[tracker/sam/faq-memory] website/faq: Add note about RAM usage

[Sam Thursfield <sthursfield src gnome org>]

commit 1d5818d0bdd511ed5015add6fb7bcda4cadcab5c
Author: Sam Thursfield <sam afuera me uk>
Date:   Sat Oct 31 13:27:05 2020 +0100

    website/faq: Add note about RAM usage

 docs/website/faq.md | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/docs/website/faq.md b/docs/website/faq.md
index ec4f9a0fc..c7b574ade 100644
--- a/docs/website/faq.md
+++ b/docs/website/faq.md
@@ -58,6 +58,14 @@ if there was an error while indexing. Use this command:
 
 ## Why does Tracker consume resources on my PC?
 
+Memory management in Linux is [complex](http://opsmonkey.blogspot.com/2007/01/linux-memory-overcommit.html).
+It's normal that processes may appear to use 1GB or more of RAM -- this number
+doesn't directly correspond to physical memory, and it's only a problem if you
+get to a low-memory situation and the kernel is unable to
+reclaim the memory. Tracker Miner FS integrates with the [low-memory-monitor 
service](https://www.hadess.net/2019/08/low-memory-monitor-new-project.html)
+when it's available, and has a [30 second 
timeout](https://gitlab.gnome.org/GNOME/tracker-miners/-/commit/ccb0b4ebbff4dfacf17ea67ce56bb27c39741811)
+that asks the system to reclaim the spare memory when indexing is finished.
+
 When you add or edit files, Tracker Miner FS will update its index. This should
 be very quick, but if a huge number of files are added then it may cause
 noticably high CPU and IO usage until the new files have been indexed. This is