review request for 7142641: -Xshared:on fails on ARM
dean.long at oracle.com
Tue Feb 28 14:05:42 PST 2012
Summary of changes: 3 lines changed: 0 ins; 2 del; 1 mod; 5538 unchg
The Class Data Sharing file is mapped "shared" on linux, which places
extra constraints on which virtual address a file offset can use. This
is to ensure consistency on certain platforms with aliasing caches.
However as the CDS file is opened read-only, mapping it "shared" has no
benefit and can cause the mmap to fail. The simplest fix is to change
the mapping to "private".
Tested on linux arm platform with aliasing cache. Installed CDS with
-Xshare:dump then ran through some vm tests as a sanity check.
This bug is on the 7u4 watch list.
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