From: Fabio Estevam <festevam(a)denx.de>
Since commit 559358282e5b ("drm/fb-helper: Don't use the preferred depth
for the BPP default"), RGB565 displays such as the CFAF240320X no longer
render correctly: colors are distorted and the content is shown twice
horizontally.
This regression is due to the fbdev emulation layer defaulting to 32 bits
per pixel, whereas the display expects 16 bpp (RGB565). As a result, the
framebuffer data is incorrectly interpreted by the panel.
Fix the issue by calling drm_client_setup_with_fourcc() with a format
explicitly selected based on the display's bits-per-pixel value. For 16
bpp, use DRM_FORMAT_RGB565; for other values, fall back to the previous
behavior. This ensures that the allocated framebuffer format matches the
hardware expectations, avoiding color and layout corruption.
Tested on a CFAF240320X display with an RGB565 configuration, confirming
correct colors and layout after applying this patch.
Cc: stable(a)vger.kernel.org
Fixes: 559358282e5b ("drm/fb-helper: Don't use the preferred depth for the BPP default")
Signed-off-by: Fabio Estevam <festevam(a)denx.de>
Reviewed-by: Thomas Zimmermann <tzimmermann(a)suse.de>
---
Changes since v1:
- Improved the commit log.
- Added Thomas' Reviewed-by tag.
- Added more maintainers on Cc as panel-mipi-dbi.c has been marked as orphan.
drivers/gpu/drm/tiny/panel-mipi-dbi.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/tiny/panel-mipi-dbi.c b/drivers/gpu/drm/tiny/panel-mipi-dbi.c
index 0460ecaef4bd..23914a9f7fd3 100644
--- a/drivers/gpu/drm/tiny/panel-mipi-dbi.c
+++ b/drivers/gpu/drm/tiny/panel-mipi-dbi.c
@@ -390,7 +390,10 @@ static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
spi_set_drvdata(spi, drm);
- drm_client_setup(drm, NULL);
+ if (bpp == 16)
+ drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB565);
+ else
+ drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB888);
return 0;
}
--
2.34.1
Commit 60e3318e3e900 ("cifs: use fs_context for automounts") was
released in v6.1.54 and broke the failover when one of the servers
inside DFS becomes unavailable. We reproduced the problem on the EC2
instances of different types. Reverting aforementioned commint on top of
the latest stable verison v6.1.94 helps to resolve the problem.
Earliest working version is v6.2-rc1. There were two big merges of CIFS fixes:
[1] and [2]. We would like to ask for the help to investigate this problem and
if some of those patches need to be backported. Also, is it safe to just revert
problematic commit until proper fixes/backports will be available?
We will help to do testing and confirm if fix works, but let me also list the
steps we used to reproduce the problem if it will help to identify the problem:
1. Create Active Directory domain eg. 'corp.fsxtest.local' in AWS Directory
Service with:
- three AWS FSX file systems filesystem1..filesystem3
- three Windows servers; They have DFS installed as per
https://learn.microsoft.com/en-us/windows-server/storage/dfs-namespaces/dfs…:
- dfs-srv1: EC2AMAZ-2EGTM59
- dfs-srv2: EC2AMAZ-1N36PRD
- dfs-srv3: EC2AMAZ-0PAUH2U
2. Create DFS namespace eg. 'dfs-namespace' in Windows server 2008 mode
and three folders targets in it:
- referral-a mapped to filesystem1.corp.local
- referral-b mapped to filesystem2.corp.local
- referral-c mapped to filesystem3.corp.local
- local folders dfs-srv1..dfs-srv3 in C:\DFSRoots\dfs-namespace of every
Windows server. This helps to quickly define underlying server when
DFS is mounted.
