Re: [RFC PATCH v2 00/16] Page Alloc Hogger

[Andrew Morton]

On Wed,  5 Aug 2026 18:09:01 -0700 Juan Yescas <jyescas@xxxxxxxxxx> wrote:

> This patch series introduces the Page Alloc Hogger. The Page Alloc Hogger
> allows you to allocate memory pages from specific nodes, zones, migration
> types, and orders directly via debugfs. This provides key benefits for
> testing and debugging:

OK, so this is targeted at kernel developers.  And they may indeed find
it useful.  I see value in us developing a common way for developers to
apply well-targeted stress to MM.


Probably everyone has their own favorite memory stresstest suite.  Most
of these will be in userspace[*] but I see there is merit in doing it
in-kernel.  Any perspective you can add to this choice would be
interesting?


Some usage scenarioizing would help.  Is this being used within google?
If so, for what purpose and with what results?  Sell it to us - help
your audience understand what benefit it offers to them.


If this proposal has legs then we should Document/ it separately - that
big block comment in page_alloc_hogger.c will become unweildy.


One could consider plumbing this into selftests/ in some fashion, but I
wouldn't encourage that - longrunning torture tests aren't appropriate
for selftests, which are nice and snappy.  Perhaps a new
tools/testing/stresstests will one day appear.



> +obj-$(CONFIG_PAGEALLOC_HOGGER) += page_alloc_hogger.o

page_alloc or pagealloc.  Choose only one, lest you drive people crazy
for ever.



Sashiko went totally nuts.  Have fun with that ;) But I wouldn't do a
ton of work on this until you've heard positive noises from the MM team,
Guys, poke.  wdyt, is there potential here?

	https://sashiko.dev/#/patchset/20260806011048.517229-1-jyescas@xxxxxxxxxx


[*] Back in the days when I was trying to get redhat ext3 and 2.5.x
    MM to do something other than lock up or crash, I wrote a userspace
    thing called "usemem".  In recent times I've seen people quoting
    usemem results and wondered "is that my thing".  So I looked it up.
    It is!  And it's now quite unrecognizable.

    Because, obviously, people found it useful and so they used it
    and added to it and added to it and more.

    And I expect the same will occur with "Page Alloc Hogger"
    (terrible name, btw.  How about "pagehog"?  "memhog"), if it is
    adopted.  People will use it and will add to it.