linux-kernel - Re: [PATCH] Properly account for freed pages in free_pages_bulk() and when allocating high-order pages in buffered

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.64.0904281810240.30878@blonde.anvils>
Date:	Tue, 28 Apr 2009 18:15:30 +0100 (BST)
From:	Hugh Dickins <hugh@...itas.com>
To:	Mel Gorman <mel@....ul.ie>
cc:	Christoph Lameter <cl@...ux.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Memory Management List <linux-mm@...ck.org>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Nick Piggin <npiggin@...e.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Lin Ming <ming.m.lin@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Pekka Enberg <penberg@...helsinki.fi>,
	"Zhang, Yanmin" <yanmin_zhang@...ux.intel.com>
Subject: Re: [PATCH] Properly account for freed pages in free_pages_bulk()
 and when allocating high-order pages in buffered_rmqueue()

On Tue, 28 Apr 2009, Mel Gorman wrote:
> On Tue, Apr 28, 2009 at 12:37:22PM -0400, Christoph Lameter wrote:
> > On Tue, 28 Apr 2009, Mel Gorman wrote:
> > 
> > > @@ -1151,6 +1151,7 @@ again:
> > >  	} else {
> > >  		spin_lock_irqsave(&zone->lock, flags);
> > >  		page = __rmqueue(zone, order, migratetype);
> > > +		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order));
> > >  		spin_unlock(&zone->lock);
> > >  		if (!page)
> > >  			goto failed;
> > 
> > __mod_zone_page_state takes an signed integer argument. Not sure what is
> > won by the UL suffix here.
> > 
> 
> Matches other call sites such as in __offline_isolated_pages(), habit when
> using shifts like this and matches other locations, paranoia, doesn't hurt.

Well, not a big deal, but I'd say that it does hurt: by wasting people's
time (mine!), wondering what that "UL" is for - I'd have had to ask, if
Christoph hadn't cleared this up first (thank you).  And elsewhere,
you're using an int << order to update NR_FREE_PAGES, so I don't see
the consistency argument.

Hugh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/