3. Enabled cifs debug logs:
```
echo 'module cifs +p' > /sys/kernel/debug/dynamic_debug/control
echo 'file fs/cifs/* +p' > /sys/kernel/debug/dynamic_debug/control
echo 7 > /proc/fs/cifs/cifsFYI
```
4. Mount DFS namespace on Amazon Linux 2023 instance running any vanilla
kernel v6.1.54+:
```
dmesg -c &>/dev/null
cd /mnt
mount -t cifs -o cred=/mnt/creds,echo_interval=5 \
//corp.fsxtest.local/dfs-namespace \
./dfs-namespace
```
5. List DFS root, it's also required to avoid recursive mounts that happen
during regular 'ls' run:
```
sh -c 'ls dfs-namespace'
dfs-srv2 referral-a referral-b
```
The DFS server is EC2AMAZ-1N36PRD, it's also listed in mount:
```
[root@ip-172-31-2-82 mnt]# mount | grep dfs
//corp.fsxtest.local/dfs-namespace on /mnt/dfs-namespace type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.11.26,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1)
//EC2AMAZ-1N36PRD.corp.fsxtest.local/dfs-namespace/referral-a on /mnt/dfs-namespace/referral-a type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.12.80,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1)
```
List files in first folder:
```
sh -c 'ls dfs-namespace/referral-a'
filea.txt.txt
```
6. Shutdown DFS server-2.
List DFS root again, server changed from dfs-srv2 to dfs-srv1 EC2AMAZ-2EGTM59:
```
sh -c 'ls dfs-namespace'
dfs-srv1 referral-a referral-b
```
7. Try to list files in another folder, this causes ls to fail with error:
```
sh -c 'ls dfs-namespace/referral-b'
ls: cannot access 'dfs-namespace/referral-b': No route to host```
Sometimes it's also 'Operation now in progress' error.
mount shows the same output:
```
//corp.fsxtest.local/dfs-namespace on /mnt/dfs-namespace type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.11.26,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1)
//EC2AMAZ-1N36PRD.corp.fsxtest.local/dfs-namespace/referral-a on /mnt/dfs-namespace/referral-a type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.12.80,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1)
```
I also attached kernel debug logs from this test.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?…
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?…
Reported-by: Andrei Paniakin <apanyaki(a)amazon.com>
Bisected-by: Simba Bonga <simbarb(a)amazon.com>
---
#regzbot introduced: v6.1.54..v6.2-rc1
The PMIC GLINK driver is currently generating DisplayPort hotplug
notifications whenever something is connected to (or disconnected from)
a port regardless of the type of notification sent by the firmware.
These notifications are forwarded to user space by the DRM subsystem as
connector "change" uevents:
KERNEL[1556.223776] change /devices/platform/soc(a)0/ae00000.display-subsystem/ae01000.display-controller/drm/card0 (drm)
ACTION=change
DEVPATH=/devices/platform/soc(a)0/ae00000.display-subsystem/ae01000.display-controller/drm/card0
SUBSYSTEM=drm
HOTPLUG=1
CONNECTOR=36
DEVNAME=/dev/dri/card0
DEVTYPE=drm_minor
SEQNUM=4176
MAJOR=226
MINOR=0
On the Lenovo ThinkPad X13s and T14s, the PMIC GLINK firmware sends two
identical notifications with orientation information when connecting a
charger, each generating a bogus DRM hotplug event. On the X13s, two
such notification are also sent every 90 seconds while a charger remains
connected, which again are forwarded to user space:
port = 1, svid = ff00, mode = 255, hpd_state = 0
payload = 01 00 00 00 00 00 00 ff 00 00 00 00 00 00 00 00
Note that the firmware only sends on of these when connecting an
ethernet adapter.
Fix the spurious hotplug events by only forwarding hotplug notifications
for the Type-C DisplayPort service id. This also reduces the number of
uevents from four to two when an actual DisplayPort altmode device is
connected:
port = 0, svid = ff01, mode = 2, hpd_state = 0
payload = 00 01 02 00 f2 0c 01 ff 03 00 00 00 00 00 00 00
port = 0, svid = ff01, mode = 2, hpd_state = 1
payload = 00 01 02 00 f2 0c 01 ff 43 00 00 00 00 00 00 00
Fixes: 080b4e24852b ("soc: qcom: pmic_glink: Introduce altmode support")
Cc: stable(a)vger.kernel.org # 6.3
Cc: Bjorn Andersson <andersson(a)kernel.org>
Reported-by: Clayton Craft <clayton(a)craftyguy.net>
Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org>
---
Clayton reported seeing display flickering with recent RC kernels, which
may possibly be related to these spurious events being generated with
even greater frequency.
That still remains to be fully understood, but the spurious events, that
on the X13s are generated every 90 seconds, should be fixed either way.
