drivers: xen: gnttab: process gentabs in reverse order #109
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lorc
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Jun 10, 2024
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(XEN) xen-source/xen/common/grant_table.c:1909:d0v0 Expanding d0 \
grant table from 1 to 2 frames
This message is being printed only if Xen is being build in debug mode. So it is not a problem in production mode.
I don't believe that this patch will get into Zephyr mainline. You can try, though.
But as you are trying to include it into rpi5_dev branch, I have no objections.
Acked-by: Volodymyr Babchuk <[email protected]>
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The Linux Kernel has the following: So, nothing special here really - just a bit faster and less logs. |
This is a better justification than "avoid printing debug logs". I believe, if you'll rewrite the commit message WRT to this, it would be much better. |
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firscity
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Jun 14, 2024
The Xen extends domain grant tables every time domain requests gnttab basing on gnttab idx. If idx > xen_current_max_gnttab_idx the Xen extends grant table so that idx <= xen_current_max_gnttab_idx. The growing grant tables on every hypercall is a bit costly operation and it also results in the bunch of log messages: (XEN) xen-source/xen/common/grant_table.c:1909:d0v0 Expanding d0 \ grant table from 1 to 2 frames This patch changes gnttab processing from gnttab max_idx to low_idx, so the first hypercall has the largest index, ensuring that the grant table will grow only once. It also reduces number of log messages. Signed-off-by: Grygorii Strashko <[email protected]> Acked-by: Volodymyr Babchuk <[email protected]> Reviewed-by: Dmytro Firsov <[email protected]>
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The Xen extends domain gentab region every time domain requests gentab basing on gentab idx. If idx > xen_current_max_gentab_idx the Xen extends number of gentabs so that idx <= xen_current_max_gentab_idx. As result now when gentabs are requested from gentab low_idx to max_idx Xen is performing gentab extension by 1 and the bunch of log messages is produced:
(XEN) xen-source/xen/common/grant_table.c:1909:d0v0 Expanding d0
grant table from 1 to 2 frames
This patch changes gentab processing from gentab max_idx to low_idx which allows Xen to perform gentab extension only once (to max_idx) and only one message will be produced in the log:
(XEN) xen-source/xen/common/grant_table.c:1909:d0v0 Expanding d0
grant table from 1 to 64 frames