linux-kernel - Re: [PATCH 0/5] mm: support parallel free of memory

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Date:   Wed, 1 Mar 2017 09:17:26 +0800
From:   Aaron Lu <aaron.lu@...el.com>
To:     Dave Hansen <dave.hansen@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Tim Chen <tim.c.chen@...el.com>,
        Ying Huang <ying.huang@...el.com>
Subject: Re: [PATCH 0/5] mm: support parallel free of memory

On 03/01/2017 08:43 AM, Dave Hansen wrote:
> On 02/28/2017 04:39 PM, Andrew Morton wrote:
>> Dumb question: why not do this in userspace, presumably as part of the
>> malloc() library?  malloc knows where all the memory is and should be
>> able to kick off N threads to run around munmapping everything?
> 
> One of the places we saw this happen was when an app crashed and was
> exit()'ing under duress without cleaning up nicely.  The time that it
> takes to unmap a few TB of 4k pages is pretty excessive.
 
Thanks Dave for the answer, I should have put this in the changelog(will
do that in the next revision). Sorry about this Andrew, I hope Dave's
answer clears things up about the patch's intention.

Regards,
Aaron