sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling buggrafted

alb_break_llc() decides whether to break LLC preference during active
load balance. It does so by testing that every runnable fair task on the
source rq prefers its LLC:

	env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable

But the two counters cover different sets. nr_pref_llc_running is updated
in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued,
so it follows queued tasks. h_nr_runnable is updated in set_delayed()/
clear_delayed() and drops delay-dequeued tasks.

So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted
in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks,
alb_break_llc() returns false, and active balance is free to pull a task
off its preferred LLC. Active balance only moves runnable tasks, and this
is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB
skips the per-task test in can_migrate_task(). The runnable set is the one
we want.

Fix it on the counter side. A task should be counted in
nr_pref_llc_running exactly while it is both queued on its preferred LLC
(pref_llc_queued) and runnable (!sched_delayed). Define that membership
once in task_pref_llc_runnable(), and adjust the counter only through
pref_llc_running_inc()/pref_llc_running_dec() from the four sites that
change either input: account_llc_enqueue(), account_llc_dequeue(),
set_delayed() and clear_delayed(). Gating every update on the same
predicate keeps the delay, wake and dequeue paths from double-counting
or underflowing; see the comments at those sites for the ordering.

nr_llc_running and sd->llc_counts are not touched and stay on queued
semantics.

Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC")
Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/
Reported-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kayra Cizmeci <kayracizmeci@gmail.com>
Cc: <stable@kernel.org> # v7.2.x
Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com

