686720 - Expose /proc/smaps PSS in about:memory

Status: RESOLVED FIXED

(Toolkit :: about:memory, defect)

Description

[Justin Lebar (not reading bugmail)]

For each mapping, smaps gives us an RSS and additionally a "proportional set size" (PSS).  A page's PSS is its RSS divided by the number of processes which have that page mapped.

I'd originally hidden PSS in about:memory, since on desktop, it's different from RSS only for shared libraries.  It's not so interesting.

But on mobile, PSS is much more interesting, because it shows us how much memory we're sharing between the content and chrome processes.  So I think we should just show PSS; it'll be collapsed by default anyway.

Comment 1

[Justin Lebar (not reading bugmail)]

See http://lxr.linux.no/#linux+v3.0.4/fs/proc/task_mmu.c#L344

Comment 2

[Justin Lebar (not reading bugmail)]

Attachment: Patch v1

Comment 3

[Kyle Huey (Exited; not receiving bugmail, old account, do not use)]

Comment on attachment 560412 [details] [diff] [review]
Patch v1

This looks fine, but it looks like the original that you made the diff against was weird ...

Comment 4

[Justin Lebar (not reading bugmail)]

Yeah, it looks like I somehow managed to include hunks from another patch in here.

I'll figure it out before I push.  Thanks.

Comment 5

[(no longer active)]

https://hg.mozilla.org/mozilla-central/rev/bbf7bdb0c75f