From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <libc-alpha-return-105162-e=80x24.org@sourceware.org>
X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net
X-Spam-Level: 
X-Spam-ASN: AS31976 209.132.180.0/23
X-Spam-Status: No, score=-4.1 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS
	shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2
Received: from sourceware.org (server1.sourceware.org [209.132.180.131])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by dcvr.yhbt.net (Postfix) with ESMTPS id CA3011F463
	for <e@80x24.org>; Thu, 12 Sep 2019 01:04:07 +0000 (UTC)
DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:from:to:cc:subject:in-reply-to:date:message-id
	:mime-version:content-type; q=dns; s=default; b=Nd4rm1OlEXF29eIi
	8JwWaRTh7h8h41TrhFm60LRP6sP2HW37s0gnxsH0PgStkRmrJ8P2kRyRSMEvU0uy
	Q5WqV0JPb6O4ZWydyXCGqj7W52iAtr/vylD5avn9zU5U0cAeJDi4bgn/K+OkSuTX
	nAuMBffmgcWlnPQ45afz3CJYICk=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:from:to:cc:subject:in-reply-to:date:message-id
	:mime-version:content-type; s=default; bh=0KqvaYoWAvTayZLyoEXwFl
	wF8iU=; b=rJGhF6giClPoBqqlv0uxjnPCl27TZr1kwUoCAzzqR5lCCdG4pfcNEM
	xzUd1d9SSwjNBxqO+Lgga5OzoZXfL1BzHZQzgIVsbdhl6iCZx0q5yxPICsPrHnQC
	9N5E51v05CdD/tgfMETJUjKrYRRWcVug3aAM2nBjTZjY+klL7sLGw=
Received: (qmail 51853 invoked by alias); 12 Sep 2019 01:04:04 -0000
Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <libc-alpha.sourceware.org>
List-Unsubscribe: <mailto:libc-alpha-unsubscribe-e=80x24.org@sourceware.org>
List-Subscribe: <mailto:libc-alpha-subscribe@sourceware.org>
List-Archive: <http://sourceware.org/ml/libc-alpha/>
List-Post: <mailto:libc-alpha@sourceware.org>
List-Help: <mailto:libc-alpha-help@sourceware.org>, <http://sourceware.org/ml/#faqs>
Sender: libc-alpha-owner@sourceware.org
Received: (qmail 51845 invoked by uid 89); 12 Sep 2019 01:04:03 -0000
Authentication-Results: sourceware.org; auth=none
X-HELO: mx1.redhat.com
From: DJ Delorie <dj@redhat.com>
To: Isaku Yamahata <isaku.yamahata@gmail.com>
Cc: libc-alpha@sourceware.org
Subject: Re: [RFC PATCH 07/11] malloc: make arena size configurable on startup
In-Reply-To: <0438c6b3f81ee46abef884de161dbb4b624655db.1568219400.git.isaku.yamahata@gmail.com> (message from Isaku Yamahata on Wed, 11 Sep 2019 14:04:05 -0700)
Date: Wed, 11 Sep 2019 21:03:59 -0400
Message-ID: <xn7e6eiav4.fsf@greed.delorie.com>
MIME-Version: 1.0
Content-Type: text/plain


I have no fundamental problem with tuning the heap size, but...

1. The heap size must always be a power of two; you need to enforce that
   in the tunable callback.

2. Do you have any benchmarks that show that these changes don't affect
   performance?  I don't mean differing size heaps, I mean changing a
   constant to a variable in the code.

3. I don't see the point of heap_max_specified.