Raise CONFIG_NR_CPUS

Bug #1967889 reported by Heinrich Schuchardt
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux-riscv (Ubuntu)
Fix Released
Undecided
Emil Renner Berthing

Bug Description

[Impact]

 * Currently our riscv64 kernels don't support more than 8 CPUs.

 * The QEMU 7.0 virt machine supports up to 512 virtual CPUs.

 * Raising CONFIG_NR_CPUS to the maximum of 32 allows us to use
   more of them.

[Test Plan]

 * Run riscv64 Ubuntu in a QEMU virt instance with more than 8
   virtual CPUs and see that only 8 of them are used.

 * After raising CONFIG_NR_CPUS up to 32 of them should be used.

[Where problems could occur]

 * This will allocate slightly more RAM which might hurt very small
   machines.

[Other Info]

 * Original bug description:

The QEMU 7.0 virt machine offers up to 32 virtual harts. This matches the number of hardware threads on a typical desktop CPU (AMD Ryzen 5950X). Our Linux kernel should support this number of harts.

Best regards

Heinrich

CVE References

Revision history for this message
Heinrich Schuchardt (xypron) wrote :

The following patch sets reasonable values for CONFIG_NR_CPUS on RISC-V:

[PATCH v3] RISC-V: Increase range and default value of NR_CPUS
https://<email address hidden>/

Changed in linux-riscv (Ubuntu):
assignee: nobody → Emil Renner Berthing (esmil)
description: updated
description: updated
description: updated
description: updated
description: updated
Revision history for this message
Launchpad Janitor (janitor) wrote :
Download full text (160.9 KiB)

This bug was fixed in the package linux-riscv - 5.19.0-1003.3

---------------
linux-riscv (5.19.0-1003.3) kinetic; urgency=medium

  * kinetic/linux-riscv: 5.19.0-1003.3 -proposed tracker (LP: #1992335)

  * Packaging resync (LP: #1786013)
    - debian/dkms-versions -- update from kernel-versions (main/master)

  * Disable sv57 as the userspace is not ready (LP: #1991790)
    - SAUCE: riscv: mm: Force disable sv57

  * rcu_sched detected stalls on CPUs/tasks (LP: #1967130)
    - [Packaging] Keep VMAP_STACK off

  * earlyconsole prints question marks on 5.19.0-1002-generic (LP: #1988984)
    - [Config] Set CONFIG_PWM_SIFIVE=m for

  * Miscellaneous Ubuntu changes
    - [Packaging] suffixless backport kernel, handle it as an exception
    - [Packaging] Add helper scripts
    - [Packaging] Use all annotations from parent
    - [Packaging] Review master changes
    - [Packaging] Adjust ABI after config changes.

  [ Ubuntu: 5.19.0-19.19 ]

  * kinetic/linux: 5.19.0-19.19 -proposed tracker (LP: #1990960)
  * kinetic: apply new apparmor and LSM stacking patch set (LP: #1989983)
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Specify which LSM to display
      (using struct cred as input)"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: apparmor: Fix build error, make sk
      parameter const"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Use lsmblob in
      smk_netlbl_mls()"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: change ima_read_file() to use
      lsmblob"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: apparmor: rename kzfree() to
      kfree_sensitive()"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: Audit: Fix for missing NULL check"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: AppArmor: Remove the exclusive
      flag"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Add /proc attr entry for full
      LSM context"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: Audit: Add a new record for multiple
      object LSM attributes"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: Audit: Fix incorrect static inline
      function declration."""
    - Revert "Revert "Revert "UBUNTU: SAUCE: Audit: Add new record for multiple
      process LSM attributes"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: NET: Store LSM netlabel data in a
      lsmblob"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: security_secid_to_secctx in
      netlink netfilter"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Use lsmcontext in
      security_inode_getsecctx"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Use lsmcontext in
      security_secid_to_secctx"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Ensure the correct LSM context
      releaser"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Specify which LSM to display"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: IMA: Change internal interfaces to
      use lsmblobs"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Use lsmblob in
      security_cred_getsecid"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Use lsmblob in
      security_inode_getsecid"""
    - Revert "Revert "Revert "UBUNTU: SAUCE: LSM: Use lsmblob in
      security_task_getsecid"""
    - Rever...

Changed in linux-riscv (Ubuntu):
status: New → Fix Released
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