From: Seth Jennings <spartacus06@gmail.com>
To: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Bob Liu <bob.liu@oracle.com>, Mel Gorman <mgorman@suse.de>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Tomasz Stanislawski <t.stanislaws@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Dave Hansen <dave.hansen@intel.com>,
Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH v3 5/6] zswap: replace tree in zswap with radix tree in zbud
Date: Wed, 9 Oct 2013 12:16:17 -0500 [thread overview]
Message-ID: <20131009171617.GA21057@variantweb.net> (raw)
In-Reply-To: <20131009153022.GB5406@variantweb.net>
On Wed, Oct 09, 2013 at 10:30:22AM -0500, Seth Jennings wrote:
> In my approach, I was also looking at allowing the zbud pools to use
> HIGHMEM pages, since the handle is no longer an address. This requires
> the pages that are being mapped to be kmapped (atomic) which will
> disable preemption. This isn't an additional overhead since the
> map/unmap corresponds with a compress/decompress operation at the zswap
> level which uses per-cpu variables that disable preemption already.
On second though, lets not mess with the HIGHMEM page support for now.
Turns out it is tricker than I thought since the unbuddied lists are
linked through the zbud header stored in the page. But we can still
disable preemption to allow per-cpu tracking of the current mapping and
avoid a lookup (and races) in zbud_unmap().
Seth
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WARNING: multiple messages have this Message-ID (diff)
From: Seth Jennings <spartacus06@gmail.com>
To: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Bob Liu <bob.liu@oracle.com>, Mel Gorman <mgorman@suse.de>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Tomasz Stanislawski <t.stanislaws@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Dave Hansen <dave.hansen@intel.com>,
Minchan Kim <minchan@kernel.org>
Subject: Re: [PATCH v3 5/6] zswap: replace tree in zswap with radix tree in zbud
Date: Wed, 9 Oct 2013 12:16:17 -0500 [thread overview]
Message-ID: <20131009171617.GA21057@variantweb.net> (raw)
In-Reply-To: <20131009153022.GB5406@variantweb.net>
On Wed, Oct 09, 2013 at 10:30:22AM -0500, Seth Jennings wrote:
> In my approach, I was also looking at allowing the zbud pools to use
> HIGHMEM pages, since the handle is no longer an address. This requires
> the pages that are being mapped to be kmapped (atomic) which will
> disable preemption. This isn't an additional overhead since the
> map/unmap corresponds with a compress/decompress operation at the zswap
> level which uses per-cpu variables that disable preemption already.
On second though, lets not mess with the HIGHMEM page support for now.
Turns out it is tricker than I thought since the unbuddied lists are
linked through the zbud header stored in the page. But we can still
disable preemption to allow per-cpu tracking of the current mapping and
avoid a lookup (and races) in zbud_unmap().
Seth
next prev parent reply other threads:[~2013-10-09 17:16 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-08 13:29 [PATCH v3 0/6] mm: migrate zbud pages Krzysztof Kozlowski
2013-10-08 13:29 ` Krzysztof Kozlowski
2013-10-08 13:29 ` [PATCH v3 1/6] zbud: use page ref counter for " Krzysztof Kozlowski
2013-10-08 13:29 ` Krzysztof Kozlowski
2013-10-08 20:43 ` Seth Jennings
2013-10-09 7:08 ` Krzysztof Kozlowski
2013-10-09 7:08 ` Krzysztof Kozlowski
2013-10-08 13:29 ` [PATCH v3 2/6] zbud: make freechunks a block local variable Krzysztof Kozlowski
2013-10-08 13:29 ` Krzysztof Kozlowski
2013-10-08 20:46 ` Seth Jennings
2013-10-08 13:29 ` [PATCH v3 3/6] mm: use mapcount for identifying zbud pages Krzysztof Kozlowski
2013-10-08 13:29 ` Krzysztof Kozlowski
2013-10-08 13:29 ` [PATCH v3 4/6] zbud: memset zbud_header to 0 during init Krzysztof Kozlowski
2013-10-08 13:29 ` Krzysztof Kozlowski
2013-10-08 20:48 ` Seth Jennings
2013-10-08 13:29 ` [PATCH v3 5/6] zswap: replace tree in zswap with radix tree in zbud Krzysztof Kozlowski
2013-10-08 13:29 ` Krzysztof Kozlowski
2013-10-09 15:30 ` Seth Jennings
2013-10-09 15:30 ` Seth Jennings
2013-10-09 17:16 ` Seth Jennings [this message]
2013-10-09 17:16 ` Seth Jennings
2013-10-10 7:01 ` Krzysztof Kozlowski
2013-10-10 7:01 ` Krzysztof Kozlowski
2013-10-08 13:29 ` [PATCH v3 6/6] mm: migrate zbud pages Krzysztof Kozlowski
2013-10-08 13:29 ` Krzysztof Kozlowski
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