From: Juan Yescas <jyescas@google.com>
To: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@kernel.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
open list <linux-kernel@vger.kernel.org>,
"open list:MEMORY MANAGEMENT - CORE" <linux-mm@kvack.org>
Cc: jyescas@google.com, android-mm@google.com, ljs@kernel.org,
fvdl@google.com, tkjos@google.com, minchan@google.com,
dskiba@google.com, open list <linux-kernel@vger.kernel.org>,
"open list:MEMORY MANAGEMENT - CORE" <linux-mm@kvack.org>
Subject: [RFC PATCH v2 00/16] Page Alloc Hogger
Date: Wed, 5 Aug 2026 18:09:01 -0700 [thread overview]
Message-ID: <20260806011048.517229-1-jyescas@google.com> (raw)
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:
- Reproduce low-memory conditions: Easily trigger and inspect kernel
mechanisms like direct reclaim, kswapd, the OOM killer, and allocation
fallbacks.
- Simplify memory pressure debugging: Debug issues that only manifest under
memory stress without needing custom kernel drivers or userspace programs
to allocate memory.
- Simplify unit testing: Verify that memory management subsystems
(direct reclaim, OOM killer, kswapd) trigger as expected in test suites.
- Measure performance under stress: Evaluate how applications behave and
perform during severe memory pressure.
Usage:
1. To trigger the allocation, navigate to the debugfs path corresponding
to your target node, memory zone, allocation order, and migration type,
then write the requested allocation count to nr_pages_allocs.
For example, to make 3 allocs of order 9, Migrate Type Movable,
Zone Normal and Node 0, run:
$ echo 3 > /sys/kernel/debug/mm/node-0/zone-Normal/order-9/migrate-Movable/nr_pages_allocs
2. For each allocation created, a corresponding file named sequentially
(1, 2, n) will appear in that directory.
$ ls /sys/kernel/debug/mm/node-0/zone-Normal/order-9/migrate-Movable/
1 2 3 nr_pages_allocs
3. To free the allocation, write the allocation file name in
/sys/kernel/debug/mm/free. For example, to release the 2nd allocation run:
$ echo 2 > /sys/kernel/debug/mm/free
Example:
$ cat /proc/pagetypeinfo
Page block order: 9
Pages per block: 512
Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
Node 0, zone DMA, type Unmovable 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type Movable 1 1 1 0 1 1 2 2 1 3 732
Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type CMA 0 0 0 0 0 0 0 0 0 1 7
Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type Unmovable 13 7 0 1 0 0 1 0 1 0 0
Node 0, zone Normal, type Movable 1 1 1 1 1 1 1 0 1 1 1221
Node 0, zone Normal, type Reclaimable 1 0 0 0 0 0 1 0 0 1 0
Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type CMA 0 0 0 0 0 0 0 0 0 1 7
Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0
Number of blocks type Unmovable Movable Reclaimable HighAtomic CMA Isolate
Node 0, zone DMA 0 1520 0 0 16 0
Node 0, zone Normal 12 2530 2 0 16 0
$ echo 1200 > /sys/kernel/debug/mm/node-0/zone-Normal/order-10/migrate-Movable/nr_pages_allocs
$ cat /proc/pagetypeinfo
Page block order: 9
Pages per block: 512
Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
Node 0, zone DMA, type Unmovable 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type Movable 1 1 1 0 1 1 2 2 1 3 732
Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type CMA 0 0 0 0 0 0 0 0 0 1 7
Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type Unmovable 13 7 1 1 0 0 0 0 1 0 0
Node 0, zone Normal, type Movable 1 1 1 1 1 1 1 0 1 1 21
Node 0, zone Normal, type Reclaimable 0 1 0 0 1 0 0 0 1 0 0
Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type CMA 0 0 0 0 0 0 0 0 0 1 7
Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0
Number of blocks type Unmovable Movable Reclaimable HighAtomic CMA Isolate
Node 0, zone DMA 0 1520 0 0 16 0
Node 0, zone Normal 12 2530 2 0 16 0
$ for i in `seq 1 1200`; do echo $i > /sys/kernel/debug/mm/free; done
$ cat /proc/pagetypeinfo
Page block order: 9
Pages per block: 512
Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10
Node 0, zone DMA, type Unmovable 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type Movable 1 1 1 0 1 1 2 2 1 3 732
Node 0, zone DMA, type Reclaimable 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA, type CMA 0 0 0 0 0 0 0 0 0 1 7
Node 0, zone DMA, type Isolate 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type Unmovable 13 7 1 1 0 0 0 0 1 0 0
Node 0, zone Normal, type Movable 1 1 1 1 1 1 1 0 1 1 1221
Node 0, zone Normal, type Reclaimable 0 1 0 0 1 0 0 0 1 0 0
Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type CMA 0 0 0 0 0 0 0 0 0 1 7
Node 0, zone Normal, type Isolate 0 0 0 0 0 0 0 0 0 0 0
Number of blocks type Unmovable Movable Reclaimable HighAtomic CMA Isolate
Node 0, zone DMA 0 1520 0 0 16 0
Node 0, zone Normal 12 2530 2 0 16 0
Notes:
- The only zone that is not supported is ZONE_DEVICE.
