Feb 2024 01:34:25 -0800 (PST) Message-ID: Date: Thu, 1 Feb 2024 10:34:24 +0100 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Reply-To: eric.auger@redhat.com Subject: Re: [kvm-unit-tests PATCH v2 12/24] arm/arm64: Remove spinlocks from on_cpu_async Content-Language: en-US To: Andrew Jones , 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 References: <20240126142324.66674-26-andrew.jones@linux.dev> <20240126142324.66674-38-andrew.jones@linux.dev> From: Eric Auger In-Reply-To: <20240126142324.66674-38-andrew.jones@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/26/24 15:23, Andrew Jones wrote: > 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 Eric > --- > 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(); > } >