1668506 - Use PBackground instead of PContent for syncing SessionStorage to reduce main thread parent process usage

Status: RESOLVED DUPLICATE of bug 1654080

(Core :: Storage: localStorage & sessionStorage, enhancement)

Comment 1

[Tom Tung [:tt, :ttung]]

Attachment: Bug 1668506 - Use PBackground for syncing SessionStorageCache;

This patch does:

• Move IPC from PContent to PBackground (SessionStorageManager{Child, Parent}).
• Change SessionStorageManager and BrowsingContext's relationship.
• Expose a getter function to get a manager for top context id on the parent.
• Make SessionStorageManagerParent maintain (originAttrs, originKeys) table. So
  that we don't need to traverse whole originRecord table in manager while it's
  destoryed.

Follow-up work:

• Maybe write SSCache in to disk if it's not loaded after a certain time rather
  than keeping it as in-memory objects until shuting down.

IPC

• Before this patch:
  • Copy from parent while loading a document.
    • Mark cache entry on the parent process as loaded by the child id.
  • Update change on checkpoint.
  • Unmark cache entry on the parent process as unloaded for the child id while
    the parent actor is destorying.
• After this patch:
  • Sync IPC load in the first SessionStorage operation.
    • Mark cache entry on the parent process as loaded by the parent actor
      pointer.
  • Update change on checkpoint
  • Unmark cache entry on the parent process as loaded by the parent actor
    pointer while parent actor is destorying.

SessionStorageManager's lifecycle on the parent process.

• Before this patch:
  • Lives on the main thread
  • Create a cycle for SessionStorageManager and BrowsingContext pair (bc is
    also held by SessionStorageManager) while a content process shutdowns.
  • IIUC, destory during the parent process shutdowns (CC)
• After this patch:
  • On the parent process, lives on the background thread.
  • Create SessionStorageManager that held by static global mananger list
    sManagers.
  • Destory on the background thread after receiving profile-before-change
    topic.
  • Note that there are SessionStorageManager that live on the main thread.
    However their sessionStorages are not used and thus are not registered on
    the manager list.

Comment 2

[Tom Tung [:tt, :ttung]]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=88f6d5c1de3587831814fa5321e5f2a91c612d87&selectedTaskRun=V2odoQG3RKqoHcFNUOoMpQ.0

Comment 3

[Tom Tung [:tt, :ttung]]

Discussed with Jan and we decided to fold the remaining patches together to make it easier to be review.

Comment 4

[Tom Tung [:tt, :ttung]]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=d9525d322f74bd1323a22365f8da82a72809dc2c

Comment 5

[Tom Tung [:tt, :ttung]]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=ce0aacc7b581af327f6094e05c7d5db4e74df714

Comment 6

[Tom Tung [:tt, :ttung]]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=e3983d1cba0ff05295466469a6ba5e9af77fcace

Comment 7

[Tom Tung [:tt, :ttung]]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=6a464c9f3f4ccd984442e4ab229cb7097faf39f4

Comment 8

[Tom Tung [:tt, :ttung]]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=ee0381db14c08d3cb1a7a6ec165c60333b2637fc

Comment 9

[Tom Tung [:tt, :ttung]]

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=61c6b1c638fad3b1991327413fa0e7e39c94f03e

Comment 10

[Tom Tung [:tt, :ttung]]

The patch has been merged to bug 1654080.