JDK-8301749 : Tracking malloc pooled memory size
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: runtime
  • Affected Version: 21
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2023-02-03
  • Updated: 2024-07-15
  • Resolved: 2023-02-20
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JDK 21
21 b11Fixed
Related Reports
CSR :  
JDK-8302128 - Tracking malloc pooled memory size
Relates :  
JDK-8302001 - Add jcmd command to print malloc_stats() info
Relates :  
JDK-8249666 - Improve Native Memory Tracking to report the actual RSS usage
Description
Memory not allocated via NMT and uncommitted memory contributes to a discrepancy between NMT and RSS.
It can be hard to distinguish between these cases.
If the VM can determine the amount of pooled memory by malloc it would help with both determining if a trim_native_memory is needed, or there are some allocations happening outside of NMT.

It would be good if the VM can summarize the malloc pooled memory by using e.g. malloc_info(3).

We can thus more precise account for RSS value.
Comments
Changeset: b5a74269 Author: Johan Sjölen <jsjolen@openjdk.org> Date: 2023-02-20 14:23:54 +0000 URL: https://git.openjdk.org/jdk/commit/b5a7426996bb0e36319186756c46cfa7d0ab6e64
20-02-2023
A pull request was submitted for review. URL: https://git.openjdk.org/jdk/pull/12455 Date: 2023-02-07 15:00:14 +0000
07-02-2023