Message-ID: <5267F4CA.3070106@linux.vnet.ibm.com>
Date: Wed, 23 Oct 2013 21:39:46 +0530
From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
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To: Johannes Weiner <hannes@cmpxchg.org>
CC: akpm@linux-foundation.org, mgorman@suse.de, dave@sr71.net,
        tony.luck@intel.com, matthew.garrett@nebula.com, riel@redhat.com,
        arjan@linux.intel.com, srinivas.pandruvada@linux.intel.com,
        willy@linux.intel.com, kamezawa.hiroyu@jp.fujitsu.com, lenb@kernel.org,
        rjw@sisk.pl, gargankita@gmail.com, paulmck@linux.vnet.ibm.com,
        svaidy@linux.vnet.ibm.com, andi@firstfloor.org,
        isimatu.yasuaki@jp.fujitsu.com, santosh.shilimkar@ti.com,
        kosaki.motohiro@gmail.com, linux-pm@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org, mark.gross@intel.com
Subject: Re: [RFC PATCH v4 06/40] mm: Demarcate and maintain pageblocks in
 region-order in the zones' freelists
References: <20130925231250.26184.31438.stgit@srivatsabhat.in.ibm.com> <20130925231454.26184.19783.stgit@srivatsabhat.in.ibm.com> <20131023101703.GC2043@cmpxchg.org>
In-Reply-To: <20131023101703.GC2043@cmpxchg.org>
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On 10/23/2013 03:47 PM, Johannes Weiner wrote:
> On Thu, Sep 26, 2013 at 04:44:56AM +0530, Srivatsa S. Bhat wrote:
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -517,6 +517,111 @@ static inline int page_is_buddy(struct page *page, struct page *buddy,
>>  	return 0;
>>  }
>>  
>> +static void add_to_freelist(struct page *page, struct free_list *free_list)
>> +{
>> +	struct list_head *prev_region_list, *lru;
>> +	struct mem_region_list *region;
>> +	int region_id, i;
>> +
>> +	lru = &page->lru;
>> +	region_id = page_zone_region_id(page);
>> +
>> +	region = &free_list->mr_list[region_id];
>> +	region->nr_free++;
>> +
>> +	if (region->page_block) {
>> +		list_add_tail(lru, region->page_block);
>> +		return;
>> +	}
>> +
>> +#ifdef CONFIG_DEBUG_PAGEALLOC
>> +	WARN(region->nr_free != 1, "%s: nr_free is not unity\n", __func__);
>> +#endif
>> +
>> +	if (!list_empty(&free_list->list)) {
>> +		for (i = region_id - 1; i >= 0; i--) {
>> +			if (free_list->mr_list[i].page_block) {
>> +				prev_region_list =
>> +					free_list->mr_list[i].page_block;
>> +				goto out;
>> +			}
>> +		}
>> +	}
>> +
>> +	/* This is the first region, so add to the head of the list */
>> +	prev_region_list = &free_list->list;
>> +
>> +out:
>> +	list_add(lru, prev_region_list);
>> +
>> +	/* Save pointer to page block of this region */
>> +	region->page_block = lru;
> 
> "Pageblock" has a different meaning in the allocator already.
> 
> The things you string up here are just called pages, regardless of
> which order they are in and how many pages they can be split into.
> 

Ah, yes. I'll fix that.

Regards,
Srivatsa S. Bhat

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