74a852479c
Persistent grants feature provides high scalability. On some small systems, however, it could incur data copy overheads[1] and thus it is required to be disabled. It can be disabled from blkback side using a module parameter, 'feature_persistent'. But, it is impossible from blkfront side. For the reason, this commit adds a blkfront module parameter for disabling of the feature. [1] https://wiki.xen.org/wiki/Xen_4.3_Block_Protocol_Scalability Signed-off-by: SeongJae Park <sjpark@amazon.de> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20200923061841.20531-3-sjpark@amazon.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
20 lines
919 B
Plaintext
20 lines
919 B
Plaintext
What: /sys/module/xen_blkfront/parameters/max
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Date: June 2013
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KernelVersion: 3.11
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Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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Description:
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Maximum number of segments that the frontend will negotiate
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with the backend for indirect descriptors. The default value
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is 32 - higher value means more potential throughput but more
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memory usage. The backend picks the minimum of the frontend
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and its default backend value.
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What: /sys/module/xen_blkfront/parameters/feature_persistent
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Date: September 2020
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KernelVersion: 5.10
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Contact: SeongJae Park <sjpark@amazon.de>
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Description:
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Whether to enable the persistent grants feature or not. Note
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that this option only takes effect on newly created frontends.
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The default is Y (enable).
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