content: Release all free discardable memory when idle.

content: Release all free discardable memory when idle.

This adds better tracking of free discardable memory in child
processes and the ability to release the memory without having
the browser process purge the memory.

BUG=460995
TEST=content_unittests --gtest_filter=DiscardableSharedMemoryHeapTest.*

Committed: https://crrev.com/2ce0228408e0e97653af9ac08b297ce016784d88
Cr-Commit-Position: refs/heads/master@{#319779}

[reveman, 2015-03-07 22:43:57]

reveman@chromium.org changed reviewers:
+ avi@chromium.org

[Avi (use Gerrit), 2015-03-09 16:03:37]

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
File content/common/discardable_shared_memory_heap.cc (right):

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
content/common/discardable_shared_memory_heap.cc:61: DCHECK_EQ(num_free_blocks_,
0u);
Expected value as the first parameter.

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
File content/common/discardable_shared_memory_heap.h (right):

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
content/common/discardable_shared_memory_heap.h:52: // |shared_memory| must be
aligned to the block size and size must be a
What size?

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
content/common/discardable_shared_memory_heap.h:112:
std::vector<linked_ptr<ScopedMemorySegment>> memory_segments_;
Why are you switching to linked_ptr? ScopedVector is preferred.

https://groups.google.com/a/chromium.org/d/msg/chromium-dev/cDHsauJfP5c/U2fHW...

[Avi (use Gerrit), 2015-03-09 17:21:25]

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
File content/common/discardable_shared_memory_heap.h (right):

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
content/common/discardable_shared_memory_heap.h:112:
std::vector<linked_ptr<ScopedMemorySegment>> memory_segments_;
On 2015/03/09 16:03:37, Avi wrote:
> Why are you switching to linked_ptr? ScopedVector is preferred.
> 
>
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/cDHsauJfP5c/U2fHW...

http://crbug.com/137767

[reveman, 2015-03-09 18:08:26]

PTAL

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
File content/common/discardable_shared_memory_heap.h (right):

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
content/common/discardable_shared_memory_heap.h:52: // |shared_memory| must be
aligned to the block size and size must be a
On 2015/03/09 at 16:03:37, Avi wrote:
> What size?

DiscardableSharedMemory::mapped_size(), but I reintroduced the |size| argument
in the latest patch as I think using mapped_size was a bad idea. It should be
possible for mapped_size() to be larger than the size used by heap.

https://codereview.chromium.org/981403002/diff/60001/content/common/discardab...
content/common/discardable_shared_memory_heap.h:112:
std::vector<linked_ptr<ScopedMemorySegment>> memory_segments_;
On 2015/03/09 at 17:21:25, Avi wrote:
> On 2015/03/09 16:03:37, Avi wrote:
> > Why are you switching to linked_ptr? ScopedVector is preferred.
> > 
> >
https://groups.google.com/a/chromium.org/d/msg/chromium-dev/cDHsauJfP5c/U2fHW...
> 
> http://crbug.com/137767

I used linked_ptr as it's not spec compliant to use std::remove_if with
ScopedVector. Changed back to ScopedVector and used std::partition instead of
remove_if in latest patch.

[Avi (use Gerrit), 2015-03-09 18:48:54]

LGTM

[reveman, 2015-03-09 18:59:17]

reveman@chromium.org changed reviewers:
+ rsesek@chromium.org

[reveman, 2015-03-09 18:59:18]

+rsesek for chrome/common/crash_keys.cc

[Robert Sesek, 2015-03-09 19:00:16]

LGTM

[reveman, 2015-03-09 19:03:21]

The CQ bit was checked by reveman@chromium.org

[commit-bot: I haz the power, 2015-03-09 19:04:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/981403002/100001

[reveman, 2015-03-09 21:08:07]

The CQ bit was checked by reveman@chromium.org

[reveman, 2015-03-09 21:08:07]

The patchset sent to the CQ was uploaded after l-g-t-m from rsesek@chromium.org,
avi@chromium.org
Link to the patchset: https://codereview.chromium.org/981403002/#ps120001
(title: "disable DCHECK")

[commit-bot: I haz the power, 2015-03-09 21:08:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/981403002/120001

[commit-bot: I haz the power, 2015-03-09 23:57:34]

Committed patchset #7 (id:120001)

[commit-bot: I haz the power, 2015-03-09 23:58:06]

Patchset 7 (id:??) landed as
https://crrev.com/2ce0228408e0e97653af9ac08b297ce016784d88
Cr-Commit-Position: refs/heads/master@{#319779}