linux-kernel - Re: [PATCH v10 09/10] mm: stop zeroing memory during allocation in vmemmap

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Message-ID: <20171006114729.fexwklupkhyxdpt3@dhcp22.suse.cz>
Date:   Fri, 6 Oct 2017 13:47:29 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     David Laight <David.Laight@...LAB.COM>
Cc:     'Pavel Tatashin' <pasha.tatashin@...cle.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "sparclinux@...r.kernel.org" <sparclinux@...r.kernel.org>,
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Subject: Re: [PATCH v10 09/10] mm: stop zeroing memory during allocation in
 vmemmap

On Fri 06-10-17 11:10:14, David Laight wrote:
> From: Pavel Tatashin
> > Sent: 05 October 2017 22:11
> > vmemmap_alloc_block() will no longer zero the block, so zero memory
> > at its call sites for everything except struct pages.  Struct page memory
> > is zero'd by struct page initialization.
> 
> It seems dangerous to change an allocator to stop zeroing memory.
> It is probably saver to add a new function that doesn't zero
> the memory and use that is the places where you don't want it
> to be zeroed.

Not sure what you mean. memblock_virt_alloc_try_nid_raw is a new
function which doesn't zero out...
-- 
Michal Hocko
SUSE Labs