view contrib/memory.py @ 33087:fcd1c483f5ea

strip: add a delayedstrip method that works in a transaction

For long, the fact that strip does not work inside a transaction and some
code has to work with both obsstore and fallback to strip lead to duplicated
code like:

      with repo.transaction():
          ....
          if obsstore:
              obsstore.createmarkers(...)
      if not obsstore:
          repair.strip(...)

Things get more complex when you want to call something which may call strip
under the hood. Like you cannot simply write:

      with repo.transaction():
          ....
          rebasemod.rebase(...) # may call "strip", so this doesn't work

But you do want rebase to run inside a same transaction if possible, so the
code may look like:

      with repo.transaction():
          ....
          if obsstore:
              rebasemod.rebase(...)
              obsstore.createmarkers(...)
      if not obsstore:
          rebasemod.rebase(...)
          repair.strip(...)

That's ugly and error-prone. Ideally it's possible to just write:

      with repo.transaction():
          rebasemod.rebase(...)
          saferemovenodes(...)

This patch is the first step towards that. It adds a "delayedstrip" method
to repair.py which maintains a postclose callback in the transaction object.

# memory.py - track memory usage
#
# Copyright 2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

'''helper extension to measure memory usage

Reads current and peak memory usage from ``/proc/self/status`` and
prints it to ``stderr`` on exit.
'''

from __future__ import absolute_import

def memusage(ui):
    """Report memory usage of the current process."""
    result = {'peak': 0, 'rss': 0}
    with open('/proc/self/status', 'r') as status:
        # This will only work on systems with a /proc file system
        # (like Linux).
        for line in status:
            parts = line.split()
            key = parts[0][2:-1].lower()
            if key in result:
                result[key] = int(parts[1])
    ui.write_err(", ".join(["%s: %.1f MiB" % (k, v / 1024.0)
                            for k, v in result.iteritems()]) + "\n")

def extsetup(ui):
    ui.atexit(memusage, ui)