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Subject: Re: [PATCH RFCv2] mm/madvise: introduce MADV_POPULATE_(READ|WRITE) to
 prefault/prealloc memory
To:     "Kirill A. Shutemov" <kirill@shutemov.name>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Arnd Bergmann <arnd@arndb.de>, Michal Hocko <mhocko@suse.com>,
        Oscar Salvador <osalvador@suse.de>,
        Matthew Wilcox <willy@infradead.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Minchan Kim <minchan@kernel.org>, Jann Horn <jannh@google.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Dave Hansen <dave.hansen@intel.com>,
        Hugh Dickins <hughd@google.com>,
        Rik van Riel <riel@surriel.com>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Richard Henderson <rth@twiddle.net>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
        Helge Deller <deller@gmx.de>, Chris Zankel <chris@zankel.net>,
        Max Filippov <jcmvbkbc@gmail.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Peter Xu <peterx@redhat.com>,
        Rolf Eike Beer <eike-kernel@sf-tec.de>,
        linux-alpha@vger.kernel.org, linux-mips@vger.kernel.org,
        linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org,
        linux-arch@vger.kernel.org, Linux API <linux-api@vger.kernel.org>
References: <20210308164520.18323-1-david@redhat.com>
 <20210315122213.k52wtlbbhsw42pks@box>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <7d607d1c-efd5-3888-39bb-9e5f8bc08185@redhat.com>
Date:   Mon, 15 Mar 2021 13:25:40 +0100
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On 15.03.21 13:22, Kirill A. Shutemov wrote:
> On Mon, Mar 08, 2021 at 05:45:20PM +0100, David Hildenbrand wrote:
>> +			case -EHWPOISON: /* Skip over any poisoned pages. */
>> +				start += PAGE_SIZE;
>> +				continue;
> 
> Why is it good approach? It's not abvious to me.

My main motivation was to simplify return code handling. I don't want to 
return -EHWPOISON to user space and I don't want to convert it into 
something misleading like -ENOMEM or -EINVAL. So I decided to handle 
such stuff internally.

What would be you take on that?

-- 
Thanks,

David / dhildenb