Linux pagecache.Files: Memory Usage

[dgmcdona]

Converts objects.Pointer to int before storing them in the set. This
should have a substantial impact on memory, similar to those in #1758

[dgmcdona]

On second thought, the calls to int() for seen_dentries may not be necessary since dentry.vol.offset is just an int already, but maybe good to leave it explicit?

[ikelos]

Looks good, although, please could we add a couple comments to explain why we're casting in this specific instance when we normally go to great lengths to get people not to cast (so that they don't lose useful information or litter the code with unnecessary casts)...

[ikelos]

Out of interest, does the if root_inode_ptr in seen_inodes: still work, if the entries in seen_inodes are all ints? Just curious to know whether it does object comparison or runs the equality tests on them (and whether our equality test says they're the same). Either way I'm happy with this, but I'll hold off until we get the answer, just in case we can trim one of the casts...

[dgmcdona]

Looks like the call to __hash__ returns the same value for both, and the equality test passes:

[ins] In [1]: seen = set()

[ins] In [2]: seen.add(int(root_inode_ptr))

[ins] In [3]: seen
Out[3]: {175402173655680}

[ins] In [4]: root_inode_ptr in seen
Out[4]: True

[ins] In [5]: root_inode_ptr.__class__
Out[5]: volatility3.framework.objects.Pointer

[ins] In [6]: hash(root_inode_ptr)
Out[6]: 175402173655680

[ins] In [7]: hash(int(root_inode_ptr))
Out[7]: 175402173655680

[ins] In [8]: int(root_inode_ptr) == root_inode_ptr
Out[8]: True

[dgmcdona]

Removed the unneeded casts in a236c0d