1 files changed, 288 insertions, 0 deletions

diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetable-offsets.c
new file mode 100644
index 000000000..b4178c42d
--- /dev/null
+++ b/scripts/mod/devicetable-offsets.c
@@ -0,0 +1,288 @@
+// SPDX-License-Identifier: GPL-2.0
+#define COMPILE_OFFSETS
+#include <linux/kbuild.h>
+#include <linux/mod_devicetable.h>
+
+#define DEVID(devid) DEFINE(SIZE_##devid, sizeof(struct devid))
+#define DEVID_FIELD(devid, field) \
+	DEFINE(OFF_##devid##_##field, offsetof(struct devid, field))
+
+int main(void)
+{
+	DEVID(usb_device_id);
+	DEVID_FIELD(usb_device_id, match_flags);
+	DEVID_FIELD(usb_device_id, idVendor);
+	DEVID_FIELD(usb_device_id, idProduct);
+	DEVID_FIELD(usb_device_id, bcdDevice_lo);
+	DEVID_FIELD(usb_device_id, bcdDevice_hi);
+	DEVID_FIELD(usb_device_id, bDeviceClass);
+	DEVID_FIELD(usb_device_id, bDeviceSubClass);
+	DEVID_FIELD(usb_device_id, bDeviceProtocol);
+	DEVID_FIELD(usb_device_id, bInterfaceClass);
+	DEVID_FIELD(usb_device_id, bInterfaceSubClass);
+	DEVID_FIELD(usb_device_id, bInterfaceProtocol);
+	DEVID_FIELD(usb_device_id, bInterfaceNumber);
+
+	DEVID(hid_device_id);
+	DEVID_FIELD(hid_device_id, bus);
+	DEVID_FIELD(hid_device_id, group);
+	DEVID_FIELD(hid_device_id, vendor);
+	DEVID_FIELD(hid_device_id, product);
+
+	DEVID(ieee1394_device_id);
+	DEVID_FIELD(ieee1394_device_id, match_flags);
+	DEVID_FIELD(ieee1394_device_id, vendor_id);
+	DEVID_FIELD(ieee1394_device_id, model_id);
+	DEVID_FIELD(ieee1394_device_id, specifier_id);
+	DEVID_FIELD(ieee1394_device_id, version);
+
+	DEVID(pci_device_id);
+	DEVID_FIELD(pci_device_id, vendor);
+	DEVID_FIELD(pci_device_id, device);
+	DEVID_FIELD(pci_device_id, subvendor);
+	DEVID_FIELD(pci_device_id, subdevice);
+	DEVID_FIELD(pci_device_id, class);
+	DEVID_FIELD(pci_device_id, class_mask);
+	DEVID_FIELD(pci_device_id, override_only);
+
+	DEVID(ccw_device_id);
+	DEVID_FIELD(ccw_device_id, match_flags);
+	DEVID_FIELD(ccw_device_id, cu_type);
+	DEVID_FIELD(ccw_device_id, cu_model);
+	DEVID_FIELD(ccw_device_id, dev_type);
+	DEVID_FIELD(ccw_device_id, dev_model);
+
+	DEVID(ap_device_id);
+	DEVID_FIELD(ap_device_id, dev_type);
+
+	DEVID(css_device_id);
+	DEVID_FIELD(css_device_id, type);
+
+	DEVID(serio_device_id);
+	DEVID_FIELD(serio_device_id, type);
+	DEVID_FIELD(serio_device_id, proto);
+	DEVID_FIELD(serio_device_id, id);
+	DEVID_FIELD(serio_device_id, extra);
+
+	DEVID(acpi_device_id);
+	DEVID_FIELD(acpi_device_id, id);
+	DEVID_FIELD(acpi_device_id, cls);
+	DEVID_FIELD(acpi_device_id, cls_msk);
+
+	DEVID(pnp_device_id);
+	DEVID_FIELD(pnp_device_id, id);
+
+	DEVID(pnp_card_device_id);
+	DEVID_FIELD(pnp_card_device_id, devs);
+
+	DEVID(pcmcia_device_id);
+	DEVID_FIELD(pcmcia_device_id, match_flags);
+	DEVID_FIELD(pcmcia_device_id, manf_id);
+	DEVID_FIELD(pcmcia_device_id, card_id);
+	DEVID_FIELD(pcmcia_device_id, func_id);
+	DEVID_FIELD(pcmcia_device_id, function);
+	DEVID_FIELD(pcmcia_device_id, device_no);
+	DEVID_FIELD(pcmcia_device_id, prod_id_hash);
+
+	DEVID(of_device_id);
+	DEVID_FIELD(of_device_id, name);
+	DEVID_FIELD(of_device_id, type);
+	DEVID_FIELD(of_device_id, compatible);
+
+	DEVID(vio_device_id);
+	DEVID_FIELD(vio_device_id, type);
+	DEVID_FIELD(vio_device_id, compat);
+
+	DEVID(input_device_id);
+	DEVID_FIELD(input_device_id, flags);
+	DEVID_FIELD(input_device_id, bustype);
+	DEVID_FIELD(input_device_id, vendor);
+	DEVID_FIELD(input_device_id, product);
+	DEVID_FIELD(input_device_id, version);
+	DEVID_FIELD(input_device_id, evbit);
+	DEVID_FIELD(input_device_id, keybit);
+	DEVID_FIELD(input_device_id, relbit);
+	DEVID_FIELD(input_device_id, absbit);
+	DEVID_FIELD(input_device_id, mscbit);
+	DEVID_FIELD(input_device_id, ledbit);
+	DEVID_FIELD(input_device_id, sndbit);
+	DEVID_FIELD(input_device_id, ffbit);
+	DEVID_FIELD(input_device_id, swbit);
+
+	DEVID(eisa_device_id);
+	DEVID_FIELD(eisa_device_id, sig);
+
+	DEVID(parisc_device_id);
+	DEVID_FIELD(parisc_device_id, hw_type);
+	DEVID_FIELD(parisc_device_id, hversion);
+	DEVID_FIELD(parisc_device_id, hversion_rev);
+	DEVID_FIELD(parisc_device_id, sversion);
+
+	DEVID(sdio_device_id);
+	DEVID_FIELD(sdio_device_id, class);
+	DEVID_FIELD(sdio_device_id, vendor);
+	DEVID_FIELD(sdio_device_id, device);
+
+	DEVID(ssb_device_id);
+	DEVID_FIELD(ssb_device_id, vendor);
+	DEVID_FIELD(ssb_device_id, coreid);
