From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 28 Feb 2005 19:01:53 +0000 (GMT) From: Mel Gorman Subject: Re: [PATCH] 2/2 Prezeroing large blocks of pages during allocation In-Reply-To: <1109609180.6921.22.camel@localhost> Message-ID: References: <20050227134316.2D0F1ECE4@skynet.csn.ul.ie> <1109609180.6921.22.camel@localhost> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: linux-mm , Linux Kernel Mailing List , clameter@sgi.com List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org