LKML News v5.15-rc3

[RFC PATCH] Introducing lockless cache built on top of slab allocator (Hyeonggon Yoo)

https://lkml.kernel.org/r/20210919164239.49905-1-42.hyeyoo@gmail.com

The block layer now has a lockless cache, which increased its IOPS. This RFC generalizes it so that it can be used in some other area, such as NAPI.

[PATCH v5 0/3] virtio-mem: disallow mapping virtio-mem memory via /dev/mem (David Hildenbrand)

https://lkml.kernel.org/r/20210920142856.17758-1-david@redhat.com

This patchset makes a basic infrastructure to exclude some physical memory regions that marked as IORESOURCE_SYSTEM_RAM from /dev/mem access, even though they are not marked as IORESOURCE_BUSY.

BoF at LPC: Documenting the Heterogeneous Memory Model Architecture (Felix Kuehling)

https://lkml.kernel.org/r/23aeacb6-0cd9-d10f-76bc-3c9d33905daa@amd.com

A BoF session for documentation of heterogeneous memory model, which let memory of GPU-like accelerators aggregated with system RAM, is proposed.

mmotm 2021-09-21-16-54 uploaded (Andrew Morton)

https://lkml.kernel.org/r/20210921235437.zcAiZPmxd%akpm@linux-foundation.org

MMOTM updated. 0 patch dropped, 30 patches added, and 13 patches modified.

Struct page proposal (Ken Overstreet)

https://lkml.kernel.org/r/YUvWm6G16+ib+Wnb@moria.home.lan

In this mail, Ken describes one common point from Matthew and Johannes in the Folios discussion, and proposes new struct page. It contains only two pointers, so the memory overhead for struct page objects becomes only 0.4%.

incoming (Andrew Morton)

https://lkml.kernel.org/r/20210924154257.1dbf6699ab8d88c0460f924f@linux-foundation.org

Pull request from Andrew Morton for various fixes.

[PATCH 0/2] mm/mprotect: avoid unnecessary TLB flushes (Nadav Amit)

https://lkml.kernel.org/r/20210925205423.168858-1-namit@vmware.com

Memory-unprotect using usefaultfd (i.e., userfaultfd IOCTL) triggers a TLB flush even though no architectural data but only a software flag is updated. This patchset tries to solve the issue by not tailoring the specific scenario but consolidating the interfaces for TLB batching. This patchset is based on an old RFC.

Linux 5.15-rc3 (Linus Torvalds)

https://lkml.kernel.org/r/CAHk-=wgoE8XBPVA6Mu4CygxX9TE0FgWaAsVUJOe8KQH-CzEcAA@mail.gmail.com

Partly because of the Werror change, 5.15 rc2 was not so calm. Now seems the things wound down and it became normal, Torvalds says.

Below is the diffstat of the releases in the last two years.

Note that the y-axis is in logarithm. I draw it using https://github.com/sjp38/relstat and https://github.com/sjp38/lazybox using below command:

$ relstat.py --since 2019-09-20 | ~/lazybox/gnuplot/plot.py \
    --data_fmt table --type labeled-lines --xtics_rotate -90 \
    --font "Times New Roman, 5pt" --ylog --pointsize 0.3

And, below is the diffstat of the -rc2 releases in the last two years.