From: Sam Ben <sam.bennn@gmail.com>
To: Robin Holt <holt@sgi.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@kernel.org>,
Nate Zimmer <nzimmer@sgi.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>, Rob Landley <rob@landley.net>,
Mike Travis <travis@sgi.com>,
Daniel J Blueman <daniel@numascale-asia.com>,
Andrew Morton <akpm@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Yinghai Lu <yinghai@kernel.org>, Mel Gorman <mgorman@suse.de>
Subject: Re: [RFC 0/4] Transparent on-demand struct page initialization embedded in the buddy allocator
Date: Wed, 17 Jul 2013 13:17:44 +0800 [thread overview]
Message-ID: <51E628F8.6030303@gmail.com> (raw)
In-Reply-To: <1373594635-131067-1-git-send-email-holt@sgi.com>
On 07/12/2013 10:03 AM, Robin Holt wrote:
> We have been working on this since we returned from shutdown and have
> something to discuss now. We restricted ourselves to 2MiB initialization
> to keep the patch set a little smaller and more clear.
>
> First, I think I want to propose getting rid of the page flag. If I knew
> of a concrete way to determine that the page has not been initialized,
> this patch series would look different. If there is no definitive
> way to determine that the struct page has been initialized aside from
> checking the entire page struct is zero, then I think I would suggest
> we change the page flag to indicate the page has been initialized.
>
> The heart of the problem as I see it comes from expand(). We nearly
> always see a first reference to a struct page which is in the middle
> of the 2MiB region. Due to that access, the unlikely() check that was
> originally proposed really ends up referencing a different page entirely.
> We actually did not introduce an unlikely and refactor the patches to
> make that unlikely inside a static inline function. Also, given the
> strong warning at the head of expand(), we did not feel experienced
> enough to refactor it to make things always reference the 2MiB page
> first.
>
> With this patch, we did boot a 16TiB machine. Without the patches,
> the v3.10 kernel with the same configuration took 407 seconds for
> free_all_bootmem. With the patches and operating on 2MiB pages instead
> of 1GiB, it took 26 seconds so performance was improved. I have no feel
> for how the 1GiB chunk size will perform.
How to test how much time spend on free_all_bootmem?
>
> I am on vacation for the next three days so I am sorry in advance for
> my infrequent or non-existant responses.
>
>
> Signed-off-by: Robin Holt <holt@sgi.com>
> Signed-off-by: Nate Zimmer <nzimmer@sgi.com>
> To: "H. Peter Anvin" <hpa@zytor.com>
> To: Ingo Molnar <mingo@kernel.org>
> Cc: Linux Kernel <linux-kernel@vger.kernel.org>
> Cc: Linux MM <linux-mm@kvack.org>
> Cc: Rob Landley <rob@landley.net>
> Cc: Mike Travis <travis@sgi.com>
> Cc: Daniel J Blueman <daniel@numascale-asia.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Greg KH <gregkh@linuxfoundation.org>
> Cc: Yinghai Lu <yinghai@kernel.org>
> Cc: Mel Gorman <mgorman@suse.de>
> --
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next prev parent reply other threads:[~2013-07-17 5:18 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-12 2:03 [RFC 0/4] Transparent on-demand struct page initialization embedded in the buddy allocator Robin Holt
2013-07-12 2:03 ` [RFC 1/4] memblock: Introduce a for_each_reserved_mem_region iterator Robin Holt
2013-07-12 2:03 ` [RFC 2/4] Have __free_pages_memory() free in larger chunks Robin Holt
2013-07-12 7:45 ` Robin Holt
