sdm660-common: Disable dm-verity hash prefetching.

Prefetching appears to have a slightly negative effect on boot time, and
actually makes boot time much worse when the available dm-bufio cache
shrinks. Since we anticipate the dm-bufio cache will shrink (because of
an increasing number of APEX dm-verity targets), disable prefetching
completely.

Boot time w/o this change:  12.085
Boot time with this change: 11.958

Boot time w/o this change with 128kB dm-bufio cache: 22.82
Boot time with this change with 128kB dm-bufio cache: 12.007

Test: atest google/perf/boottime/boottime-test
Bug: 136247322
Change-Id: I12e342c5692fa89855d9c217f2e94287ff5642a6
This commit is contained in:
Martijn Coenen 2019-08-28 10:17:28 +02:00 committed by OdSazib
parent 841ea5390b
commit 6580fdc5be
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GPG key ID: 0954440B60470871

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@ -27,6 +27,9 @@
# #
# #
on early-init
write /sys/module/dm_verity/parameters/prefetch_cluster 0
on early-boot on early-boot
# Update dm-verity state and set partition.*.verified properties # Update dm-verity state and set partition.*.verified properties
verity_update_state verity_update_state