8292562: (fc) Use copy_file_range in FileChannel::transferTo on Linux

[bplb]

Add copy_file_range(2) to the native Linux implementation of FileChannel::transferTo.

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Issue

• JDK-8292562: (fc) Use copy_file_range in FileChannel::transferTo on Linux

Reviewers

• Alan Bateman (@AlanBateman - Reviewer)

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[mlbridge]

Webrevs

• 09: Full - Incremental (6182d3b0)
• 08: Full - Incremental (e8c4d4bb)
• 07: Full - Incremental (6351c8d2)
• 06: Full - Incremental (ec2ad5d5)
• 05: Full - Incremental (e10abedd)
• 04: Full - Incremental (34e03520)
• 03: Full - Incremental (c3c36f1d)
• 02: Full - Incremental (88750dc5)
• 01: Full - Incremental (ee29211e)
• 00: Full (7c251bd8)

[AlanBateman]

Aside from the check if copy_file_range is supported then I think the change to the transferTo implementation in c3c36f1 looks good. At some point I would expect we will pass the append flag from the java code. Have you looked at transferFrom for the append case? I suspect it is masked by the check for EBADF and now may be the time to re-examine that (okay to be a separate PR but hopefully you see the issue there).

[openjdk]

@bplb This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8292562: (fc) Use copy_file_range in FileChannel::transferTo on Linux

Reviewed-by: alanb

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 116 new commits pushed to the master branch:

• 3844685: 8292697: ZGC: Hangs when almost out of metaspace memory
• 2b80349: 8292669: IGV: Search not useable when in Overflow Toolbar
• 4732abf: 8292910: Remove root to oop cast in HeapDumper
• f694f8a: 8292083: Detected container memory limit may exceed physical machine memory
• f91943c: 8292868: Explicitly pass a third temp register to MacroAssembler::store_heap_oop for aarch64
• 6354a57: 8290711: assert(false) failed: infinite loop in PhaseIterGVN::optimize
• 3e18773: 8292880: Improve debuggee logging for com/sun/jdi/ClassUnloadEventTest.java
• 909e1ed: 8292919: Build failure due to UseJVMCICompiler was not declared when C2 is disabled after JDK-8292691
• 55f5a83: 8282410: Remove SA ProcDebugger support
• d83faea: 8292250: Create test for co-located JDI MethodEntry, Step, and Breakpoint events
• ... and 106 more: https://git.openjdk.org/jdk/compare/494d3873b1d0f7e3ca0a063b44362e7242298dec...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[bplb]

At some point I would expect we will pass the append flag from the java code.

Agreed.

Have you looked at transferFrom for the append case? I suspect it is masked by the check for EBADF

Yep, same problem.

and now may be the time to re-examine that (okay to be a separate PR but hopefully you see the issue there).

Might as well go ahead and fix this in another rev of this PR.

[AlanBateman]

I think this one is done.

[bplb]

I think this one is done.

Well, maybe it is now: the new test failed on macOS and Windows which do not have the problem reported in JDK-4950302. Fixed in commit ec2ad5d.

[AlanBateman]

I think this one is done.

Well, maybe it is now: the new test failed on macOS and Windows which do not have the problem reported in ...

A long standing issue is that FileChannel needs to specify how methods that take a position behave when a file is opened for append. This includes the transferXXX methods. It may be that transferFrom needs to be allowed to throw an exception when called on a FileChannel to a file opened for append. So maybe the simplest thing for now is to revert the test back to testing transferTo when the target is opened for append. That will be a simpler test to maintain.

[bplb]

[M]aybe the simplest thing for now is to revert the test back to testing transferTo when the target is opened for append.

So changed in 6351c8d and limited to run on Linux only.

[AlanBateman]

The test no longer needs to build jdk.test.lib.Platform, otherwise the update looks okay.

[bplb]

The test no longer needs to build jdk.test.lib.Platform, otherwise the update looks okay.

Ack. I had to forget something. Fixed in 6182d3b.

[AlanBateman]

The test no longer needs to build jdk.test.lib.Platform, otherwise the update looks okay.

Ack. I had to forget something. Fixed in 6182d3b.

Thanks. MIN_SIZE is a left-over too, we can get that the next time.

[bplb]

/integrate

[openjdk]

Going to push as commit c74b6d4.
Since your change was applied there have been 116 commits pushed to the master branch:

• 3844685: 8292697: ZGC: Hangs when almost out of metaspace memory
• 2b80349: 8292669: IGV: Search not useable when in Overflow Toolbar
• 4732abf: 8292910: Remove root to oop cast in HeapDumper
• f694f8a: 8292083: Detected container memory limit may exceed physical machine memory
• f91943c: 8292868: Explicitly pass a third temp register to MacroAssembler::store_heap_oop for aarch64
• 6354a57: 8290711: assert(false) failed: infinite loop in PhaseIterGVN::optimize
• 3e18773: 8292880: Improve debuggee logging for com/sun/jdi/ClassUnloadEventTest.java
• 909e1ed: 8292919: Build failure due to UseJVMCICompiler was not declared when C2 is disabled after JDK-8292691
• 55f5a83: 8282410: Remove SA ProcDebugger support
• d83faea: 8292250: Create test for co-located JDI MethodEntry, Step, and Breakpoint events
• ... and 106 more: https://git.openjdk.org/jdk/compare/494d3873b1d0f7e3ca0a063b44362e7242298dec...master

Your commit was automatically rebased without conflicts.

[openjdk]

@bplb Pushed as commit c74b6d4.

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