linux-kernel - Re: [PATCH] zswap: Same-filled pages handling

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Date:   Wed, 18 Oct 2017 18:08:41 -0700
From:   Matthew Wilcox <willy@...radead.org>
To:     Timofey Titovets <nefelim4ag@...il.com>
Cc:     Srividya Desireddy <srividya.dr@...sung.com>,
        "sjenning@...hat.com" <sjenning@...hat.com>,
        "ddstreet@...e.org" <ddstreet@...e.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "penberg@...nel.org" <penberg@...nel.org>,
        Dinakar Reddy Pathireddy <dinakar.p@...sung.com>,
        SHARAN ALLUR <sharan.allur@...sung.com>,
        RAJIB BASU <rajib.basu@...sung.com>,
        JUHUN KIM <juhunkim@...sung.com>,
        "srividya.desireddy@...il.com" <srividya.desireddy@...il.com>
Subject: Re: [PATCH] zswap: Same-filled pages handling

On Thu, Oct 19, 2017 at 12:31:18AM +0300, Timofey Titovets wrote:
> > +static void zswap_fill_page(void *ptr, unsigned long value)
> > +{
> > +       unsigned int pos;
> > +       unsigned long *page;
> > +
> > +       page = (unsigned long *)ptr;
> > +       if (value == 0)
> > +               memset(page, 0, PAGE_SIZE);
> > +       else {
> > +               for (pos = 0; pos < PAGE_SIZE / sizeof(*page); pos++)
> > +                       page[pos] = value;
> > +       }
> > +}
> 
> Same here, but with memcpy().

No.  Use memset_l which is optimised for this specific job.