[Hero, G2 Touch Android Development] androcheck:
UPDATE to make more clear what these 6 values mean, when you enter a command like this:

echo "1536,2048,4096,5120,15360,23040" > /sys/module/lowmemorykiller/parameters/minfree
[B] #1 #2 #3 #4 #5 #6[/B]

Important

: The unit of these numbers are "pages" (1 page = 4 kilobyte)

These define 6 limits of minimum "available" memory (which is not necessary equivalent to "free" memory under Linux, but this is an other story). These 6 limits are associated with 6 categories of processes under Android.

If the available memory goes below one of these limits, the kernel starts to kill processes of the corresponding category.

On Android the "ActivityManagerService" takes care of assigning processes into one of these categories (which means nothing more than setting an appropriate "oom_adj" value).

Details on the 6 categories:

#1: FOREGROUND_APP:

Only the current application in the foreground. This is the activity that is the focus for the user's actions.​

#2: VISIBLE_APP:

Applications which are not in the foreground but are still visble to the user. That is, another activity lies on top of it and that activity either is transparent or doesn't cover the full screen.​

#3: SECONDARY_SERVER:

First: The "HOME" application (or SenseUI on Hero) also falls into this category! So do not set this limit to high!

Further: All (secondary) services, which are currently running. These are all normal services as we know them from applications. ("Primary" services are life-critical services like the PhoneService which never will get killed by the lowmemorykiller.) ​

#4: HIDDEN_APP:

Any other Activity which falls not under #1 or #2. So any Activity as soon as it is not visible anymore (i.e. in the background, because of pressing Home, or starting another Activity).​

#5: CONTENT_PROVIDER:

Processes which host a content provider that does not have any clients connected to it.

For explanation: Content providers store and retrieve data and make it accessible to all applications. Examples are: the contacts content provider, the calendar content provider, the sms content provider, and so on. These allow different applications to access the same underlying data (contacts, calendar, ...).​

#6: EMPTY_APP:

This is a process without anything currently running in it. On Android a prgrammer can call "finish()" to close an activity. The system still can decide to keep the "empty" process running, to avoid the startup overhead when the user needs the activity again. All processes in this group are empty processes.​

So, to sum up a little bit:

I definitely would be careful with the first 3 values, as they may affect directly the user experience! But it seems there is a wider range of settings we can try at the last 3 values. These applications could be safely killed. So try around until you find appropriate values for your needs. :)

As long as you just perform the "echo ..." command and do not change any startup script or something like this you should be on the safe side. If something goes wrong, just restart your phone and everything should be normal again.

Hope that helps.. ;)

[edit]

All said about this should apply to any Android device. Not only the Hero and not only Android 1.5. So try it also on Eclair! :)

[/edit]