> Currently, it is only possible to read the number of open file descriptors of > a Java process via the `UnixOperatingSystemMXBean` which is only accessible > via JMX enabled tools. To improve servicability, it would be benifical to be > able to view this information from jcmd VM.info output or hs_err_pid crash > logs. This could help diagnose resource exhaustion and troubleshoot "too many > open files" errors in Java processes on Unix platforms. > > This PR adds reporting the current open file descriptor count to both jcmd > VM.info output or hs_err_pid crash logs by refactoring the native JNI logic > from > `Java_com_sun_management_internal_OperatingSystemImpl_getOpenFileDescriptorCount0` > of the `UnixOperatingSystemMXBean` into hotspot. Apple's API for retrieving > open file descriptor count provides an array of the actual FDs to determine > the count. To avoid using `malloc` to store this array in a potential signal > handling context where stack space may be limited, the apple implementation > instead allocates a fixed 32KB struct on the stack to store the open FDs and > only reports the result if the struct is less than the max (1024 FDs). This > should cover the majoirty of use cases.
Kieran Farrell has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 23 commits: - Merge branch 'openjdk:master' into JDK_8359706 - comment - timed loop for aix and linux proc read - rm unused variables - updates - clean up - clean up - undo commit to linux.cpp - rm max count and malloc - bsd.cpp - ... and 13 more: https://git.openjdk.org/jdk/compare/1342db0b...1f34d255 ------------- Changes: https://git.openjdk.org/jdk/pull/27971/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27971&range=05 Stats: 134 lines in 6 files changed: 134 ins; 0 del; 0 mod Patch: https://git.openjdk.org/jdk/pull/27971.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/27971/head:pull/27971 PR: https://git.openjdk.org/jdk/pull/27971
