linux-kernel - Re: [v6 09/15] sparc64: optimized struct page zeroing

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Message-ID: <3830e513-cb35-e52e-341c-25eaecc51d43@oracle.com>
Date:   Fri, 11 Aug 2017 12:04:51 -0400
From:   Pasha Tatashin <pasha.tatashin@...cle.com>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     linux-kernel@...r.kernel.org, sparclinux@...r.kernel.org,
        linux-mm@...ck.org, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        x86@...nel.org, kasan-dev@...glegroups.com, borntraeger@...ibm.com,
        heiko.carstens@...ibm.com, davem@...emloft.net,
        willy@...radead.org, ard.biesheuvel@...aro.org,
        will.deacon@....com, catalin.marinas@....com, sam@...nborg.org
Subject: Re: [v6 09/15] sparc64: optimized struct page zeroing

>> Add an optimized mm_zero_struct_page(), so struct page's are zeroed without
>> calling memset(). We do eight to tent regular stores based on the size of
>> struct page. Compiler optimizes out the conditions of switch() statement.
> 
> Again, this doesn't explain why we need this. You have mentioned those
> reasons in some previous emails but be explicit here please.
> 

I will add performance data to this patch as well.

Thank you,
Pasha