Linux

5184 readers

119 users here now

A community for everything relating to the linux operating system

Also check out !linux_memes@programming.dev

Original icon base courtesy of lewing@isc.tamu.edu and The GIMP

founded 1 year ago

MODERATORS

Ategon@programming.dev

anzo@programming.dev

dwraf_of_ignorance@programming.dev

Linux 6.11 To Offer More Fine-Tuned Control Over Swappiness (www.phoronix.com)

submitted 4 months ago by lemmee_in@lemm.ee to c/linux@programming.dev

15 comments fedilink hide all child comments

As part of the memory management changes expected to be merged for the upcoming Linux 6.11 cycle is allowing more fine-tuned control over the swappiness setting used to determine how aggressively pages are swapped out of physical system memory and into the on-disk swap space.

With the new code from Meta, a swappiness argument is supported for memory.reclaim. This effectively allows more finer-grained control over the swapiness behavior without overriding the global swappiness setting.

you are viewing a single comment's thread
view the rest of the comments

[–] SpaceCadet@feddit.nl 2 points 4 months ago

If he’s processing LLMs or really any non-trivial DB (read: any business DB)

Actually... as a former DBA on large databases, you typically want to minimize swapping on a dedicated database system. Most database engines do a much better job at keeping useful data in memory than the Linux kernel's file caching, which is agnostic about what your files contain. There are some exceptions, like elasticsearch which almost entirely relies on the Linux filesystem cache for buffering I/O.

Anyway, database engines have query optimizers to determine the optimal path to resolve a query, but they rely on it that the buffers that they consider to be "in memory" are actually residing in physical memory, and not sitting in a swapfile somewhere.

So typically, on a large database system the vendor recommendation will be to set vm.swappiness=0 to minimize memory pressure from filesystem caching, and to set the database buffers as high as the amount of memory you have in your system minus a small amount for the operating system.