From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yinghai Subject: Re: [PATCH 18/39] lmb: Add lmb_reserve_area_overlap_ok() Date: Mon, 12 Apr 2010 21:44:56 -0700 Message-ID: <4BC3F6C8.4020303@oracle.com> References: <1270793048-23796-1-git-send-email-yinghai@kernel.org> <1270793048-23796-19-git-send-email-yinghai@kernel.org> <1271132476.13059.66.camel@pasglop> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from acsinet11.oracle.com ([141.146.126.233]:22894 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750733Ab0DMEry (ORCPT ); Tue, 13 Apr 2010 00:47:54 -0400 In-Reply-To: <1271132476.13059.66.camel@pasglop> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Benjamin Herrenschmidt Cc: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , Andrew Morton , David Miller , Linus Torvalds , Johannes Weiner , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org On 04/12/2010 09:21 PM, Benjamin Herrenschmidt wrote: > On Thu, 2010-04-08 at 23:03 -0700, Yinghai Lu wrote: >> Some areas from firmware could be reserved several times from different callers. >> >> If these area are overlapped, We may have overlapped entries in lmb.reserved. >> >> Try to free the area at first, before rerserve them again. >> >> Signed-off-by: Yinghai Lu >> --- > >> + >> +/* >> + * Could be used to avoid having overlap entries in lmb.reserved.region. >> + * Don't need to use it with area that is from lmb_find_area() >> + * Only use it for the area that fw hidden area. >> + */ >> +void __init lmb_reserve_area_overlap_ok(u64 start, u64 end, char *name) >> +{ >> + if (start == end) >> + return; >> + >> + if (WARN_ONCE(start > end, "lmb_reserve_area_overlap_ok: wrong range [%#llx, %#llx]\n", start, end)) >> + return; >> + >> + /* Free that region at first */ >> + lmb_free(start, end - start); >> + __lmb_reserve_area(start, end, name); >> } > > That is going to only work with one overlap. IE. lmb_free() will not do > very well unless it's a one and only match. > > You should modify it to work in a loop. that is only for some special cases about area that is reserved for fw region. and even there is overlapped area, it the code still can go through when lmb_to_bootmem or create range list for slab. because they are using range array subtract. > > Besides, lmb_reserve_area_overlap_ok() sucks as a name :-) any suggestion for better name? YH