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Make sure UDP send callbacks are always fired asynchronously - #371

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saghul merged 2 commits into
libuv:v1.xfrom
saghul:udp_async
May 28, 2015
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Make sure UDP send callbacks are always fired asynchronously#371
saghul merged 2 commits into
libuv:v1.xfrom
saghul:udp_async

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@saghul

@saghul saghul commented May 27, 2015

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R=@bnoordhuis

Fixes: #301

@saghul

saghul commented May 27, 2015

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Well, fuck.I'm afraid the change to uv__run_pending has some interesting side effects, as in 40 failing tests or something :-(

@saghul

saghul commented May 27, 2015

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The problem seems to be the following:

  • The first time around, uv_udp_send sends immediately, so uv__udp_sendmsg is called and the io handle is set as pending with uv__io_feed, in order to run the callback on the next tick.
  • On the next tick, while in uv__run_pending, we call uv_udp_send again, and because we get UV__POLLOUT, we also try to write the queued send requests, and we succeed! so we call uv__io_feed again, to call its callback.
  • Since we're ietarting the pending queue, and uv__io_feed adds the handle to that very same queue, we enter an infinite loop.

I'll keep digging...

@saghul

saghul commented May 27, 2015

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Solved it! All tests pass, it was a fuckup in using QUEUE_FOREACH. @bnoordhuis can you PTAL?

@bnoordhuis

bnoordhuis commented May 27, 2015

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LGTM

@saghul
saghul merged commit 1816dbc into libuv:v1.x May 28, 2015
@saghul

saghul commented May 28, 2015

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Thanks Ben! Adjusted the comment and landed.

@saghul saghul mentioned this pull request May 28, 2015
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saghul added 2 commits May 28, 2015 11:05
@saghul
unix: prevent infinite loop in uv__run_pending
3ceb260 
If any of the callbacks called in uv__run_pending calls
uv__io_feed we enter an infinite loop, because we add the handle to the
same queue we are iterating over.

Refs: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
@saghul
unix: make sure UDP send callbacks are asynchronous
1816dbc 
Fixes: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
saghul added a commit to saghul/node that referenced this pull request Jun 3, 2015
@saghul
dgram: partially revert 18d457b
7456692 
Revert "dgram: call send callback asynchronously" partially, since the
fix is now done in libuv.

Refs: nodejs#1313
Refs: libuv/libuv#371
bnoordhuis pushed a commit to nodejs/node that referenced this pull request Jun 3, 2015
@saghul @bnoordhuis
dgram: partially revert 18d457b
b5cd2f0 
Revert "dgram: call send callback asynchronously" partially, since the
fix is now done in libuv.

Refs: #1313
Refs: libuv/libuv#371
PR-URL: #1889
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
guworks pushed a commit to guworks/libuv that referenced this pull request Jul 9, 2015
@saghul @guworks
unix: prevent infinite loop in uv__run_pending
331218e 
If any of the callbacks called in uv__run_pending calls
uv__io_feed we enter an infinite loop, because we add the handle to the
same queue we are iterating over.

Refs: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
guworks pushed a commit to guworks/libuv that referenced this pull request Jul 9, 2015
@saghul @guworks
unix: make sure UDP send callbacks are asynchronous
efcafdf 
Fixes: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
skomski pushed a commit to skomski/libuv that referenced this pull request Aug 5, 2015
@saghul @skomski
unix: prevent infinite loop in uv__run_pending
0a5cd56 
If any of the callbacks called in uv__run_pending calls
uv__io_feed we enter an infinite loop, because we add the handle to the
same queue we are iterating over.

Refs: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
skomski pushed a commit to skomski/libuv that referenced this pull request Aug 5, 2015
@saghul @skomski
unix: make sure UDP send callbacks are asynchronous
5c12f7c 
Fixes: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
skomski pushed a commit to skomski/libuv that referenced this pull request Aug 5, 2015
@saghul @skomski
unix: prevent infinite loop in uv__run_pending
a4e738a 
If any of the callbacks called in uv__run_pending calls
uv__io_feed we enter an infinite loop, because we add the handle to the
same queue we are iterating over.

Refs: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
skomski pushed a commit to skomski/libuv that referenced this pull request Aug 5, 2015
@saghul @skomski
unix: make sure UDP send callbacks are asynchronous
9d030ae 
Fixes: libuv#301
PR-URL: libuv#371
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
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udp: callbacks are effectively synchronous

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@saghul @bnoordhuis
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