Messages in this thread | | | From | Yun Levi <> | Date | Wed, 30 Nov 2022 15:01:29 +0900 | Subject | [Question] Should we reuse target when damon's operation changed? |
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Hello SJ.
While I try to use damon, I have some questions whether it is correct to reuse damon_target structure when damon's operation is changed.
At first, one user set up damon like below. echo 1 > /sys/kernel/mm/damon/admin/kdamonds/nr_kdamonds echo 1 > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/nr_contexts echo 1 > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/nr_targets echo 1 > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/pid_target echo 1 > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/regions/nr_regions echo 0 > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/regions/nr_regions/0/start echo 16384 > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/targets/regions/nr_regions/0/end
echo vaddr > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/operation echo on > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/state
And some time pass, user change the operation as "paddr" like below: echo paddr > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/operation echo commit > /sys/kernel/mm/damon/admin/kdamonds/0/contexts/0/state
In that situation, the damon_target is reused and the region isn't changed, former region information which damon_region has -- nr_accesse, last_nr_accesss, last_sample addr is kept.
But, former accessed information is based on vaddr and changed accessed information should be based on paddr and it seems the wrong information to new applied operation.
IIUC, it makes some confusion to kdamond when it merges or splits regions based on above information.
So, Is it much better to remove the target and region information when the operation is changed? or should we check whether it's possible to reuse former access information between former and new operation?
Thanks.
-- Best regards, Levi
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