On MacOS, RSS is much larger than explicit

Status

()

Core
General
6 years ago
5 years ago

People

(Reporter: Justin Lebar (not reading bugmail), Assigned: Justin Lebar (not reading bugmail))

Tracking

(Blocks: 1 bug)

Firefox Tracking Flags

(Not tracked)

Details

(Whiteboard: [MemShrink:P2])

(Assignee)

Description

6 years ago
bz had the following numbers on his 10.6 machine:

1,356,769,377 B ── explicit
  940,710,232 B ── heap-allocated
1,072,316,416 B ── heap-committed
         12.27% ── heap-committed-fragmentation
    3,321,856 B ── heap-dirty
  271,441,040 B ── heap-unallocated
  394,264,576 B ── js-gc-heap
  113,790,976 B ── js-main-runtime-gc-heap-decommitted
1,694,748,672 B ── resident

Notice that RSS is 338mb higher than explicit.

It's expected that RSS will be higher than explicit, but the difference should be mainly code (and explicit gets an unfair increase from non-resident memory, mainly gc-heap-decommitted, that njn made me put in explicit).

Anyway, what I think might be happening is that malloc_double_purge isn't working properly.  It's supposed to decommit MADV_FREE'd pages when you view about:memory, but maybe it's not.

Comment 1

6 years ago
P2 per Memshrink
Whiteboard: [MemShrink] → [MemShrink:P2]
(Assignee)

Comment 2

5 years ago
One way one could look into this is by running the vmmap command.
(Assignee)

Updated

5 years ago
Blocks: 819768
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