memory coordinator: Add MemoryCoordinatorClient::OnPurgeMemory()

memory coordinator: Add MemoryCoordinatorClient::OnPurgeMemory()

Before this CL, MemoryCoordinatorClient has only one callback called
OnMemoryStateChange(). Clients try to free up memory when state change
happens (e.g. NORMAL -> SUSPENDED). This may not be a good strategy on
some platforms because we may touch compressed pages (see [1] for details).

This CL separates logic for purging existing memory from memory state changes.
This way we can build flexible strategies for handling memory pressure.

[1] https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source=footer#!msg/project-trim/s96xSirL2Hs/18uq1zfHEgAJ

BUG=684287
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel

[bashi, 2017-01-24 07:16:59]

Description was changed from

==========
memory coordinator: Add MemoryCoordinatorClient::OnPurgeMemory()

Before this CL, MemoryCoordinatorClient has only one callback called
OnMemoryStateChange(). Clients try to free up memory when state change
happens (e.g. NORMAL -> SUSPENDED). This may not be a good strategy on
some platforms because we may touch compressed pages (see [1] for details).

This CL separates logic for purging existing memory from memory state changes.
This way we can build flexible strategies for handling memory pressure.

[1]
https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source=f...

BUG=684287
==========

to

==========
memory coordinator: Add MemoryCoordinatorClient::OnPurgeMemory()

Before this CL, MemoryCoordinatorClient has only one callback called
OnMemoryStateChange(). Clients try to free up memory when state change
happens (e.g. NORMAL -> SUSPENDED). This may not be a good strategy on
some platforms because we may touch compressed pages (see [1] for details).

This CL separates logic for purging existing memory from memory state changes.
This way we can build flexible strategies for handling memory pressure.

[1]
https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source=f...

BUG=684287
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

[bashi, 2017-01-24 07:26:40]

bashi@chromium.org changed reviewers:
+ hajimehoshi@chromium.org, tasak@google.com

[bashi, 2017-01-24 07:26:40]

tasak@, hajimehoshi@: PTAL? I'll ask OWNERS review if this looks good to you.

tasak@: could you check this doesn't break purge+throttled experiment?

hajimehoshi@: could you check OnMemoryStateChange() changes? The basic rule is
OnMemoryStateChange(THROTTLED) -> OnPurgeMemory()

[bashi, 2017-01-24 07:45:56]

The CQ bit was checked by bashi@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-01-24 07:46:12]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[tasak, 2017-01-24 08:19:12]

On 2017/01/24 07:26:40, bashi wrote:

> tasak@: could you check this doesn't break purge+throttled experiment?

lgtm for purge+throttled experiment.

[commit-bot: I haz the power, 2017-01-24 08:35:48]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-01-24 08:35:48]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[hajimehoshi, 2017-01-24 11:46:31]

lgtm

https://codereview.chromium.org/2648323005/diff/1/base/memory/memory_coordina...
File base/memory/memory_coordinator_client.h (right):

https://codereview.chromium.org/2648323005/diff/1/base/memory/memory_coordina...
base/memory/memory_coordinator_client.h:38: // optimization but that is not
necessary for the process to run (e.g.
'caches' should be in this line.

https://codereview.chromium.org/2648323005/diff/1/base/memory/memory_coordina...
base/memory/memory_coordinator_client.h:66: // any memory whose contents can be
reproduced when transitioning out of
'the' should be in this line

[bashi, 2017-01-26 01:05:49]

Thank you for reviews! I'll separate this CL into small ones.

https://codereview.chromium.org/2648323005/diff/1/base/memory/memory_coordina...
File base/memory/memory_coordinator_client.h (right):

https://codereview.chromium.org/2648323005/diff/1/base/memory/memory_coordina...
base/memory/memory_coordinator_client.h:38: // optimization but that is not
necessary for the process to run (e.g.
On 2017/01/24 11:46:31, hajimehoshi wrote:
> 'caches' should be in this line.

Do you mean s/an optimization/optimization caches/ ?

https://codereview.chromium.org/2648323005/diff/1/base/memory/memory_coordina...
base/memory/memory_coordinator_client.h:66: // any memory whose contents can be
reproduced when transitioning out of
On 2017/01/24 11:46:31, hajimehoshi wrote:
> 'the' should be in this line

Could you elaborate a bit more? Where should I add 'the'?

[bashi, 2017-03-06 23:56:41]

Description was changed from

==========
memory coordinator: Add MemoryCoordinatorClient::OnPurgeMemory()

Before this CL, MemoryCoordinatorClient has only one callback called
OnMemoryStateChange(). Clients try to free up memory when state change
happens (e.g. NORMAL -> SUSPENDED). This may not be a good strategy on
some platforms because we may touch compressed pages (see [1] for details).

This CL separates logic for purging existing memory from memory state changes.
This way we can build flexible strategies for handling memory pressure.

[1]
https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source=f...

BUG=684287
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========

to

==========
memory coordinator: Add MemoryCoordinatorClient::OnPurgeMemory()

Before this CL, MemoryCoordinatorClient has only one callback called
OnMemoryStateChange(). Clients try to free up memory when state change
happens (e.g. NORMAL -> SUSPENDED). This may not be a good strategy on
some platforms because we may touch compressed pages (see [1] for details).

This CL separates logic for purging existing memory from memory state changes.
This way we can build flexible strategies for handling memory pressure.

[1]
https://groups.google.com/a/chromium.org/forum/?utm_medium=email&utm_source=f...

BUG=684287
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
==========