- MIGRATE_CMA will be supported soon
Juan Yescas (16):
mm: Page Alloc Hogger module
mm: Define structs for allocation requests and store allocations
mm: Define the caches for the structs req_alloc and page_alloc
mm: Define function to create a dir for each online node
mm: Define function to create a dir for populated zone
mm: Define function to create a dir for each page order
mm: Define function to create a dir for each migrate type
mm: Define function that creates the "nr_pages_allocs" file
mm: Read the nr_pages_allocs value given by user
mm: Set the selected zone in gfp_t flags
mm: Sets the migrate type in gfp_t flags
mm: Define the make_alloc() function
mm: Create the file associated with an allocation
mm: Free pages, remove files and clean cache when one alloc fails
mm: Create the "free" file to release the previously allocated pages
mm: Release resources when the page alloc hogger module exits
mm/Kconfig.debug | 12 +
mm/Makefile | 1 +
mm/page_alloc_hogger.c | 610 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 623 insertions(+)
create mode 100644 mm/page_alloc_hogger.c
--
2.55.0.629.g250fe7f194-goog
next reply other threads:[~2026-08-06 1:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-06 1:09 Juan Yescas [this message]
2026-08-06 1:09 ` [RFC PATCH v2 01/16] mm: Page Alloc Hogger module Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 02/16] mm: Define structs for allocation requests and store allocations Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 03/16] mm: Define the caches for the structs req_alloc and page_alloc Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 04/16] mm: Define function to create a dir for each online node Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 05/16] mm: Define function to create a dir for populated zone Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 06/16] mm: Define function to create a dir for each page order Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 07/16] mm: Define function to create a dir for each migrate type Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 08/16] mm: Define function that creates the "nr_pages_allocs" file Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 09/16] mm: Read the nr_pages_allocs value given by user Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 10/16] mm: Set the selected zone in gfp_t flags Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 11/16] mm: Sets the migrate type " Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 12/16] mm: Define the make_alloc() function Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 13/16] mm: Create the file associated with an allocation Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 14/16] mm: Free pages, remove files and clean cache when one alloc fails Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 15/16] mm: Create the "free" file to release the previously allocated pages Juan Yescas
2026-08-06 1:09 ` [RFC PATCH v2 16/16] mm: Release resources when the page alloc hogger module exits Juan Yescas
2026-08-06 5:22 ` [RFC PATCH v2 00/16] Page Alloc Hogger Andrew Morton
2026-08-06 9:48 ` Lorenzo Stoakes (ARM)
2026-08-06 11:17 ` David Hildenbrand (Arm)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260806011048.517229-1-jyescas@google.com \
--to=jyescas@google.com \
--cc=Liam.Howlett@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=android-mm@google.com \
--cc=david@kernel.org \
--cc=dskiba@google.com \
--cc=fvdl@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=lorenzo.stoakes@oracle.com \
--cc=mhocko@suse.com \
--cc=minchan@google.com \
--cc=rppt@kernel.org \
--cc=surenb@google.com \
--cc=tkjos@google.com \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox