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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 39260C433EF for ; Tue, 14 Jun 2022 14:38:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237013AbiFNOiH (ORCPT ); Tue, 14 Jun 2022 10:38:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238292AbiFNOiE (ORCPT ); Tue, 14 Jun 2022 10:38:04 -0400 Received: from mail-wr1-x433.google.com (mail-wr1-x433.google.com [IPv6:2a00:1450:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 934EEB7F2 for ; Tue, 14 Jun 2022 07:38:01 -0700 (PDT) Received: by mail-wr1-x433.google.com with SMTP id u8so11544860wrm.13 for ; Tue, 14 Jun 2022 07:38:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=rLp+y2Cb7SGsOa4Obd9vWUi02TdIW1M+K1OPPdobolA=; b=Mn8Ky7Jy4loDj5LXl+qEPXExYO+fdvaUxAMaXVRKjDtsjtekmmgSLcZ8L9Shrxu816 oUDrxnK6GhEWy1Q6691s2cbW21MmJLhispCkfYty+R++jDZ9NarZUXbdYDIynTdo9moc V4mTSB+JQLmWpOpnWFryk0pGlbop0gW1OeeGUWLvRalUivctYrd40i+PMaZ+7mfWdC33 85bamVg34HD8m04I9GcbPjGfOcHIwx90dXGGCN2xdsUTc6DzbsH464xvbT/vrriCNKC2 GQvWsFCndEDXskpXqAAzlrAOA83gmKkPaTw014+EIRslB4QDbJgbkZcICwZRVHMw2TzS HlZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=rLp+y2Cb7SGsOa4Obd9vWUi02TdIW1M+K1OPPdobolA=; b=rZNfQnhgOyFyTUd0jEdk7++f+40EUTXASpvKZLFwosSGFuTqPlOo5i6kZ7ICLDOnHQ O8drfAgoxbqf2yrPfxAbbRUXyuZHMJbeld7/WlQv3qCgBbpjip+Eu4BS9KaOQK80nmlP KpfJyHvTVWFrAtVcbJbec66tUkt3AB6UFrLgcy1oFXRUBznrTmOFDqn8HLr4zFlq6VAU OictliRgcV4BiraRyNpJfh+EMK1zOYIEo2ZOrlCPkGjhXricGzKzaaZBJTTFb6fI0+Z6 IBYwwBKoYuNXESCE/ICsgQ/Xt3FJztWpaffzdRHjnI0Qu8LNs2cc2tSAEB/tKT0ymEYZ CL9w== X-Gm-Message-State: AJIora+IxBBS5MBwv8pSzB6AeIiVdvKHn8tek6mAly5zrc1fckpETY5x 4m8F/PjKd52dc5lbu+R5IJYvk4d+HR4eBQ== X-Google-Smtp-Source: AGRyM1v77VP+8Peb3biaoWVo6lzSoqPJlKccOfowZVRMskAUw+z7U1tAnzJKUz4+GJeT5q69WcbtbA== X-Received: by 2002:a5d:55ca:0:b0:211:4092:1c27 with SMTP id i10-20020a5d55ca000000b0021140921c27mr5405759wrw.108.1655217479849; Tue, 14 Jun 2022 07:37:59 -0700 (PDT) Received: from 127.0.0.1localhost (188.28.125.106.threembb.co.uk. [188.28.125.106]) by smtp.gmail.com with ESMTPSA id a4-20020adff7c4000000b0021033caa332sm12353064wrq.42.2022.06.14.07.37.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jun 2022 07:37:59 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [PATCH for-next v2 18/25] io_uring: limit number hash buckets Date: Tue, 14 Jun 2022 15:37:08 +0100 Message-Id: <57a30f28ac6235d7913444ff3bee9bc5ce70f5d4.1655213915.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Don't allocate to many hash/cancellation buckets, there might be too many, clamp it to 8 bits, or 256 * 64B = 16KB. We don't usually have too many requests, and 256 buckets should be enough, especially since we do hash search only in the cancellation path. Signed-off-by: Pavel Begunkov --- io_uring/io_uring.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 4d94757e6e28..2a7a5db12a0e 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -710,12 +710,12 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) /* * Use 5 bits less than the max cq entries, that should give us around - * 32 entries per hash list if totally full and uniformly spread. + * 32 entries per hash list if totally full and uniformly spread, but + * don't keep too many buckets to not overconsume memory. */ - hash_bits = ilog2(p->cq_entries); - hash_bits -= 5; - if (hash_bits <= 0) - hash_bits = 1; + hash_bits = ilog2(p->cq_entries) - 5; + hash_bits = clamp(hash_bits, 1, 8); + ctx->cancel_hash_bits = hash_bits; ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct io_hash_bucket), -- 2.36.1