Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161200AbbENWJj (ORCPT ); Thu, 14 May 2015 18:09:39 -0400 Received: from fn.samba.org ([216.83.154.106]:58093 "EHLO mail.samba.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161109AbbENWJf (ORCPT ); Thu, 14 May 2015 18:09:35 -0400 Date: Thu, 14 May 2015 15:09:32 -0700 From: Jeremy Allison To: Linus Torvalds Cc: Al Viro , Linux Kernel Mailing List , linux-fsdevel , Christoph Hellwig , Neil Brown Subject: Re: [RFC][PATCHSET v3] non-recursive pathname resolution & RCU symlinks Message-ID: <20150514220932.GC31808@samba2> Reply-To: Jeremy Allison References: <20150505052205.GS889@ZenIV.linux.org.uk> <20150511180650.GA4147@ZenIV.linux.org.uk> <20150513222533.GA24192@ZenIV.linux.org.uk> <20150514033040.GF7232@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1648 Lines: 35 On Wed, May 13, 2015 at 08:52:59PM -0700, Linus Torvalds wrote: > On Wed, May 13, 2015 at 8:30 PM, Al Viro wrote: > > > > Maybe... I'd like to see the profiles, TBH - especially getxattr() and > > access() frequency on various loads. Sure, make(1) and cc(1) really care > > about stat() very much, but I wouldn't be surprised if something like > > httpd or samba would be hitting getxattr() a lot... > > So I haven't seen samba profiles in ages, but iirc we have more > serious problems than trying to speed up basic filename lookup. Let me know what you need :-). > > Also, I *think* samba ends up basically doing most of the pathname > lookups from its own user-level cache, because of how it needs to > avoid symlinks and do the whole crazy case insensitive pathname thing. > I have this very dim memory that that's one reason samba ends up being > so readdir-intensive. But I might be wrong, it's been many years since > I talked to anybody about samba, and I don't run it myself. You should, it's very good these days :-). We have to walk the directory trees to do the case insensitive pathname lookups, but we cache these so when we get an incoming pathname we look it up in the cache, see if we can stat the looked up name and if so we're done with pathname resolution. Of course we tell people to just set their filesystems up using mkfs.xfs -n version=ci :-). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/