[Bug 257318] uma consumes memory when reattaching device
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Date: Fri, 20 Aug 2021 18:24:14 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=257318 --- Comment #1 from jcaplan@blackberry.com --- Just to add a bit more detail. A single iteration might look like this: # sysctl vm.uma_kmem_total vm.uma_kmem_total: 26247168 #devctl attach pci0:3:0:0 #devctl detach pci0:3:0:0 # sysctl vm.uma_kmem_total vm.uma_kmem_total: 26251264 Comparing the output before and after for vmstat -m shows that there is no change in dynamic memory allocated from malloc(). However we see from vm.uma_kmem_total that the UMA is gradually consuming more memory, and a diff of vmstat -z shows several changes in zone allocations at the UMA layer. It appears that all allocations are accounted for at the malloc level yet there is a continuous slow leak of additional pages allocated at the UMA level. I'm not sure there's anything particularly special about mounting/unmounting, it's just an obviously reversible operation that allocates and then frees a lot of memory. So it's possible this is a specific instance of a more general problem. -- You are receiving this mail because: You are the assignee for the bug.