From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C0BA6C43217 for ; Fri, 7 Jan 2022 11:55:58 +0000 (UTC) Received: from localhost ([::1]:39436 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n5nqf-0005xO-UG for qemu-devel@archiver.kernel.org; Fri, 07 Jan 2022 06:55:57 -0500 Received: from eggs.gnu.org ([209.51.188.92]:45424) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n5n3B-0001Cq-Dy for qemu-devel@nongnu.org; Fri, 07 Jan 2022 06:04:49 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:54316) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n5n38-0001zI-W5 for qemu-devel@nongnu.org; Fri, 07 Jan 2022 06:04:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641553486; 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=4akHXGYHIwd7HNeqwa3gMQKaZ7VYtAKPZ8TAtHqI2Gc=; b=GOjeRGz987bpStcYJr1GDItKayqAaFVNXR8hTA7Qc5YY1IQUYPWHtzDq8Co25jeT5R1jfe qrzhJN2CyyCR008QlhTeM+OxOedZe3/k4IuhBIyJ2dCWF84kH+BnUNuF6Lnugq5OYEKUQS 2jodqpGBUmURpDqgH6X8OXUfNTE2/cI= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-77-_kuNyE-XPvOMWk9xyiBZfA-1; Fri, 07 Jan 2022 06:04:45 -0500 X-MC-Unique: _kuNyE-XPvOMWk9xyiBZfA-1 Received: by mail-wr1-f71.google.com with SMTP id h24-20020adfaa98000000b001a4dbe0c51fso1780929wrc.0 for ; Fri, 07 Jan 2022 03:04:44 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=4akHXGYHIwd7HNeqwa3gMQKaZ7VYtAKPZ8TAtHqI2Gc=; b=5tc77OTzpPVLzezSSi9bmN8fO4ph06e++qv5mcn+lL+D1yVST7/9OVnaYcNHJuOoJa t5xxOCrx3Ozzkiy9KBS+AMrVw5W33IElOdQzH82BLjPnNE3Yl3ybotoTcqkSds4vQaaF SUaaveMPkSPFiMKFo8UcTzEI93z7IG14pmOokWlv0q4qHWTtUT0qGyAcNReUEGiNIPJe Kx+Hysw0+8Q/GlXyI3ExbhKbaL/X/yjjCysbLkKc33b6UsrIdA9sp3HKMUgOoeuwomwn iKj686m6zaAVFwYY9hIR18NXTjtdNBCp5q9ExCzZl97Fv6AWKj6oQ/4FOFKoIOd4so5J PZSQ== X-Gm-Message-State: AOAM533aiayKZ5xTmobjFflkCRfz03qhFohFcu7QqCnNkgQzjSekVtyF iFwoAkxZyusj8TFzTVWjI6m8FOhy6BVwaPGzd3UVh51mmaMvciJBXEEdjK3Mul92glTnv2huy4j NwYnorxkskiyEk6KnpGvMEwLLD+0VjwEZcHSjLBaFM4aO5n3WoKsM1kZGuZqB X-Received: by 2002:a05:6000:1002:: with SMTP id a2mr4282113wrx.501.1641553483370; Fri, 07 Jan 2022 03:04:43 -0800 (PST) X-Google-Smtp-Source: ABdhPJyidQzH+XJ35C0heg3oKG7uTqtYjFBlwa1atKvBNMCzOEKYFB5D24yDb3KC3Ki+U0gw8RdcNg== X-Received: by 2002:a05:6000:1002:: with SMTP id a2mr4282095wrx.501.1641553483184; Fri, 07 Jan 2022 03:04:43 -0800 (PST) Received: from redhat.com ([2.55.16.192]) by smtp.gmail.com with ESMTPSA id q6sm4426000wrr.88.2022.01.07.03.04.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Jan 2022 03:04:42 -0800 (PST) Date: Fri, 7 Jan 2022 06:04:40 -0500 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Subject: [PULL v2 32/55] util/oslib-posix: Don't create too many threads with small memory or little pages Message-ID: <20220107102526.39238-33-mst@redhat.com> References: <20220107102526.39238-1-mst@redhat.com> MIME-Version: 1.0 In-Reply-To: <20220107102526.39238-1-mst@redhat.com> X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mst@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.372, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Daniel P =?utf-8?B?LiBCZXJyYW5nw6k=?= , David Hildenbrand , Michal Privoznik , Pankaj Gupta , "Dr . David Alan Gilbert" , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: David Hildenbrand Let's limit the number of threads to something sane, especially that - We don't have more threads than the number of pages we have - We don't have threads that initialize small (< 64 MiB) memory Reviewed-by: Pankaj Gupta Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Daniel P. Berrangé Reviewed-by: Michal Privoznik Signed-off-by: David Hildenbrand Message-Id: <20211217134611.31172-5-david@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- util/oslib-posix.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/util/oslib-posix.c b/util/oslib-posix.c index cf2ead54ad..67c08a425e 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -40,6 +40,7 @@ #include #include "qemu/cutils.h" #include "qemu/compiler.h" +#include "qemu/units.h" #ifdef CONFIG_LINUX #include @@ -525,7 +526,8 @@ static void *do_madv_populate_write_pages(void *arg) return (void *)(uintptr_t)ret; } -static inline int get_memset_num_threads(int smp_cpus) +static inline int get_memset_num_threads(size_t hpagesize, size_t numpages, + int smp_cpus) { long host_procs = sysconf(_SC_NPROCESSORS_ONLN); int ret = 1; @@ -533,6 +535,12 @@ static inline int get_memset_num_threads(int smp_cpus) if (host_procs > 0) { ret = MIN(MIN(host_procs, MAX_MEM_PREALLOC_THREAD_COUNT), smp_cpus); } + + /* Especially with gigantic pages, don't create more threads than pages. */ + ret = MIN(ret, numpages); + /* Don't start threads to prealloc comparatively little memory. */ + ret = MIN(ret, MAX(1, hpagesize * numpages / (64 * MiB))); + /* In case sysconf() fails, we fall back to single threaded */ return ret; } @@ -542,7 +550,7 @@ static int touch_all_pages(char *area, size_t hpagesize, size_t numpages, { static gsize initialized = 0; MemsetContext context = { - .num_threads = get_memset_num_threads(smp_cpus), + .num_threads = get_memset_num_threads(hpagesize, numpages, smp_cpus), }; size_t numpages_per_thread, leftover; void *(*touch_fn)(void *); -- MST