LKML News v5.9-rc2

PROBLEM: Long Workqueue delays. (Jim Baxter)

https://lkml.kernel.org/r/71aafe68-7fe0-6b77-ea8e-83edd3f16c8d@mentor.com

Jim Baxter encountered 6.5 seconds delay due to long workqueue delay. He want to ask if this is normal or real problem.

[RFC PATCH 0/8] memcg: Enable fine-grained per process memory control (Waiman Long)

https://lkml.kernel.org/r/20200817140831.30260-1-longman@redhat.com

The memory cgroup v2 start reclamation if the amount of the memory of the cgroup exceeds ‘memory.high’ and start OOM killing if if exceeds ‘memory.max’. Problem is, the OOM killer can kill any process. This patchset makes the target of the OOM killing can be selected by user.

[PATCH v5 0/2] Anonymous VMA naming patches (Sumit Semwal)

https://lkml.kernel.org/r/20200819141650.7462-1-sumit.semwal@linaro.org

This patchset was originally sent by Colin Cross a long time ago but Sumit Semwal reposting this as he realised that this patchset is needed for Android to boot.

[PATCH RFC] mm: increase page waitqueue hash size (Nicholas Piggin)

https://lkml.kernel.org/r/20200819125349.558249-1-npiggin@gmail.com

Nicholas found the page waitqueue hash is a bit small on his 16 socket 1536 threads POWER9 system. He increased the waitqueue hash size from 256 to 262144 and it made 182% performance improvement.

[PATCH 0/78] Transparent Huge Pages for XFS (Matthew Wilcox)

https://lkml.kernel.org/r/20200821224522.GX17456@casper.infradead.org

Matthew’s THP for file-backed pages now passes xfstests. For this, he made 78 patches. However, because no one really like to review 78 patches, he just want to let people know this and a portion of the patches is already formatted as 5 individual patchsets. He hopes some of the patchsets to be merged in v5.10.

Biggest change this patchset makes is variable-sized THPs. He made this change because filesystems would prefer a page size between PAGE_SIZE and PMD_SIZE. PMD_SIZE is the only one size for THP now.

Linux 5.9-rc2 (Linus Torvalds)

https://lkml.kernel.org/r/CAHk-=wiy7qFBRVibt+kHoceCwsiPeMRZXDajq1oCsk+AUOU4cg@mail.gmail.com

The rc2 for 5.9 came out. Nothing in particular. Many fixes in file systems because ext4 update came in late.

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 2018-08-24 | ~/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.