If a large object is truncated, also truncate the page.

If a large object is truncated, also truncate the page.

If GC sweeper finds a truncated large object, the page is shrunk to fit.

Allows reclaiming memory when a large string is externalized.

R=iposva@google.com

Committed: https://code.google.com/p/dart/source/detail?r=37842

[Ivan Posva, 2014-06-30 05:51:05]

LGTM once we use size in words.

Thanks,
-Ivan

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.cc
File runtime/vm/gc_sweeper.cc (right):

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.cc...
runtime/vm/gc_sweeper.cc:64: bytes_to_end += raw_obj->Size();
+= -> =

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.h
File runtime/vm/gc_sweeper.h (right):

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.h#...
runtime/vm/gc_sweeper.h:29: // Returns the number of bytes from
page->object_start() to the end of the
Please change this to "number of words" and update the corresponding code.

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/pages.cc#newc...
runtime/vm/pages.cc:561: if (bytes_to_end < (page->object_end() -
page->object_start())) {
I am wondering whether we want to move the logic here into TruncateLargePage by
checking whether the the old page size and new page size differ.

[koda, 2014-06-30 22:57:49]

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.cc
File runtime/vm/gc_sweeper.cc (right):

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.cc...
runtime/vm/gc_sweeper.cc:64: bytes_to_end += raw_obj->Size();
On 2014/06/30 05:51:05, Ivan Posva wrote:
> += -> =

Done.

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.h
File runtime/vm/gc_sweeper.h (right):

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/gc_sweeper.h#...
runtime/vm/gc_sweeper.h:29: // Returns the number of bytes from
page->object_start() to the end of the
On 2014/06/30 05:51:05, Ivan Posva wrote:
> Please change this to "number of words" and update the corresponding code.

Done.

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/pages.cc
File runtime/vm/pages.cc (right):

https://codereview.chromium.org/355123002/diff/40001/runtime/vm/pages.cc#newc...
runtime/vm/pages.cc:561: if (bytes_to_end < (page->object_end() -
page->object_start())) {
On 2014/06/30 05:51:05, Ivan Posva wrote:
> I am wondering whether we want to move the logic here into TruncateLargePage
by
> checking whether the the old page size and new page size differ.

Done.

[koda, 2014-06-30 22:59:13]

Committed patchset #3 manually as r37842 (presubmit successful).