From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933073AbeB1TFG (ORCPT ); Wed, 28 Feb 2018 14:05:06 -0500 Received: from mail-pl0-f65.google.com ([209.85.160.65]:47046 "EHLO mail-pl0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932088AbeB1TFE (ORCPT ); Wed, 28 Feb 2018 14:05:04 -0500 X-Google-Smtp-Source: AH8x225QcYXbyJEAcDmPp/Xjd9WzBfe2QGHsvuwvB7hTMnfDv2IdVwdLe4TD4YUVfBw2Yf5NTgKM2w== From: frowand.list@gmail.com To: Rob Herring , cpandya@codeaurora.org Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 0/2] of: cache phandle nodes to reduce cost of of_find_node_by_phandle() Date: Wed, 28 Feb 2018 11:04:14 -0800 Message-Id: <1519844656-16443-1-git-send-email-frowand.list@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Frank Rowand Create a cache of the nodes that contain a phandle property. Use this cache to find the node for a given phandle value instead of scanning the devicetree to find the node. If the phandle value is not found in the cache, of_find_node_by_phandle() will fall back to the tree scan algorithm. Size and performance data is in patch 1/2 comments Changes since v3: - of_populate_phandle_cache(): add check for failed memory allocation - add patch 2/2 into series instead of as a standalone patch that was dependent on patch 1/2 of this series Changes since v2: - add mask to calculation of phandle cache entry - which results in better overhead reduction for devicetrees with phandle properties not allocated in the monotonically increasing range of 1..n - due to mask, number of entries in cache potentially increased to next power of two - minor fixes as suggested by reviewers - no longer using live_tree_max_phandle() so do not move it from drivers/of/resolver.c to drivers/of/base.c Changes since v1: - change short description from of: cache phandle nodes to reduce cost of of_find_node_by_phandle() - rebase on v4.16-rc1 - reorder new functions in base.c to avoid forward declaration - add locking around kfree(phandle_cache) for memory ordering - add explicit check for non-null of phandle_cache in of_find_node_by_phandle(). There is already a check for !handle, which prevents accessing a null phandle_cache, but that dependency is not obvious, so this check makes it more apparent. - do not free phandle_cache if modules are enabled, so that cached phandles will be available when modules are loaded Frank Rowand (2): of: cache phandle nodes to reduce cost of of_find_node_by_phandle() of: add early boot allocation of of_find_node_by_phandle() cache drivers/of/base.c | 119 ++++++++++++++++++++++++++++++++++++++++++++++-- drivers/of/fdt.c | 2 + drivers/of/of_private.h | 5 ++ drivers/of/resolver.c | 3 -- 4 files changed, 122 insertions(+), 7 deletions(-) -- Frank Rowand