[v8.x] backport some V8 platform changes by addaleax · Pull Request #20901 · nodejs/node

This splits the task queue used for asynchronous tasks scheduled
by V8 in per-isolate queues, so that multiple threads can be supported.

Original-PR-URL: ayojs/ayo#89
Original-Reviewed-By: Timothy Gu <timothygu99@gmail.com>
PR-URL: nodejs#16700
Reviewed-By: James M Snell <jasnell@gmail.com>

Worker threads need an event loop without active libuv handles in
order to shut down. One source of handles that was previously
not accounted for were delayed V8 tasks; these create timers
that would be standing in the way of clearing the event loop.

To solve this, keep track of the scheduled tasks in a list
and close their timer handles before the corresponding isolate/loop
is removed from the platform.

It is not clear from the V8 documentation what the expectation is
with respect to pending background tasks at the end of the
isolate lifetime; however, an alternative approach of executing
these scheduled tasks when flushing them led to an infinite loop
of tasks scheduling each other; so it seems safe to assume that
the behaviour implemented in this patch is at least acceptable.

Original-PR-URL: ayojs/ayo#120
Original-Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
PR-URL: nodejs#16700
Reviewed-By: James M Snell <jasnell@gmail.com>

Replace raw pointers in task queues with std::unique_ptr. This
makes ownership obvious.

PR-URL: nodejs#16970
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Use std::unique_ptr for delayed tasks in the scheduled
delayed tasks vector. This makes it clear that the vector
has ownership of the delayed tasks and is responsible for
deleting them.

Use a custom deleter for the pointers because libuv
needs to close the handle and then delete the data. Provide
the handle when creating the pointer instead of invoking the
special delete action everytime an element is removed from the vector.

PR-URL: nodejs#17083
Reviewed-By: Anna Henningsen <anna@addaleax.net>

This splits the task queue used for asynchronous tasks scheduled
by V8 in per-isolate queues, so that multiple threads can be supported.

Backport-PR-URL: #20901
Original-PR-URL: ayojs/ayo#89
Original-Reviewed-By: Timothy Gu <timothygu99@gmail.com>
PR-URL: #16700
Reviewed-By: James M Snell <jasnell@gmail.com>

Worker threads need an event loop without active libuv handles in
order to shut down. One source of handles that was previously
not accounted for were delayed V8 tasks; these create timers
that would be standing in the way of clearing the event loop.

To solve this, keep track of the scheduled tasks in a list
and close their timer handles before the corresponding isolate/loop
is removed from the platform.

It is not clear from the V8 documentation what the expectation is
with respect to pending background tasks at the end of the
isolate lifetime; however, an alternative approach of executing
these scheduled tasks when flushing them led to an infinite loop
of tasks scheduling each other; so it seems safe to assume that
the behaviour implemented in this patch is at least acceptable.

Backport-PR-URL: #20901
Original-PR-URL: ayojs/ayo#120
Original-Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
PR-URL: #16700
Reviewed-By: James M Snell <jasnell@gmail.com>

Replace raw pointers in task queues with std::unique_ptr. This
makes ownership obvious.

Backport-PR-URL: #20901
PR-URL: #16970
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Use std::unique_ptr for delayed tasks in the scheduled
delayed tasks vector. This makes it clear that the vector
has ownership of the delayed tasks and is responsible for
deleting them.

Use a custom deleter for the pointers because libuv
needs to close the handle and then delete the data. Provide
the handle when creating the pointer instead of invoking the
special delete action everytime an element is removed from the vector.

Backport-PR-URL: #20901
PR-URL: #17083
Reviewed-By: Anna Henningsen <anna@addaleax.net>

This splits the task queue used for asynchronous tasks scheduled
by V8 in per-isolate queues, so that multiple threads can be supported.

Backport-PR-URL: #20901
Original-PR-URL: ayojs/ayo#89
Original-Reviewed-By: Timothy Gu <timothygu99@gmail.com>
PR-URL: #16700
Reviewed-By: James M Snell <jasnell@gmail.com>

Worker threads need an event loop without active libuv handles in
order to shut down. One source of handles that was previously
not accounted for were delayed V8 tasks; these create timers
that would be standing in the way of clearing the event loop.

To solve this, keep track of the scheduled tasks in a list
and close their timer handles before the corresponding isolate/loop
is removed from the platform.

It is not clear from the V8 documentation what the expectation is
with respect to pending background tasks at the end of the
isolate lifetime; however, an alternative approach of executing
these scheduled tasks when flushing them led to an infinite loop
of tasks scheduling each other; so it seems safe to assume that
the behaviour implemented in this patch is at least acceptable.

Backport-PR-URL: #20901
Original-PR-URL: ayojs/ayo#120
Original-Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
PR-URL: #16700
Reviewed-By: James M Snell <jasnell@gmail.com>

Replace raw pointers in task queues with std::unique_ptr. This
makes ownership obvious.

Backport-PR-URL: #20901
PR-URL: #16970
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>

Use std::unique_ptr for delayed tasks in the scheduled
delayed tasks vector. This makes it clear that the vector
has ownership of the delayed tasks and is responsible for
deleting them.

Use a custom deleter for the pointers because libuv
needs to close the handle and then delete the data. Provide
the handle when creating the pointer instead of invoking the
special delete action everytime an element is removed from the vector.

Backport-PR-URL: #20901
PR-URL: #17083
Reviewed-By: Anna Henningsen <anna@addaleax.net>