linux-kernel - Re: [PATCH] mm, kmemleak: Little optimization while scanning

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Date:   Fri, 07 Dec 2018 07:14:10 +0100
From:   Oscar Salvador <osalvador@...e.de>
To:     Wei Yang <richard.weiyang@...il.com>
Cc:     akpm@...ux-foundation.org, catalin.marinas@....com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org, mhocko@...e.com
Subject: Re: [PATCH] mm, kmemleak: Little optimization while scanning


> > +
> 
> This one maybe not necessary.

Yeah, that is a remind of an include file I used for time measurement.
I hope Andrew can drop that if this is taken.

> > /*
> >  * Kmemleak configuration and common defines.
> >  */
> > @@ -1547,11 +1548,14 @@ static void kmemleak_scan(void)
> > 		unsigned long pfn;
> > 
> > 		for (pfn = start_pfn; pfn < end_pfn; pfn++) {
> > -			struct page *page;
> > +			struct page *page =
> > pfn_to_online_page(pfn);
> > +
> > +			if (!page)
> > +				continue;
> > 
> > -			if (!pfn_valid(pfn))
> > +			/* only scan pages belonging to this node
> > */
> > +			if (page_to_nid(page) != i)
> > 				continue;
> 
> Not farmiliar with this situation. Is this often?
Well, hard to tell how often that happens because that mostly depends
on the Hardware in case of baremetal.
Virtual systems can also have it though.

> 
> > -			page = pfn_to_page(pfn);
> > 			/* only scan if page is in use */
> > 			if (page_count(page) == 0)
> > 				continue;
> > -- 
> > 2.13.7
> 
> 
-- 
Oscar Salvador
SUSE L3