+	DEVID_FIELD(ssb_device_id, revision);
+
+	DEVID(bcma_device_id);
+	DEVID_FIELD(bcma_device_id, manuf);
+	DEVID_FIELD(bcma_device_id, id);
+	DEVID_FIELD(bcma_device_id, rev);
+	DEVID_FIELD(bcma_device_id, class);
+
+	DEVID(virtio_device_id);
+	DEVID_FIELD(virtio_device_id, device);
+	DEVID_FIELD(virtio_device_id, vendor);
+
+	DEVID(hv_vmbus_device_id);
+	DEVID_FIELD(hv_vmbus_device_id, guid);
+
+	DEVID(rpmsg_device_id);
+	DEVID_FIELD(rpmsg_device_id, name);
+
+	DEVID(i2c_device_id);
+	DEVID_FIELD(i2c_device_id, name);
+
+	DEVID(i3c_device_id);
+	DEVID_FIELD(i3c_device_id, match_flags);
+	DEVID_FIELD(i3c_device_id, dcr);
+	DEVID_FIELD(i3c_device_id, manuf_id);
+	DEVID_FIELD(i3c_device_id, part_id);
+	DEVID_FIELD(i3c_device_id, extra_info);
+
+	DEVID(slim_device_id);
+	DEVID_FIELD(slim_device_id, manf_id);
+	DEVID_FIELD(slim_device_id, prod_code);
+
+	DEVID(spi_device_id);
+	DEVID_FIELD(spi_device_id, name);
+
+	DEVID(dmi_system_id);
+	DEVID_FIELD(dmi_system_id, matches);
+
+	DEVID(platform_device_id);
+	DEVID_FIELD(platform_device_id, name);
+
+	DEVID(mdio_device_id);
+	DEVID_FIELD(mdio_device_id, phy_id);
+	DEVID_FIELD(mdio_device_id, phy_id_mask);
+
+	DEVID(zorro_device_id);
+	DEVID_FIELD(zorro_device_id, id);
+
+	DEVID(isapnp_device_id);
+	DEVID_FIELD(isapnp_device_id, vendor);
+	DEVID_FIELD(isapnp_device_id, function);
+
+	DEVID(ipack_device_id);
+	DEVID_FIELD(ipack_device_id, format);
+	DEVID_FIELD(ipack_device_id, vendor);
+	DEVID_FIELD(ipack_device_id, device);
+
+	DEVID(amba_id);
+	DEVID_FIELD(amba_id, id);
+	DEVID_FIELD(amba_id, mask);
+
+	DEVID(mips_cdmm_device_id);
+	DEVID_FIELD(mips_cdmm_device_id, type);
+
+	DEVID(x86_cpu_id);
+	DEVID_FIELD(x86_cpu_id, feature);
+	DEVID_FIELD(x86_cpu_id, family);
+	DEVID_FIELD(x86_cpu_id, model);
+	DEVID_FIELD(x86_cpu_id, vendor);
+
+	DEVID(cpu_feature);
+	DEVID_FIELD(cpu_feature, feature);
+
+	DEVID(mcb_device_id);
+	DEVID_FIELD(mcb_device_id, device);
+
+	DEVID(mei_cl_device_id);
+	DEVID_FIELD(mei_cl_device_id, name);
+	DEVID_FIELD(mei_cl_device_id, uuid);
+	DEVID_FIELD(mei_cl_device_id, version);
+
+	DEVID(rio_device_id);
+	DEVID_FIELD(rio_device_id, did);
+	DEVID_FIELD(rio_device_id, vid);
+	DEVID_FIELD(rio_device_id, asm_did);
+	DEVID_FIELD(rio_device_id, asm_vid);
+
+	DEVID(ulpi_device_id);
+	DEVID_FIELD(ulpi_device_id, vendor);
+	DEVID_FIELD(ulpi_device_id, product);
+
+	DEVID(hda_device_id);
+	DEVID_FIELD(hda_device_id, vendor_id);
+	DEVID_FIELD(hda_device_id, rev_id);
+	DEVID_FIELD(hda_device_id, api_version);
+
+	DEVID(sdw_device_id);
+	DEVID_FIELD(sdw_device_id, mfg_id);
+	DEVID_FIELD(sdw_device_id, part_id);
+	DEVID_FIELD(sdw_device_id, sdw_version);
+	DEVID_FIELD(sdw_device_id, class_id);
+
+	DEVID(fsl_mc_device_id);
+	DEVID_FIELD(fsl_mc_device_id, vendor);
+	DEVID_FIELD(fsl_mc_device_id, obj_type);
+
+	DEVID(tb_service_id);
+	DEVID_FIELD(tb_service_id, match_flags);
+	DEVID_FIELD(tb_service_id, protocol_key);
+	DEVID_FIELD(tb_service_id, protocol_id);
+	DEVID_FIELD(tb_service_id, protocol_version);
+	DEVID_FIELD(tb_service_id, protocol_revision);
+
+	DEVID(typec_device_id);
+	DEVID_FIELD(typec_device_id, svid);
+
+	DEVID(tee_client_device_id);
+	DEVID_FIELD(tee_client_device_id, uuid);
+
+	DEVID(wmi_device_id);
+	DEVID_FIELD(wmi_device_id, guid_string);
+
+	DEVID(mhi_device_id);
+	DEVID_FIELD(mhi_device_id, chan);
+
+	DEVID(auxiliary_device_id);
+	DEVID_FIELD(auxiliary_device_id, name);
+
+	DEVID(ssam_device_id);
+	DEVID_FIELD(ssam_device_id, match_flags);
+	DEVID_FIELD(ssam_device_id, domain);
+	DEVID_FIELD(ssam_device_id, category);
+	DEVID_FIELD(ssam_device_id, target);
+	DEVID_FIELD(ssam_device_id, instance);
+	DEVID_FIELD(ssam_device_id, function);
+
+	DEVID(dfl_device_id);
+	DEVID_FIELD(dfl_device_id, type);
+	DEVID_FIELD(dfl_device_id, feature_id);
+
+	DEVID(ishtp_device_id);
+	DEVID_FIELD(ishtp_device_id, guid);
+
+	DEVID(cdx_device_id);
+	DEVID_FIELD(cdx_device_id, vendor);
+	DEVID_FIELD(cdx_device_id, device);
+	DEVID_FIELD(cdx_device_id, subvendor);
+	DEVID_FIELD(cdx_device_id, subdevice);
+	DEVID_FIELD(cdx_device_id, class);
+	DEVID_FIELD(cdx_device_id, class_mask);
+	DEVID_FIELD(cdx_device_id, override_only);
+
+	DEVID(vchiq_device_id);
+	DEVID_FIELD(vchiq_device_id, name);
+
+	DEVID(coreboot_device_id);
+	DEVID_FIELD(coreboot_device_id, tag);
+
+	return 0;
+}