Johan
drivers/soc/qcom/pmic_glink_altmode.c | 30 +++++++++++++++++----------
1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c
index bd06ce161804..7f11acd33323 100644
--- a/drivers/soc/qcom/pmic_glink_altmode.c
+++ b/drivers/soc/qcom/pmic_glink_altmode.c
@@ -218,21 +218,29 @@ static void pmic_glink_altmode_worker(struct work_struct *work)
{
struct pmic_glink_altmode_port *alt_port = work_to_altmode_port(work);
struct pmic_glink_altmode *altmode = alt_port->altmode;
+ enum drm_connector_status conn_status;
typec_switch_set(alt_port->typec_switch, alt_port->orientation);
- if (alt_port->svid == USB_TYPEC_DP_SID && alt_port->mode == 0xff)
- pmic_glink_altmode_safe(altmode, alt_port);
- else if (alt_port->svid == USB_TYPEC_DP_SID)
- pmic_glink_altmode_enable_dp(altmode, alt_port, alt_port->mode,
- alt_port->hpd_state, alt_port->hpd_irq);
- else
- pmic_glink_altmode_enable_usb(altmode, alt_port);
+ if (alt_port->svid == USB_TYPEC_DP_SID) {
+ if (alt_port->mode == 0xff) {
+ pmic_glink_altmode_safe(altmode, alt_port);
+ } else {
+ pmic_glink_altmode_enable_dp(altmode, alt_port,
+ alt_port->mode,
+ alt_port->hpd_state,
+ alt_port->hpd_irq);
+ }
- drm_aux_hpd_bridge_notify(&alt_port->bridge->dev,
- alt_port->hpd_state ?
- connector_status_connected :
- connector_status_disconnected);
+ if (alt_port->hpd_state)
+ conn_status = connector_status_connected;
+ else
+ conn_status = connector_status_disconnected;
+
+ drm_aux_hpd_bridge_notify(&alt_port->bridge->dev, conn_status);
+ } else {
+ pmic_glink_altmode_enable_usb(altmode, alt_port);
+ }
pmic_glink_altmode_request(altmode, ALTMODE_PAN_ACK, alt_port->index);
}
--
2.48.1
Some of our devices crash in tb_cfg_request_dequeue():
general protection fault, probably for non-canonical address 0xdead000000000122
CPU: 6 PID: 91007 Comm: kworker/6:2 Tainted: G U W 6.6.65
RIP: 0010:tb_cfg_request_dequeue+0x2d/0xa0
Call Trace:
<TASK>
? tb_cfg_request_dequeue+0x2d/0xa0
tb_cfg_request_work+0x33/0x80
worker_thread+0x386/0x8f0
kthread+0xed/0x110
ret_from_fork+0x38/0x50
ret_from_fork_asm+0x1b/0x30
The circumstances are unclear, however, the theory is that
tb_cfg_request_work() can be scheduled twice for a request:
first time via frame.callback from ring_work() and second
time from tb_cfg_request(). Both times kworkers will execute
tb_cfg_request_dequeue(), which results in double list_del()
from the ctl->request_queue (the list poison deference hints
at it: 0xdead000000000122).
Do not dequeue requests that don't have TB_CFG_REQUEST_ACTIVE
bit set.
Signed-off-by: Sergey Senozhatsky <senozhatsky(a)chromium.org>
Cc: stable(a)vger.kernel.org
---
v3: tweaked commit message
drivers/thunderbolt/ctl.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/thunderbolt/ctl.c b/drivers/thunderbolt/ctl.c
index cd15e84c47f4..1db2e951b53f 100644
--- a/drivers/thunderbolt/ctl.c
+++ b/drivers/thunderbolt/ctl.c
@@ -151,6 +151,11 @@ static void tb_cfg_request_dequeue(struct tb_cfg_request *req)
struct tb_ctl *ctl = req->ctl;
mutex_lock(&ctl->request_queue_lock);
+ if (!test_bit(TB_CFG_REQUEST_ACTIVE, &req->flags)) {
+ mutex_unlock(&ctl->request_queue_lock);
+ return;
+ }
+
list_del(&req->list);
clear_bit(TB_CFG_REQUEST_ACTIVE, &req->flags);
if (test_bit(TB_CFG_REQUEST_CANCELED, &req->flags))
--
2.49.0.395.g12beb8f557-goog
Hi,
After updating to 6.14.2, the ethernet adapter is almost unusable, I get
over 30% packet loss.
