Re: [PATCH] 2/2 Prezeroing large blocks of pages during allocation
From: Mel Gorman (mel_at_csn.ul.ie)
Date: 02/28/05
- Previous message: Andrea Arcangeli: "Re: two pipe bugfixes"
- In reply to: Dave Hansen: "Re: [PATCH] 2/2 Prezeroing large blocks of pages during allocation"
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Date: Mon, 28 Feb 2005 19:01:53 +0000 (GMT) To: Dave Hansen <haveblue@us.ibm.com>
On Mon, 28 Feb 2005, Dave Hansen wrote:
> On Sun, 2005-02-27 at 13:43 +0000, Mel Gorman wrote:
> > + /*
> > + * If this is a request for a zero page and the page was
> > + * not taken from the USERZERO pool, zero it all
> > + */
> > + if ((flags & __GFP_ZERO) && alloctype != ALLOC_USERZERO) {
> > + int zero_order=order;
> > +
> > + /*
> > + * This is important. We are about to zero a block
> > + * which may be larger than we need so we have to
> > + * determine do we zero just what we need or do
> > + * we zero the whole block and put the pages in
> > + * the zero page.
> > + *
> > + * We zero the whole block in the event we are taking
> > + * from the KERNNORCLM pools and otherwise zero just
> > + * what we need. The reason we do not always zero
> > + * everything is because we do not want unreclaimable
> > + * pages to leak into the USERRCLM and KERNRCLM
> > + * pools
> > + *
> > + */
> > + if (alloctype != ALLOC_USERRCLM &&
> > + alloctype != ALLOC_KERNRCLM) {
> > + area = zone->free_area_lists[ALLOC_USERZERO] +
> > + current_order;
> > + zero_order = current_order;
> > + }
> > +
> > +
> > + spin_unlock_irqrestore(&zone->lock, *irq_flags);
> > + prep_zero_page(page, zero_order, flags);
> > + inc_zeroblock_count(zone, zero_order, flags);
> > + spin_lock_irqsave(&zone->lock, *irq_flags);
> > +
> > + }
> > +
> > return expand(zone, page, order, current_order, area);
> > }
> >
>
> I think it would make sense to put that in its own helper function.
> When comments get that big, they often reduce readability. The only
> outside variable that gets modified is "area", I think.
>
> So, a static inline:
>
> area = my_new_function_with_the_huge_comment(zone, ..., area);
>
Will make that change in the next version. It makes perfect sense.
> BTW, what kernel does this apply against? Is linux-2.6.11-rc4-v18 the
> same as bk18?
>
It applies on top of 2.6.11-rc4 with the latest version of the placement
policy. Admittedly, the naming of the tree is not very obvious.
-- Mel Gorman - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
- Previous message: Andrea Arcangeli: "Re: two pipe bugfixes"
- In reply to: Dave Hansen: "Re: [PATCH] 2/2 Prezeroing large blocks of pages during allocation"
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