2013-07-13 3:08 ` Yinghai Lu
2013-07-16 13:02 ` Sam Ben
2013-07-23 15:32 ` Johannes Weiner
2013-07-12 2:03 ` [RFC 3/4] Seperate page initialization into a separate function Robin Holt
2013-07-13 3:06 ` Yinghai Lu
2013-07-15 3:19 ` Robin Holt
2013-07-12 2:03 ` [RFC 4/4] Sparse initialization of struct page array Robin Holt
2013-07-13 4:19 ` Yinghai Lu
2013-07-13 4:39 ` H. Peter Anvin
2013-07-13 5:31 ` Yinghai Lu
2013-07-13 5:38 ` H. Peter Anvin
2013-07-15 14:08 ` Nathan Zimmer
2013-07-15 17:45 ` Nathan Zimmer
2013-07-15 17:54 ` H. Peter Anvin
2013-07-15 18:26 ` Robin Holt
2013-07-15 18:29 ` H. Peter Anvin
2013-07-23 8:32 ` Ingo Molnar
2013-07-23 11:09 ` Robin Holt
2013-07-23 11:15 ` Robin Holt
2013-07-23 11:41 ` Robin Holt
2013-07-23 11:50 ` Robin Holt
2013-07-16 10:26 ` Robin Holt
2013-07-25 2:25 ` Robin Holt
2013-07-25 12:50 ` Yinghai Lu
2013-07-25 13:42 ` Robin Holt
2013-07-25 13:52 ` Yinghai Lu
2013-07-15 21:30 ` Andrew Morton
2013-07-16 10:38 ` Robin Holt
2013-07-12 8:27 ` [RFC 0/4] Transparent on-demand struct page initialization embedded in the buddy allocator Ingo Molnar
2013-07-12 8:47 ` boot tracing Borislav Petkov
2013-07-12 8:53 ` Ingo Molnar
2013-07-15 1:38 ` Sam Ben
2013-07-23 8:18 ` Ingo Molnar
2013-07-12 9:19 ` [RFC 0/4] Transparent on-demand struct page initialization embedded in the buddy allocator Robert Richter
2013-07-15 15:16 ` Robin Holt
2013-07-16 8:55 ` Joonsoo Kim
2013-07-16 9:08 ` Borislav Petkov
2013-07-23 8:20 ` Ingo Molnar
2013-07-15 15:00 ` Robin Holt
2013-07-17 5:17 ` Sam Ben [this message]
2013-07-17 9:30 ` Robin Holt
2013-07-19 23:51 ` Yinghai Lu
2013-07-22 6:13 ` Robin Holt
2013-08-02 17:44 ` [RFC v2 0/5] " Nathan Zimmer
2013-08-02 17:44 ` [RFC v2 1/5] memblock: Introduce a for_each_reserved_mem_region iterator Nathan Zimmer
2013-08-02 17:44 ` [RFC v2 2/5] Have __free_pages_memory() free in larger chunks Nathan Zimmer
2013-08-02 17:44 ` [RFC v2 3/5] Move page initialization into a separate function Nathan Zimmer
2013-08-02 17:44 ` [RFC v2 4/5] Only set page reserved in the memblock region Nathan Zimmer
2013-08-03 20:04 ` Nathan Zimmer
2013-08-02 17:44 ` [RFC v2 5/5] Sparse initialization of struct page array Nathan Zimmer
2013-08-05 9:58 ` [RFC v2 0/5] Transparent on-demand struct page initialization embedded in the buddy allocator Ingo Molnar
2013-08-12 21:54 ` [RFC v3 " Nathan Zimmer
2013-08-12 21:54 ` [RFC v3 1/5] memblock: Introduce a for_each_reserved_mem_region iterator Nathan Zimmer
2013-08-12 21:54 ` [RFC v3 2/5] Have __free_pages_memory() free in larger chunks Nathan Zimmer
2013-08-12 21:54 ` [RFC v3 3/5] Move page initialization into a separate function Nathan Zimmer
2013-08-12 21:54 ` [RFC v3 4/5] Only set page reserved in the memblock region Nathan Zimmer
2013-08-12 21:54 ` [RFC v3 5/5] Sparse initialization of struct page array Nathan Zimmer
2013-08-13 10:58 ` [RFC v3 0/5] Transparent on-demand struct page initialization embedded in the buddy allocator Ingo Molnar
2013-08-13 17:09 ` Linus Torvalds
2013-08-13 17:23 ` H. Peter Anvin
2013-08-13 17:33 ` Mike Travis
2013-08-13 17:51 ` Linus Torvalds
2013-08-13 18:04 ` Mike Travis
2013-08-13 19:06 ` Mike Travis
2013-08-13 20:24 ` Yinghai Lu
2013-08-13 20:37 ` Mike Travis
2013-08-13 21:35 ` Nathan Zimmer
2013-08-13 23:10 ` Nathan Zimmer
2013-08-13 23:55 ` Linus Torvalds
2013-08-14 11:27 ` Ingo Molnar
2013-08-14 11:05 ` Ingo Molnar
2013-08-14 22:15 ` Nathan Zimmer
2013-08-16 16:36 ` Dave Hansen
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