Bisect says it's this commit:
commit 85f6414167da39e0da30bf370f1ecda5a58c6f7b
Author: Vitaly Lifshits <vitaly.lifshits(a)intel.com>
Date: Thu Mar 13 16:05:56 2025 +0200
e1000e: change k1 configuration on MTP and later platforms
[ Upstream commit efaaf344bc2917cbfa5997633bc18a05d3aed27f ]
Starting from Meteor Lake, the Kumeran interface between the integrated
MAC and the I219 PHY works at a different frequency. This causes sporadic
MDI errors when accessing the PHY, and in rare circumstances could lead
to packet corruption.
To overcome this, introduce minor changes to the Kumeran idle
state (K1) parameters during device initialization. Hardware reset
reverts this configuration, therefore it needs to be applied in a few
places.
Fixes: cc23f4f0b6b9 ("e1000e: Add support for Meteor Lake")
Signed-off-by: Vitaly Lifshits <vitaly.lifshits(a)intel.com>
Tested-by: Avigail Dahan <avigailx.dahan(a)intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen(a)intel.com>
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
drivers/net/ethernet/intel/e1000e/defines.h | 3 ++
drivers/net/ethernet/intel/e1000e/ich8lan.c | 80 +++++++++++++++++++++++++++--
drivers/net/ethernet/intel/e1000e/ich8lan.h | 4 ++
3 files changed, 82 insertions(+), 5 deletions(-)
My system is Novacustom V540TU laptop with Intel Core Ultra 5 125H. And
the e1000e driver is running in a Xen HVM (with PCI passthrough).
Interestingly, I have also another one with Intel Core Ultra 7 155H
where the issue does not happen. I don't see what is different about
network adapter there, they look identical on lspci (but there are
differences about other devices)...
I see the commit above was already backported to other stable branches
too...
#regzbot introduced: 85f6414167da39e0da30bf370f1ecda5a58c6f7b
--
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
With UBSAN enabled, we're getting the following trace:
UBSAN: array-index-out-of-bounds in .../drivers/clk/clk-s2mps11.c:186:3
index 0 is out of range for type 'struct clk_hw *[] __counted_by(num)' (aka 'struct clk_hw *[]')
This is because commit f316cdff8d67 ("clk: Annotate struct
clk_hw_onecell_data with __counted_by") annotated the hws member of
that struct with __counted_by, which informs the bounds sanitizer about
the number of elements in hws, so that it can warn when hws is accessed
out of bounds.
As noted in that change, the __counted_by member must be initialised
with the number of elements before the first array access happens,
otherwise there will be a warning from each access prior to the
initialisation because the number of elements is zero. This occurs in
s2mps11_clk_probe() due to ::num being assigned after ::hws access.
Move the assignment to satisfy the requirement of assign-before-access.
Cc: stable(a)vger.kernel.org
Fixes: f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by")
Signed-off-by: André Draszik <andre.draszik(a)linaro.org>
---
drivers/clk/clk-s2mps11.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/clk-s2mps11.c b/drivers/clk/clk-s2mps11.c
index 014db6386624071e173b5b940466301d2596400a..8ddf3a9a53dfd5bb52a05a3e02788a357ea77ad3 100644
--- a/drivers/clk/clk-s2mps11.c
+++ b/drivers/clk/clk-s2mps11.c
@@ -137,6 +137,8 @@ static int s2mps11_clk_probe(struct platform_device *pdev)
if (!clk_data)
return -ENOMEM;
+ clk_data->num = S2MPS11_CLKS_NUM;
+
switch (hwid) {
case S2MPS11X:
s2mps11_reg = S2MPS11_REG_RTC_CTRL;
@@ -186,7 +188,6 @@ static int s2mps11_clk_probe(struct platform_device *pdev)
clk_data->hws[i] = &s2mps11_clks[i].hw;
}
- clk_data->num = S2MPS11_CLKS_NUM;
of_clk_add_hw_provider(s2mps11_clks->clk_np, of_clk_hw_onecell_get,
clk_data);
---
base-commit: 9388ec571cb1adba59d1cded2300eeb11827679c
change-id: 20250326-s2mps11-ubsan-c90978e7bc04
Best regards,
--
André Draszik <andre.draszik(a)linaro.org>
From: Fabio Estevam <festevam(a)denx.de>
Since commit 2718f15403fb ("iio: sanity check available_scan_masks array"),
verbose and misleading warnings are printed for devices like the MAX11601:
max1363 1-0064: available_scan_mask 8 subset of 0. Never used
max1363 1-0064: available_scan_mask 9 subset of 0. Never used
max1363 1-0064: available_scan_mask 10 subset of 0. Never used
max1363 1-0064: available_scan_mask 11 subset of 0. Never used
max1363 1-0064: available_scan_mask 12 subset of 0. Never used
max1363 1-0064: available_scan_mask 13 subset of 0. Never used
...
