[Geany-devel] Geany memory behavior "suspected memory leak - ID: 3415254"

Lex Trotman elextr at xxxxx
Fri Oct 14 03:09:02 UTC 2011

Hi All,

I have been investigating bug report "suspected memory leak - ID:
3415254" and have gathered the following data (before my patience ran
out).  The tests reported here are with Git 55646df8 unless otherwise

Geany left all day without any activity (with files open) did not
increase in memory usage (and the same with 0.20, the reported

I then tried opening and closing geany/src/* repeatedly.  The
following table shows Geany memory usage (in Mb) when all files are
closed and when all open and the difference.  The last column shows
that the first two times extra memory was used to tab through all the
open files, but after that no more was used.

closed open delta tabbing
 5.1   27.9  22.8   1.1
28.8   31.2   0.4   1.1
32.1   33.0   0.9   0.0
32.8   34.8   2.0   0.0
34.6   35.9   1.3   0.0
35.7   36.4   0.7   0.0
36.2   37.4   1.2   0.0
37.2   38.1   0.9   0.0
37.9   41.8   2.9   0.0
41.6   42.3   0.7   0.0
42.0   42.8   0.8   0.0
42.6   43.3   0.7   0.0
43.1   44.3   1.2   0.0
44.1   44.7   0.4   0.0
44.5   45.7   1.2   0.0

To me the key points are:

1. each time all files are closed only 200k is returned to the OS, but
since the first open uses 22.8Mb but later ones less, Geany isn't
leaking all of it, it is being held by the allocators.

2. ignoring the first open, the amount of extra memory used to open
all the files varied from 0.4Mb to 2.9Mb.  Average 1.1Mb or 5% of the
initial 22.8Mb and standard deviation of 0.665Mb or 3% of the 22.8Mb.

3. Simple leaks are unlikely to cause the large deviation in the
memory increase, each open of the same set of files would tend to leak
the same amount.  It is therefore likely that fragmentation effects
cause the large deviation, but it may not be the whole cause of the

Since Geany uses three different allocators, each of which has
differing policies for holding onto memory, it is going to be
difficult to separate real leaks from allocator effects.

For the bug reporter to have accumulated 300Mb of memory over "a few"
days would have needed about 500 file opens per day, but maybe
somewhat less as editing increases the memory usage.

So I don't think we have to worry excessively that we have a major
leak, but keep an eye open for any possible problems.

Note that all my testing was with no plugins and only a couple of
filetypes.  There may be leaks and other effects in plugins and/or
other Scintilla lexers.  If the OP posts more information we may know


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