This is an archive of the discontinued Mercurial Phabricator instance.

Differential D5588

watchman: disable fsmonitor when running non-interactively
AbandonedPublic

Authored by lothiraldan on Jan 15 2019, 11:57 AM.

Details

Reviewers
indygreg
Group Reviewers
hg-reviewers
Summary

One of the risks with activating fsmonitor globally is resource exhaustion
(like inotify watches on Linux).

When launching background-jobs, it's often better to not activate fsmonitor in
order to conserve resources for future interactive commands launched by users.

This can be overridden with the environment variable HGWATCHMAN_ENABLE

Diff Detail

Repository
rHG Mercurial
Lint
Lint Skipped
Unit
Unit Tests Skipped

Event Timeline

lothiraldan created this revision.Jan 15 2019, 11:57 AM
indygreg requested changes to this revision.Jan 16 2019, 2:50 PM
indygreg added a subscriber: indygreg.

Why wouldn't we want automated, non-interactive tools to have the benefits of watchman? There are plenty of use cases where complex Mercurial operations are scripted and would benefit from watchman.

Your commit message details an issue that I assume you encountered in the wild. Are there other ways we can work around this? Perhaps we can set the idle timeout/shutdown interval of watchman to be much smaller when Mercurial is non-interactive?

This revision now requires changes to proceed.Jan 16 2019, 2:50 PM
lothiraldan added a comment.Jan 17 2019, 11:35 AM
In D5588#82922, @indygreg wrote:

Why wouldn't we want automated, non-interactive tools to have the benefits of watchman? There are plenty of use cases where complex Mercurial operations are scripted and would benefit from watchman.
Your commit message details an issue that I assume you encountered in the wild. Are there other ways we can work around this? Perhaps we can set the idle timeout/shutdown interval of watchman to be much smaller when Mercurial is non-interactive?

Yes what we saw in the wild is background jobs taking all the resources making interactive commands slower for users.

I'm not sure what are the others workaround for this, I don't know if tuning the timeout / shutdown might be useful.

There is also the possibility to put it behind a config knob.

lothiraldan abandoned this revision.Feb 13 2019, 11:22 AM

Revision Contents
Changeset List

PathPackages
Mhgext/fsmonitor/__init__.py (21 lines)

Diff 14069

hgext/fsmonitor/__init__.py

default=False, default=False,
) )
configitem('fsmonitor', 'timeout', configitem('fsmonitor', 'timeout',
default='2', default='2',
) )
configitem('fsmonitor', 'blacklistusers', configitem('fsmonitor', 'blacklistusers',
default=list, default=list,
) )
configitem('fsmonitor', 'enable_on_non_interactive',
default=True,
)
configitem('fsmonitor', 'verbose', configitem('fsmonitor', 'verbose',
default=True, default=True,
) )
configitem('experimental', 'fsmonitor.transaction_notify', configitem('experimental', 'fsmonitor.transaction_notify',
default=False, default=False,
) )
# This extension is incompatible with the following blacklisted extensions # This extension is incompatible with the following blacklisted extensions
# We don't work with largefiles or inotify # We don't work with largefiles or inotify
exts = extensions.enabled() exts = extensions.enabled()
for ext in _blacklist: for ext in _blacklist:
if ext in exts: if ext in exts:
ui.warn(_('The fsmonitor extension is incompatible with the %s ' ui.warn(_('The fsmonitor extension is incompatible with the %s '
'extension and has been disabled.\n') % ext) 'extension and has been disabled.\n') % ext)
return return
enabled = None
if 'HGWATCHMAN_ENABLE' in encoding.environ:
enabled = encoding.environ['HGWATCHMAN_ENABLE'].lower()
if enabled == 'true' or enabled == '':
pass
elif enabled == 'false':
ui.debug('fsmonitor: disabled through HGWATCHMAN_ENABLE env variable')
return
else:
interactive = ui.interactive()
enable_on_non_interactive = ui.configbool(
'fsmonitor', 'enable_on_non_interactive'
)
if not interactive and not enable_on_non_interactive:
ui.debug('fsmonitor: disabled for non-interactive commands')
return
if repo.local(): if repo.local():
# We don't work with subrepos either. # We don't work with subrepos either.
# #
# if repo[None].substate can cause a dirstate parse, which is too # if repo[None].substate can cause a dirstate parse, which is too
# slow. Instead, look for a file called hgsubstate, # slow. Instead, look for a file called hgsubstate,
if repo.wvfs.exists('.hgsubstate') or repo.wvfs.exists('.hgsub'): if repo.wvfs.exists('.hgsubstate') or repo.wvfs.exists('.hgsub'):
return return