[warnings continue]
Fix the available_scan_masks sanity check logic so that it
only prints the warning when an element of available_scan_mask
is in fact a subset of a previous one.
These warnings incorrectly report that later scan masks are subsets of
the first one, even when they are not. The issue lies in the logic that
checks for subset relationships between scan masks.
Fix the subset detection to correctly compare each mask only
against previous masks, and only warn when a true subset is found.
With this fix, the warning output becomes both correct and more
informative:
max1363 1-0064: Mask 7 (0xc) is a subset of mask 6 (0xf) and will be ignored
Cc: stable(a)vger.kernel.org
Fixes: 2718f15403fb ("iio: sanity check available_scan_masks array")
Signed-off-by: Fabio Estevam <festevam(a)denx.de>
---
drivers/iio/industrialio-core.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 6a6568d4a2cb..855d5fd3e6b2 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1904,6 +1904,11 @@ static int iio_check_extended_name(const struct iio_dev *indio_dev)
static const struct iio_buffer_setup_ops noop_ring_setup_ops;
+static int is_subset(unsigned long a, unsigned long b)
+{
+ return (a & ~b) == 0;
+}
+
static void iio_sanity_check_avail_scan_masks(struct iio_dev *indio_dev)
{
unsigned int num_masks, masklength, longs_per_mask;
@@ -1947,21 +1952,13 @@ static void iio_sanity_check_avail_scan_masks(struct iio_dev *indio_dev)
* available masks in the order of preference (presumably the least
* costy to access masks first).
*/
- for (i = 0; i < num_masks - 1; i++) {
- const unsigned long *mask1;
- int j;
- mask1 = av_masks + i * longs_per_mask;
- for (j = i + 1; j < num_masks; j++) {
- const unsigned long *mask2;
-
- mask2 = av_masks + j * longs_per_mask;
- if (bitmap_subset(mask2, mask1, masklength))
+ for (i = 1; i < num_masks; ++i)
+ for (int j = 0; j < i; ++j)
+ if (is_subset(av_masks[i], av_masks[j]))
dev_warn(indio_dev->dev.parent,
- "available_scan_mask %d subset of %d. Never used\n",
- j, i);
- }
- }
+ "Mask %d (0x%lx) is a subset of mask %d (0x%lx) and will be ignored\n",
+ i, av_masks[i], j, av_masks[j]);
}
/**
--
2.34.1
The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable(a)vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 90abee6d7895d5eef18c91d870d8168be4e76e9d
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025042150-hardiness-hunting-0780@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 90abee6d7895d5eef18c91d870d8168be4e76e9d Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes(a)cmpxchg.org>
Date: Mon, 7 Apr 2025 14:01:53 -0400
Subject: [PATCH] mm: page_alloc: speed up fallbacks in rmqueue_bulk()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
The test robot identified c2f6ea38fc1b ("mm: page_alloc: don't steal
single pages from biggest buddy") as the root cause of a 56.4% regression
in vm-scalability::lru-file-mmap-read.
Carlos reports an earlier patch, c0cd6f557b90 ("mm: page_alloc: fix
freelist movement during block conversion"), as the root cause for a
regression in worst-case zone->lock+irqoff hold times.
Both of these patches modify the page allocator's fallback path to be less
greedy in an effort to stave off fragmentation. The flip side of this is
that fallbacks are also less productive each time around, which means the
fallback search can run much more frequently.
Carlos' traces point to rmqueue_bulk() specifically, which tries to refill
the percpu cache by allocating a large batch of pages in a loop. It
highlights how once the native freelists are exhausted, the fallback code
first scans orders top-down for whole blocks to claim, then falls back to
a bottom-up search for the smallest buddy to steal. For the next batch
page, it goes through the same thing again.
This can be made more efficient. Since rmqueue_bulk() holds the
zone->lock over the entire batch, the freelists are not subject to outside
changes; when the search for a block to claim has already failed, there is
no point in trying again for the next page.
Modify __rmqueue() to remember the last successful fallback mode, and
restart directly from there on the next rmqueue_bulk() iteration.
