From patchwork Mon Mar 27 20:11:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Snitzer X-Patchwork-Id: 13190060 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 E723AC6FD1D for ; Mon, 27 Mar 2023 20:14:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232200AbjC0UOW (ORCPT ); Mon, 27 Mar 2023 16:14:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232349AbjC0UOV (ORCPT ); Mon, 27 Mar 2023 16:14:21 -0400 Received: from mail-qt1-f178.google.com (mail-qt1-f178.google.com [209.85.160.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 857213583 for ; Mon, 27 Mar 2023 13:13:34 -0700 (PDT) Received: by mail-qt1-f178.google.com with SMTP id cr18so5982226qtb.0 for ; Mon, 27 Mar 2023 13:13:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679948013; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=P0nH8y5nrVQVdjQ+7MWEvssVfY/cEbcGbEWp6ylrqyQ=; b=ScdDx1DqN86Dz3YI124dbxilOBRwykvRhF62zEdEnm92B2AHG4TIeAV5UXI8ggN8jQ Y7+XDVq3idZljunFoh7WLJks+8dx6jy1QvNs+Evu06aik05yGPHc2ixN/5A9Mf1Jqdpp HBYYpswubxNAcCTFckCokxa+n2YvxdH1gmiV5ruP8/8blMEzJrQ70pJpZ6/QSDU8fFng qli1+oOOGrPTfB0BZsmrJXZWy0+REFvk3trDAmXmZr7sHbFi2/Ij80+ZoXIBJIGTXcc+ aoxHdyYtxo9sI3lN26R0n+1cGiByd4GN8kc36U6g2JcXUsOhfwkrEzlrnDjvmlEVfNOy 8Z5w== X-Gm-Message-State: AAQBX9eypFW929qszY+uxo/7XIj/tkYv43w/a/dxjRxTzdHOhVTzXG6l BHNbjjObJyg6VJhiF7wMTljp X-Google-Smtp-Source: AKy350Y96gqJ8gm1eUDkWBdhHVPSIF25C9Z/7pTPicBHvic+yBssV8gx7JTYQ5NQ4P/SYw+5vk3tRA== X-Received: by 2002:ac8:5c46:0:b0:3e4:e8a8:f235 with SMTP id j6-20020ac85c46000000b003e4e8a8f235mr8388241qtj.36.1679948013682; Mon, 27 Mar 2023 13:13:33 -0700 (PDT) Received: from localhost (pool-68-160-166-30.bstnma.fios.verizon.net. [68.160.166.30]) by smtp.gmail.com with ESMTPSA id 6-20020ac85646000000b003e3897d8505sm6400099qtt.54.2023.03.27.13.13.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Mar 2023 13:13:33 -0700 (PDT) From: Mike Snitzer To: dm-devel@redhat.com Cc: linux-block@vger.kernel.org, axboe@kernel.dk, ejt@redhat.com, mpatocka@redhat.com, heinzm@redhat.com, nhuck@google.com, ebiggers@kernel.org, keescook@chromium.org, luomeng12@huawei.com, Mike Snitzer Subject: [dm-6.4 PATCH v3 16/20] dm: add dm_num_sharded_locks() Date: Mon, 27 Mar 2023 16:11:39 -0400 Message-Id: <20230327201143.51026-17-snitzer@kernel.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230327201143.51026-1-snitzer@kernel.org> References: <20230327201143.51026-1-snitzer@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Simple helper to use when DM core code needs to appropriately size, based on num_online_cpus(), its data structures that split locks. dm_num_sharded_locks() rounds up num_online_cpus() to next power of 2 but caps return at DM_MAX_SHARDED_LOCKS (64). This heuristic may evolve as warranted, but as-is it will serve as a more informed basis for sizing the sharded lock structs in dm-bufio's dm_buffer_cache (buffer_trees) and dm-bio-prison-v1's dm_bio_prison (prison_regions). Signed-off-by: Mike Snitzer --- drivers/md/dm.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 22eaed188907..18450282d0d9 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -20,6 +20,7 @@ #include #include #include +#include #include "dm-stats.h" @@ -228,4 +229,13 @@ void dm_free_md_mempools(struct dm_md_mempools *pools); */ unsigned int dm_get_reserved_bio_based_ios(void); +#define DM_MAX_SHARDED_LOCKS 64 + +static inline unsigned int dm_num_sharded_locks(void) +{ + unsigned int num_locks = roundup_pow_of_two(num_online_cpus()); + + return min_t(unsigned int, num_locks, DM_MAX_SHARDED_LOCKS); +} + #endif