RFR (XS): CR 8004330: Add missing Unsafe entry points for addAndGet() family (original) (raw)
Aleksey Shipilev aleksey.shipilev at oracle.com
Wed Jan 9 13:04:32 UTC 2013
- Previous message: RFR (XS): CR 8004330: Add missing Unsafe entry points for addAndGet() family
- Next message: RFR (XS): CR 8004330: Add missing Unsafe entry points for addAndGet() family
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
On 01/09/2013 05:02 PM, Doug Lea wrote:
The main point to keep in mind is that the fallback wrapper (unsafe.cpp UnsafeCompareAndSwapLong) does what you expect (uses the enclosing lock), unless you are in an uncommon (and possibly non-existent) situation where you need/expect something else.
Ok, so the bottom-line seems to be: a) Unsafe provides the essential semantics for long updates, even in the absence of long CASes on target hardware. b) New Unsafe code from this CR relies on Unsafe methods semantics from (a), thus making David's worries ungrounded. c) While existing, Java-level AtomicLong.VM_SUPPORT_LONG_CAS is redundant, and can be eliminated. AtomicLongFieldUpdater can be rewritten to use Unsafe on all the paths.
-Aleksey.
- Previous message: RFR (XS): CR 8004330: Add missing Unsafe entry points for addAndGet() family
- Next message: RFR (XS): CR 8004330: Add missing Unsafe entry points for addAndGet() family
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]