Oliver confirms that this improves beyond the regression that the test
robot reported against c2f6ea38fc1b:
commit:
f3b92176f4 ("tools/selftests: add guard region test for /proc/$pid/pagemap")
c2f6ea38fc ("mm: page_alloc: don't steal single pages from biggest buddy")
acc4d5ff0b ("Merge tag 'net-6.15-rc0' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net")
2c847f27c3 ("mm: page_alloc: speed up fallbacks in rmqueue_bulk()") <--- your patch
f3b92176f4f7100f c2f6ea38fc1b640aa7a2e155cc1 acc4d5ff0b61eb1715c498b6536 2c847f27c37da65a93d23c237c5
---------------- --------------------------- --------------------------- ---------------------------
%stddev %change %stddev %change %stddev %change %stddev
\ | \ | \ | \
25525364 ± 3% -56.4% 11135467 -57.8% 10779336 +31.6% 33581409 vm-scalability.throughput
Carlos confirms that worst-case times are almost fully recovered
compared to before the earlier culprit patch:
2dd482ba627d (before freelist hygiene): 1ms
c0cd6f557b90 (after freelist hygiene): 90ms
next-20250319 (steal smallest buddy): 280ms
this patch : 8ms
[jackmanb(a)google.com: comment updates]
Link: https://lkml.kernel.org/r/D92AC0P9594X.3BML64MUKTF8Z@google.com
[hannes(a)cmpxchg.org: reset rmqueue_mode in rmqueue_buddy() error loop, per Yunsheng Lin]
Link: https://lkml.kernel.org/r/20250409140023.GA2313@cmpxchg.org
Link: https://lkml.kernel.org/r/20250407180154.63348-1-hannes@cmpxchg.org
Fixes: c0cd6f557b90 ("mm: page_alloc: fix freelist movement during block conversion")
Fixes: c2f6ea38fc1b ("mm: page_alloc: don't steal single pages from biggest buddy")
Signed-off-by: Johannes Weiner <hannes(a)cmpxchg.org>
Signed-off-by: Brendan Jackman <jackmanb(a)google.com>
Reported-by: kernel test robot <oliver.sang(a)intel.com>
Reported-by: Carlos Song <carlos.song(a)nxp.com>
Tested-by: Carlos Song <carlos.song(a)nxp.com>
Tested-by: kernel test robot <oliver.sang(a)intel.com>
Closes: https://lore.kernel.org/oe-lkp/202503271547.fc08b188-lkp@intel.com
Reviewed-by: Brendan Jackman <jackmanb(a)google.com>
Tested-by: Shivank Garg <shivankg(a)amd.com>
Acked-by: Zi Yan <ziy(a)nvidia.com>
Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz>
Cc: <stable(a)vger.kernel.org> [6.10+]
Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org>
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9a219fe8e130..1715e34b91af 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2183,23 +2183,15 @@ try_to_claim_block(struct zone *zone, struct page *page,
}
/*
- * Try finding a free buddy page on the fallback list.
- *
- * This will attempt to claim a whole pageblock for the requested type
- * to ensure grouping of such requests in the future.
- *
- * If a whole block cannot be claimed, steal an individual page, regressing to
- * __rmqueue_smallest() logic to at least break up as little contiguity as
- * possible.
+ * Try to allocate from some fallback migratetype by claiming the entire block,
+ * i.e. converting it to the allocation's start migratetype.
*
* The use of signed ints for order and current_order is a deliberate
* deviation from the rest of this file, to make the for loop
* condition simpler.
- *
- * Return the stolen page, or NULL if none can be found.
*/
static __always_inline struct page *
-__rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
+__rmqueue_claim(struct zone *zone, int order, int start_migratetype,
unsigned int alloc_flags)
{
struct free_area *area;
@@ -2237,14 +2229,29 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
page = try_to_claim_block(zone, page, current_order, order,
start_migratetype, fallback_mt,
alloc_flags);
- if (page)
- goto got_one;
+ if (page) {
+ trace_mm_page_alloc_extfrag(page, order, current_order,
+ start_migratetype, fallback_mt);
+ return page;
+ }
}
- if (alloc_flags & ALLOC_NOFRAGMENT)
- return NULL;
+ return NULL;
+}
+
+/*
+ * Try to steal a single page from some fallback migratetype. Leave the rest of
+ * the block as its current migratetype, potentially causing fragmentation.
