From: Minchan Kim <minchan@kernel.org>
To: Dave Hansen <dave@sr71.net>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, mgorman@suse.de,
tim.c.chen@linux.intel.com
Subject: Re: [v5][PATCH 5/6] mm: vmscan: batch shrink_page_list() locking operations
Date: Tue, 4 Jun 2013 15:59:30 +0900 [thread overview]
Message-ID: <20130604065930.GA26129@blaptop> (raw)
In-Reply-To: <51AD84BA.4090106@sr71.net>
On Mon, Jun 03, 2013 at 11:10:02PM -0700, Dave Hansen wrote:
> On 06/03/2013 10:01 PM, Minchan Kim wrote:
> >> > +static int __remove_mapping_batch(struct list_head *remove_list,
> >> > + struct list_head *ret_pages,
> >> > + struct list_head *free_pages)
> >> > +{
> >> > + int nr_reclaimed = 0;
> >> > + struct address_space *mapping;
> >> > + struct page *page;
> >> > + LIST_HEAD(need_free_mapping);
> >> > +
> >> > + while (!list_empty(remove_list)) {
> ...
> >> > + if (!__remove_mapping(mapping, page)) {
> >> > + unlock_page(page);
> >> > + list_add(&page->lru, ret_pages);
> >> > + continue;
> >> > + }
> >> > + list_add(&page->lru, &need_free_mapping);
> ...
> > + spin_unlock_irq(&mapping->tree_lock);
> > + while (!list_empty(&need_free_mapping)) {...
> > + list_move(&page->list, free_pages);
> > + mapping_release_page(mapping, page);
> > + }
> > Why do we need new lru list instead of using @free_pages?
>
> I actually tried using @free_pages at first. The problem is that we
> need to call mapping_release_page() without the radix tree lock held so
> we can not do it in the first while() loop.
>
> 'free_pages' is a list created up in shrink_page_list(). There can be
> several calls to __remove_mapping_batch() for each call to
> shrink_page_list().
I missed that point.
>
> 'need_free_mapping' lets us temporarily differentiate the pages that we
> need to call mapping_release_page()/unlock_page() on versus the ones on
> 'free_pages' which have already had that done.
>
Right.
> We could theoretically delay _all_ of the
> release_mapping_page()/unlock_page() operations until the _entire_
> shrink_page_list() operation is done, but doing this really helps with
maybe you mean
but doing this doesn't really helps
> lock_page() latency.
>
> Does that make sense?
If so, It does make sense.
Thanks for pointing me out.
>
> --
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--
Kind regards,
Minchan Kim
--
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next prev parent reply other threads:[~2013-06-04 6:59 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-03 20:02 [v5][PATCH 0/6] mm: vmscan: Batch page reclamation under shink_page_list Dave Hansen
2013-06-03 20:02 ` [v5][PATCH 1/6] mm: swap: defer clearing of page_private() for swap cache pages Dave Hansen
2013-07-14 23:47 ` Wanpeng Li
2013-07-14 23:47 ` Wanpeng Li
2013-06-03 20:02 ` [v5][PATCH 2/6] mm: swap: make 'struct page' and swp_entry_t variants of swapcache_free() Dave Hansen
2013-07-14 23:48 ` Wanpeng Li
2013-07-14 23:48 ` Wanpeng Li
2013-06-03 20:02 ` [v5][PATCH 3/6] mm: vmscan: break up __remove_mapping() Dave Hansen
2013-07-14 23:49 ` Wanpeng Li
2013-07-14 23:49 ` Wanpeng Li
2013-06-03 20:02 ` [v5][PATCH 4/6] mm: vmscan: break out mapping "freepage" code Dave Hansen
2013-07-14 23:49 ` Wanpeng Li
2013-07-14 23:49 ` Wanpeng Li
2013-06-03 20:02 ` [v5][PATCH 5/6] mm: vmscan: batch shrink_page_list() locking operations Dave Hansen
2013-06-04 1:17 ` Hillf Danton
2013-06-04 5:07 ` Minchan Kim
2013-06-04 15:22 ` Dave Hansen
2013-06-05 7:28 ` Hillf Danton
2013-06-05 7:57 ` Minchan Kim
2013-06-05 14:24 ` Dave Hansen
2013-06-04 5:01 ` Minchan Kim
2013-06-04 6:02 ` Minchan Kim
2013-06-04 15:29 ` Dave Hansen
2013-06-04 23:32 ` Minchan Kim
2013-06-04 6:10 ` Dave Hansen
2013-06-04 6:59 ` Minchan Kim [this message]
2013-07-14 23:50 ` Wanpeng Li
2013-07-14 23:50 ` Wanpeng Li
2013-06-03 20:02 ` [v5][PATCH 6/6] mm: vmscan: drain batch list during long operations Dave Hansen
2013-06-04 6:05 ` Minchan Kim
2013-06-04 15:24 ` Dave Hansen
2013-06-04 23:23 ` Minchan Kim
2013-06-04 23:31 ` Dave Hansen
2013-06-04 23:36 ` Minchan Kim
2013-06-04 23:37 ` Minchan Kim
2013-07-14 23:51 ` Wanpeng Li
2013-07-14 23:51 ` Wanpeng Li
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