Messages in this thread | | | Date | Thu, 21 Nov 2013 08:42:53 +0800 | From | Bob Liu <> | Subject | Re: [PATCH v2] mm/zswap: change zswap to writethrough cache |
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Hi Dan,
On 11/21/2013 03:49 AM, Dan Streetman wrote: > Currently, zswap is writeback cache; stored pages are not sent > to swap disk, and when zswap wants to evict old pages it must > first write them back to swap cache/disk manually. This avoids > swap out disk I/O up front, but only moves that disk I/O to > the writeback case (for pages that are evicted), and adds the > overhead of having to uncompress the evicted pages, and adds the > need for an additional free page (to store the uncompressed page) > at a time of likely high memory pressure. Additionally, being > writeback adds complexity to zswap by having to perform the > writeback on page eviction. >
Good work!
> This changes zswap to writethrough cache by enabling > frontswap_writethrough() before registering, so that any > successful page store will also be written to swap disk. All the > writeback code is removed since it is no longer needed, and the > only operation during a page eviction is now to remove the entry > from the tree and free it. >
Could you do some testing using eg. SPECjbb? And compare the result with original zswap.
Thanks, -Bob
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