+ */
+static __always_inline struct page *
+__rmqueue_steal(struct zone *zone, int order, int start_migratetype)
+{
+ struct free_area *area;
+ int current_order;
+ struct page *page;
+ int fallback_mt;
+ bool claim_block;
- /* No luck claiming pageblock. Find the smallest fallback page */
for (current_order = order; current_order < NR_PAGE_ORDERS; current_order++) {
area = &(zone->free_area[current_order]);
fallback_mt = find_suitable_fallback(area, current_order,
@@ -2254,25 +2261,28 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
page = get_page_from_free_area(area, fallback_mt);
page_del_and_expand(zone, page, order, current_order, fallback_mt);
- goto got_one;
+ trace_mm_page_alloc_extfrag(page, order, current_order,
+ start_migratetype, fallback_mt);
+ return page;
}
return NULL;
-
-got_one:
- trace_mm_page_alloc_extfrag(page, order, current_order,
- start_migratetype, fallback_mt);
-
- return page;
}
+enum rmqueue_mode {
+ RMQUEUE_NORMAL,
+ RMQUEUE_CMA,
+ RMQUEUE_CLAIM,
+ RMQUEUE_STEAL,
+};
+
/*
* Do the hard work of removing an element from the buddy allocator.
* Call me with the zone->lock already held.
*/
static __always_inline struct page *
__rmqueue(struct zone *zone, unsigned int order, int migratetype,
- unsigned int alloc_flags)
+ unsigned int alloc_flags, enum rmqueue_mode *mode)
{
struct page *page;
@@ -2291,16 +2301,48 @@ __rmqueue(struct zone *zone, unsigned int order, int migratetype,
}
}
- page = __rmqueue_smallest(zone, order, migratetype);
- if (unlikely(!page)) {
- if (alloc_flags & ALLOC_CMA)
+ /*
+ * First try the freelists of the requested migratetype, then try
+ * fallbacks modes with increasing levels of fragmentation risk.
+ *
+ * The fallback logic is expensive and rmqueue_bulk() calls in
+ * a loop with the zone->lock held, meaning the freelists are
+ * not subject to any outside changes. Remember in *mode where
+ * we found pay dirt, to save us the search on the next call.
+ */
+ switch (*mode) {
+ case RMQUEUE_NORMAL:
+ page = __rmqueue_smallest(zone, order, migratetype);
+ if (page)
+ return page;
+ fallthrough;
+ case RMQUEUE_CMA:
+ if (alloc_flags & ALLOC_CMA) {
page = __rmqueue_cma_fallback(zone, order);
-
- if (!page)
- page = __rmqueue_fallback(zone, order, migratetype,
- alloc_flags);
+ if (page) {
+ *mode = RMQUEUE_CMA;
+ return page;
+ }
+ }
+ fallthrough;
+ case RMQUEUE_CLAIM:
+ page = __rmqueue_claim(zone, order, migratetype, alloc_flags);
+ if (page) {
+ /* Replenished preferred freelist, back to normal mode. */
+ *mode = RMQUEUE_NORMAL;
+ return page;
+ }
+ fallthrough;
+ case RMQUEUE_STEAL:
+ if (!(alloc_flags & ALLOC_NOFRAGMENT)) {
+ page = __rmqueue_steal(zone, order, migratetype);
+ if (page) {
+ *mode = RMQUEUE_STEAL;
+ return page;
+ }
+ }
}
- return page;
+ return NULL;
}
/*
@@ -2312,6 +2354,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
unsigned long count, struct list_head *list,
int migratetype, unsigned int alloc_flags)
{
+ enum rmqueue_mode rmqm = RMQUEUE_NORMAL;
unsigned long flags;
int i;
@@ -2323,7 +2366,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
}
for (i = 0; i < count; ++i) {
struct page *page = __rmqueue(zone, order, migratetype,
- alloc_flags);
+ alloc_flags, &rmqm);
if (unlikely(page == NULL))
break;
@@ -2948,7 +2991,9 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone,
if (alloc_flags & ALLOC_HIGHATOMIC)
page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
if (!page) {
- page = __rmqueue(zone, order, migratetype, alloc_flags);
+ enum rmqueue_mode rmqm = RMQUEUE_NORMAL;
+
+ page = __rmqueue(zone, order, migratetype, alloc_flags, &rmqm);
/*
* If the allocation fails, allow OOM handling and