From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: * X-Spam-Status: No, score=1.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_SOFTFAIL autolearn=no autolearn_force=no version=3.4.6 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E60FCCA47D for ; Thu, 16 Jun 2022 09:22:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376331AbiFPJW4 (ORCPT ); Thu, 16 Jun 2022 05:22:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376481AbiFPJWy (ORCPT ); Thu, 16 Jun 2022 05:22:54 -0400 Received: from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com [IPv6:2a00:1450:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7749B11174 for ; Thu, 16 Jun 2022 02:22:53 -0700 (PDT) Received: by mail-wr1-x42b.google.com with SMTP id s1so1035718wra.9 for ; Thu, 16 Jun 2022 02:22:53 -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=fb6MpG+TUR+lfc/l0HsFy1uGwvkTzMYMEuxuESOhYE4=; b=HrvVHvyie15H815z2sNl4TYkIdl/No+fxC/1/XFc3hlf6Yo/sNS0K7guQ+3JtGQ4ly fo7PT5J8o1BUdR+SC2LMvBc5N4+1LvdVGHHTh+Qkxj0iEXqKXXTIYbePhyUBCk/K8q5R /WN+k19jJht4AYhzrzLexgnCjBaRK6A8CK3ruP7xkHRc251tOMHsZetd2iAyK7biVYb5 jVdUlZXNEllhZlhLfS5rEtAjvaqi6FBhY3YgE4k4xrMCwChJg82fGoQZtY/JvNXaK1Rm V1l1NVm/IQNRfiJTUUPOJyVK5SRi1BSlSpaMvcO9KR2cdJ4tXV395W/lwIS2FhxZ3kUK FOMg== 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=fb6MpG+TUR+lfc/l0HsFy1uGwvkTzMYMEuxuESOhYE4=; b=PwaRnlnCb/ZFdn2JITRC4PmGU9J5TkRdUEFb3ndWqdHuxJ+sASoDD2M9mB0tcbwMv8 lwJSYYPeFkLksNmr/s9zb6pMi6VjMnIctyo6yS1EoZ/ODkvZ3hckuj5PK5R+iyq70PZj b6DzD6ALCPxNT68T4SW2PXBEJYOMHhZNXzsDAhftrfccnZ5EjhMDv5AiV2xSS7rqP2AJ IbbljO1Y9LTV3V+rqhaVx/X87U98Ok/J7Wwtn+HKFtkUQAAUsyjKNDuQIAV1b1ESoUT5 1dgYLgjUhke24Pw5hUgJqZi6yPczEJbwLMV+1HnV+bOFwRHRxQyvOTqPLPrabwVzQONZ mZnw== X-Gm-Message-State: AJIora8SIOXZdWvlekBBOiHf7NJVzPcrNpzxc2lrOjPr99UoDn5EkLAu Chf9HGN2f0xhTkJ26NdmNOEd/iE+1VjKEg== X-Google-Smtp-Source: AGRyM1uzuD58Gvw8ldCGsMjEj9bif5uM5n1mI+w4DxkZrCSYFjIOptjgJbeQYnZve+HKVZa2FPRdFw== X-Received: by 2002:a5d:6d0d:0:b0:218:45b1:ef1f with SMTP id e13-20020a5d6d0d000000b0021845b1ef1fmr3784547wrq.558.1655371372744; Thu, 16 Jun 2022 02:22:52 -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 s6-20020a1cf206000000b0039c975aa553sm1695221wmc.25.2022.06.16.02.22.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Jun 2022 02:22:52 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org Cc: Jens Axboe , asml.silence@gmail.com Subject: [PATCH for-next v3 09/16] io_uring: limit the number of cancellation buckets Date: Thu, 16 Jun 2022 10:22:05 +0100 Message-Id: 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 d0242e5c8d0a..97113c71e881 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -254,12 +254,12 @@ 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