Re: [PATCH v3 11/13] x86/xen: use lazy_mmu_state when context-switching
From: David Hildenbrand <hidden>
Date: 2025-10-24 15:47:19
Also in:
linux-arm-kernel, linux-mm, lkml, sparclinux, xen-devel
On 24.10.25 17:38, John Paul Adrian Glaubitz wrote:
On Fri, 2025-10-24 at 16:13 +0100, David Woodhouse wrote:quoted
On Fri, 2025-10-24 at 16:51 +0200, David Hildenbrand wrote:quoted
On 24.10.25 16:47, David Woodhouse wrote:quoted
On Thu, 2025-10-23 at 22:06 +0200, David Hildenbrand wrote:quoted
On 15.10.25 10:27, Kevin Brodsky wrote:quoted
We currently set a TIF flag when scheduling out a task that is in lazy MMU mode, in order to restore it when the task is scheduled again. The generic lazy_mmu layer now tracks whether a task is in lazy MMU mode in task_struct::lazy_mmu_state. We can therefore check that state when switching to the new task, instead of using a separate TIF flag. Signed-off-by: Kevin Brodsky <redacted> ---Looks ok to me, but I hope we get some confirmation from x86 / xen folks.I know tglx has shouted at me in the past for precisely this reminder, but you know you can test Xen guests under QEMU/KVM now and don't need to actually run Xen? Has this been boot tested?And after that, boot-testing sparc as well? :DAlso not that hard in QEMU, I believe. Although I do have some SPARC boxes in the shed...Please have people test kernel changes on SPARC on real hardware. QEMU does not emulate sun4v, for example, and therefore testing in QEMU does not cover all of SPARC hardware. There are plenty of people on the debian-sparc, gentoo-sparc and sparclinux LKML mailing lists that can test kernel patches for SPARC. If SPARC-relevant changes need to be tested, please ask there and don't bury such things in a deeply nested thread in a discussion which doesn't even have SPARC in the mail subject.
Hi Adrian, out of curiosity, do people monitor sparclinux@ for changes to actively offer testing when required -- like would it be sufficient to CC relevant maintainers+list (like done here) and raise in the cover letter that some testing help would be appreciated? -- Cheers David / dhildenb