RFR (S): 8214816: os::read() should not transition to _thread_blocked with safepoint check on Solaris

[Jiangli Zhou]

Hi David,

The history lesson on os::read is fascinating! The cleanup looks nice to 
me.

src/hotspot/os/windows/os_windows.cpp copyright year also needs update.

Thanks,

Jiangli


On 1/9/19 5:00 PM, David Holmes wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8214816
> webrev: http://cr.openjdk.java.net/~dholmes/8214816/webrev/
>
> Please see the bug report for detailed background. In short summary 
> all platforms now have the same os::read and os::read_at that doesn't 
> do safepoint checks. Most of the changes are code deletions:
>
> - removed unused os::restartable_read() method
> - removed os::read from all os_*.cpp files and added shared inline 
> definition in os.inline.hpp (checked all callsites already have 
> os.inline.hpp included)
> - removed os::read_at from all non-Windows os_*.cpp files and added 
> shared definition in os_posix.cpp (simple wrapper to pread())
> - fixed the return type of os::read and os::read_at to be ssize_t not 
> size_t.
>
> Also fixed os::read error handling in 
> src/hotspot/share/compiler/directivesParser.cpp, and filed JDK-8216461 
> to have a JFR usage of os::read_at fixed.
>
> Also changed src/hotspot/share/runtime/arguments.cpp to use os::read 
> as it no longer needs to avoid the thread-state-transition. Arguably 
> we could go the other way here and remove os::read completely and use 
> the native ::read on all platforms - there are already uses of ::read 
> elsewhere in the code.
>
> Testing: Mach5 tiers 1 - 3
>
> Thanks,
> David