This describes tools and techniques that can identify memory leaks in Long running Python programs:

• Is it a Leak?
• Sources of Leaks
• A Bit About (C)Python Memory Management
  • Reference Counts
  • Garbage Collection
  • The Big Picture
  • CPython’s Object Allocator (pymalloc)

Here is a visualisation of memory allocators from top to bottom (from the Python source Objects/obmalloc.c):

    _____   ______   ______       ________
   [ int ] [ dict ] [ list ] ... [ string ]       Python core         |
+3 | <----- Object-specific memory -----> | <-- Non-object memory --> |
    _______________________________       |                           |
   [   Python's object allocator   ]      |                           |
+2 | ####### Object memory ####### | <------ Internal buffers ------> |
    ______________________________________________________________    |
   [          Python's raw memory allocator (PyMem_ API)          ]   |
+1 | <----- Python memory (under PyMem manager's control) ------> |   |
    __________________________________________________________________
   [    Underlying general-purpose allocator (ex: C library malloc)   ]
 0 | <------ Virtual memory allocated for the python process -------> |

   =========================================================================
    _______________________________________________________________________
   [                OS-specific Virtual Memory Manager (VMM)               ]
-1 | <--- Kernel dynamic storage allocation & management (page-based) ---> |
    __________________________________   __________________________________
   [                                  ] [                                  ]
-2 | <-- Physical memory: ROM/RAM --> | | <-- Secondary storage (swap) --> |

He found that the more HTTP client requests he did, the more memory his Node process would consume, but it was really slow.

[...] Then I ran Node with UMEM_DEBUG set to record various important information about the memory allocations

[...] Every hour, it grabbed the output of pmap -x and a core file and stored those in Joyent Manta

[...] In MDB there's a particularly helpful command ::findleaks that will show you the memory addresses and the stack traces for leaked memory, not unlike using valgrind, but without all the performance penalty.

[...] At this point we knew that we were looking for something in v0.10 that called MakeCallback but that didn't first have a HandleScope on the stack. I then worked up this simple DTrace script.

Key point: this isn’t (just) about PGP or SMTP, it’s email as a whole system:

Even after we replace PGP, encrypted email will remain unsafe. Here’s why:

• If messages can be sent in plaintext, they will be sent in plaintext.
• Metadata is as important as content, and email leaks it.
• Every archived message will eventually leak.
• Every long term secret will eventually leak.

Un ensemble de papiers très sales sont en train d’être publiés chez Disclose [...]
on y apprend les détails de la fourniture d’un système de surveillance français au gouvernement Egyptien d’Al-Sissi. [...]
On y apprend que Nexa Technologies, via sa filiale émiratie, Advanced Middle East Systems … Attendez, on s’arrête un instant, Advances Middle East Systems… A.M.E.Sys. Amesys quoi. Ça ne s’invente pas.
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on y apprend également que cette vente a été « validée » par le SBDU. [...]
Ce ministre de l’Économie, celui qui porte la responsabilité de la validation de ce dispositif [...] c’est Emmanuel Macron, c’est le Président de la République.