From patchwork Fri Dec 7 06:30:33 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xin Long X-Patchwork-Id: 1009190 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="TjNvKDTg"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43B2fQ3PYlz9s55 for ; Fri, 7 Dec 2018 17:30:54 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726062AbeLGGax (ORCPT ); Fri, 7 Dec 2018 01:30:53 -0500 Received: from mail-pg1-f194.google.com ([209.85.215.194]:37131 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725978AbeLGGax (ORCPT ); Fri, 7 Dec 2018 01:30:53 -0500 Received: by mail-pg1-f194.google.com with SMTP id 80so1270458pge.4; Thu, 06 Dec 2018 22:30:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :in-reply-to:references; bh=IBqTyM54Tq10KxOqmHTX1iqosn8Fy5yMO6MBzN5sdao=; b=TjNvKDTg+yWV/bjny9Uceh9Tdqa/IH3OIyk2Nd65/VYhKJsojNbxVbmHnBk5P7s4Iw eVmVHZ/UIpQTJonA7NN1NVlmVCD3DidWgaLmA5lQXm+masoXl6Xe52mNjQTqqt5j5SgN SQQYzs0ibshmVutjm4LCHCCYIwhmtGlHxPr/1Voz5eaqPqFI/gJ8jXKDOckZE9P1IeYp FNB3tQiYIubfTD1q08PkdEhXfD9sfoJyARufL061XgbIBT8oASTm+3c0lm8VNSWu3il/ sCdzaG0Vb7N1lfj/PQZ+UOTkQ6bYi4mxtF70RZLiaFnvOFRvZiCM/eeVB0BkrKz3gUA9 6e5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:in-reply-to:references; bh=IBqTyM54Tq10KxOqmHTX1iqosn8Fy5yMO6MBzN5sdao=; b=stWTezFUQpnWxQY995nWl60/EJ9cqDr7oJ059s9rfjlEMWhtkEc/hVA6cggcRmTU9H 3cob5sWpsdbHfK3mU2q4Wq5WTeirPKDmfh/gNszFNBvXduenS1TLbT82leGvGVf6Vjsf trUnGFwNo+5NVoa6Rn2j/GYR/uF2Lob/9ChkuuNJreOvFx0nIXUghRsrmdk/CqGpubNZ ufAIkqEHtPzIazWZnUlXp+uM9m8UvzIhDRiGEfCmQmxdIum+XTaspDs1BBNuOiCycOsy T6Ui2QdMd95D0uCVu6/essDmyRKQXwSaOAHsm5onXmBR4qtT0p4KxBwgExelcG10Fpwi 4g5A== X-Gm-Message-State: AA+aEWZgAFfqxhVnkdmssxHyDxbIYhDKj4Hh7o9ptm+5uANaFGI3N3q7 cU4CyFW4WgTtcfUdJMFuIor3WmEDWCQ= X-Google-Smtp-Source: AFSGD/Ue5biVt5LzEzmCoSVjd5s1EGMP9I0OnyrAA45V6TEdzlGsgqqifBRtU7yl/Grm1nlV8lYecw== X-Received: by 2002:a63:7f4f:: with SMTP id p15mr909226pgn.296.1544164252017; Thu, 06 Dec 2018 22:30:52 -0800 (PST) Received: from localhost ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id o7sm2982928pfb.34.2018.12.06.22.30.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 06 Dec 2018 22:30:51 -0800 (PST) From: Xin Long To: linux-kernel@vger.kernel.org, network dev , linux-sctp@vger.kernel.org Cc: davem@davemloft.net, Marcelo Ricardo Leitner , Neil Horman , Dave Hansen , David Rientjes , Eric Paris , Konstantin Khorenko Subject: [PATCHv2 net 1/3] flex_array: make FLEX_ARRAY_BASE_SIZE the same value of FLEX_ARRAY_PART_SIZE Date: Fri, 7 Dec 2018 14:30:33 +0800 Message-Id: X-Mailer: git-send-email 2.1.0 In-Reply-To: References: In-Reply-To: References: Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch is to separate the base data memory from struct flex_array and save it into a page. With this change, total_nr_elements of a flex_array can grow or shrink without having the old element's memory changed when the new size of the flex_arry crosses FLEX_ARRAY_BASE_SIZE, which will be added in the next patch. Suggested-by: Neil Horman Signed-off-by: Xin Long Acked-by: Neil Horman --- include/linux/flex_array.h | 29 +++++++++-------------------- lib/flex_array.c | 15 ++++++++++++--- 2 files changed, 21 insertions(+), 23 deletions(-) diff --git a/include/linux/flex_array.h b/include/linux/flex_array.h index b94fa61..29ad65f 100644 --- a/include/linux/flex_array.h +++ b/include/linux/flex_array.h @@ -7,9 +7,10 @@ #include #define FLEX_ARRAY_PART_SIZE PAGE_SIZE -#define FLEX_ARRAY_BASE_SIZE PAGE_SIZE +#define FLEX_ARRAY_BASE_SIZE FLEX_ARRAY_PART_SIZE struct flex_array_part; +struct flex_array_part_p; /* * This is meant to replace cases where an array-like @@ -19,29 +20,17 @@ struct flex_array_part; */ struct flex_array { - union { - struct { - int element_size; - int total_nr_elements; - int elems_per_part; - struct reciprocal_value reciprocal_elems; - struct flex_array_part *parts[]; - }; - /* - * This little trick makes sure that - * sizeof(flex_array) == PAGE_SIZE - */ - char padding[FLEX_ARRAY_BASE_SIZE]; - }; + int element_size; + int total_nr_elements; + int elems_per_part; + struct reciprocal_value reciprocal_elems; + struct flex_array_part_p *part_p; +#define parts part_p->p_part }; -/* Number of bytes left in base struct flex_array, excluding metadata */ -#define FLEX_ARRAY_BASE_BYTES_LEFT \ - (FLEX_ARRAY_BASE_SIZE - offsetof(struct flex_array, parts)) - /* Number of pointers in base to struct flex_array_part pages */ #define FLEX_ARRAY_NR_BASE_PTRS \ - (FLEX_ARRAY_BASE_BYTES_LEFT / sizeof(struct flex_array_part *)) + (FLEX_ARRAY_BASE_SIZE / sizeof(struct flex_array_part *)) /* Number of elements of size that fit in struct flex_array_part */ #define FLEX_ARRAY_ELEMENTS_PER_PART(size) \ diff --git a/lib/flex_array.c b/lib/flex_array.c index 2eed22f..8c0b9b6 100644 --- a/lib/flex_array.c +++ b/lib/flex_array.c @@ -30,6 +30,10 @@ struct flex_array_part { char elements[FLEX_ARRAY_PART_SIZE]; }; +struct flex_array_part_p { + struct flex_array_part *p_part[FLEX_ARRAY_NR_BASE_PTRS]; +}; + /* * If a user requests an allocation which is small * enough, we may simply use the space in the @@ -39,7 +43,7 @@ struct flex_array_part { static inline int elements_fit_in_base(struct flex_array *fa) { int data_size = fa->element_size * fa->total_nr_elements; - if (data_size <= FLEX_ARRAY_BASE_BYTES_LEFT) + if (data_size <= FLEX_ARRAY_BASE_SIZE) return 1; return 0; } @@ -105,13 +109,17 @@ struct flex_array *flex_array_alloc(int element_size, unsigned int total, ret = kzalloc(sizeof(struct flex_array), flags); if (!ret) return NULL; + ret->part_p = kzalloc(sizeof(struct flex_array_part_p), flags); + if (!ret->part_p) { + kfree(ret); + return NULL; + } ret->element_size = element_size; ret->total_nr_elements = total; ret->elems_per_part = elems_per_part; ret->reciprocal_elems = reciprocal_elems; if (elements_fit_in_base(ret) && !(flags & __GFP_ZERO)) - memset(&ret->parts[0], FLEX_ARRAY_FREE, - FLEX_ARRAY_BASE_BYTES_LEFT); + memset(&ret->parts[0], FLEX_ARRAY_FREE, FLEX_ARRAY_BASE_SIZE); return ret; } EXPORT_SYMBOL(flex_array_alloc); @@ -148,6 +156,7 @@ EXPORT_SYMBOL(flex_array_free_parts); void flex_array_free(struct flex_array *fa) { flex_array_free_parts(fa); + kfree(fa->part_p); kfree(fa); } EXPORT_SYMBOL(flex_array_free);