> The proposal is to encapsulate the nmethod mark for deoptimization logic in
> one place and only allow access to the `mark_for_deoptimization` from a
> closure object:
> ```C++
> class DeoptimizationMarkerClosure : StackObj {
> public:
> virtual void marker_do(Deoptimization::MarkFn mark_fn) = 0;
> };
>
> This closure takes a `MarkFn` which it uses to mark which nmethods should be
> deoptimized. This marking can only be done through the `MarkFn` and a
> `MarkFn` can only be created in the following code which runs the closure.
> ```C++
> {
> NoSafepointVerifier nsv;
> assert_locked_or_safepoint(Compile_lock);
> marker_closure.marker_do(MarkFn());
> anything_deoptimized = deoptimize_all_marked();
> }
> if (anything_deoptimized) {
> run_deoptimize_closure();
> }
>
> This ensures that this logic is encapsulated and the `NoSafepointVerifier`
> and `assert_locked_or_safepoint(Compile_lock)` makes `deoptimize_all_marked`
> not having to scan the whole code cache sound.
>
> The exception to this pattern, from `InstanceKlass::unload_class`, is
> discussed in the JBS issue, and gives reasons why not marking for
> deoptimization there is ok.
>
> An effect of this encapsulation is that the deoptimization logic was moved
> from the `CodeCache` class to the `Deoptimization` class and the class
> redefinition logic was moved from the `CodeCache` class to the
> `VM_RedefineClasses` class/operation.
>
> Testing: Tier 1-5
Axel Boldt-Christmas has updated the pull request incrementally with three
additional commits since the last revision:
- Add assertions
- Fix marked logic
- Erik refactorings
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/9655/files
- new: https://git.openjdk.org/jdk/pull/9655/files/f77f44eb..5d26ab8d
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=9655&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=9655&range=00-01
Stats: 339 lines in 14 files changed: 85 ins; 144 del; 110 mod
Patch: https://git.openjdk.org/jdk/pull/9655.diff
Fetch: git fetch https://git.openjdk.org/jdk pull/9655/head:pull/9655
PR: https://git.openjdk.org/jdk/pull/9655
