From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx121.postini.com [74.125.245.121]) by kanga.kvack.org (Postfix) with SMTP id 44FCE6B0062 for ; Thu, 2 Aug 2012 12:09:44 -0400 (EDT) From: ebiederm@xmission.com (Eric W. Biederman) References: <20120731182330.GD21292@google.com> <50197348.9010101@gmail.com> <20120801182112.GC15477@google.com> <50197460.8010906@gmail.com> <20120801182749.GD15477@google.com> <50197E4A.7020408@gmail.com> <20120801202432.GE15477@google.com> <5019B0B4.1090102@gmail.com> <20120801224556.GF15477@google.com> <501A4FC1.8040907@gmail.com> <20120802103244.GA23318@leaf> <501A633B.3010509@gmail.com> Date: Thu, 02 Aug 2012 09:03:49 -0700 In-Reply-To: <501A633B.3010509@gmail.com> (Sasha Levin's message of "Thu, 02 Aug 2012 13:23:39 +0200") Message-ID: <87txwl1dsq.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [RFC 1/4] hashtable: introduce a small and naive hashtable Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin Cc: Josh Triplett , Tejun Heo , torvalds@linux-foundation.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paul.gortmaker@windriver.com Sasha Levin writes: > On 08/02/2012 12:32 PM, Josh Triplett wrote: >> What about using a C99 flexible array member? Kernel style prohibits >> variable-length arrays, but I don't think the same rationale applies to >> flexible array members. >> >> struct hash_table { >> size_t count; >> struct hlist_head buckets[]; >> }; >> >> #define DEFINE_HASH_TABLE(name, length) struct hash_table name = { .count = length, .buckets = { [0 ... (length - 1)] = HLIST_HEAD_INIT } } > > The limitation of this approach is that the struct hash_table variable > must be 'static', which is a bit limiting - see for example the use of > hashtable in 'struct user_namespace'. You mean the hash table that was made static in 3.5? You might want to try basing your patches on something a little more current. Eric -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753670Ab2HBQJr (ORCPT ); Thu, 2 Aug 2012 12:09:47 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:37748 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753027Ab2HBQJo (ORCPT ); Thu, 2 Aug 2012 12:09:44 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Sasha Levin Cc: Josh Triplett , Tejun Heo , torvalds@linux-foundation.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, paul.gortmaker@windriver.com References: <20120731182330.GD21292@google.com> <50197348.9010101@gmail.com> <20120801182112.GC15477@google.com> <50197460.8010906@gmail.com> <20120801182749.GD15477@google.com> <50197E4A.7020408@gmail.com> <20120801202432.GE15477@google.com> <5019B0B4.1090102@gmail.com> <20120801224556.GF15477@google.com> <501A4FC1.8040907@gmail.com> <20120802103244.GA23318@leaf> <501A633B.3010509@gmail.com> Date: Thu, 02 Aug 2012 09:03:49 -0700 In-Reply-To: <501A633B.3010509@gmail.com> (Sasha Levin's message of "Thu, 02 Aug 2012 13:23:39 +0200") Message-ID: <87txwl1dsq.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=98.207.153.68;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19bpa1y4Pm9GqvaITw1S9uUaMsL24DP5Mo= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa01 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa01 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Sasha Levin X-Spam-Relay-Country: Subject: Re: [RFC 1/4] hashtable: introduce a small and naive hashtable X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Fri, 06 Aug 2010 16:31:04 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sasha Levin writes: > On 08/02/2012 12:32 PM, Josh Triplett wrote: >> What about using a C99 flexible array member? Kernel style prohibits >> variable-length arrays, but I don't think the same rationale applies to >> flexible array members. >> >> struct hash_table { >> size_t count; >> struct hlist_head buckets[]; >> }; >> >> #define DEFINE_HASH_TABLE(name, length) struct hash_table name = { .count = length, .buckets = { [0 ... (length - 1)] = HLIST_HEAD_INIT } } > > The limitation of this approach is that the struct hash_table variable > must be 'static', which is a bit limiting - see for example the use of > hashtable in 'struct user_namespace'. You mean the hash table that was made static in 3.5? You might want to try basing your patches on something a little more current. Eric