Linux Kernel 2.6.24 Released

LinuxFan writes "Linus Torvalds has released the 2.6.24 Linux Kernel, noting that he and most of the other key Linux developers will be flying to a conference in Australia for the next week. As the whole team will be down under while the kernel is being tested by the masses, Linus added, "Let's hope it's a good one". What's new in the latest release includes an optimized CFQ scheduler, numerous new wireless drivers, tickless kernel support for the x86-64 and PPC architectures, and much more. Time to download and start compiling."

Comments

Anti-Fragmentation?

[kripkenstein]

The updates most interesting to me are the anti-fragmentation patches,

Tests show that about 60-70% of physical memory can be allocated on a desktop after a few days uptime. In benchmarks and stress tests, it has been found that 80% of memory is available as contiguous blocks at the end of the test. To compare, a standard kernel was getting ~1% of memory as large pages on a desktop and about 8-12% of memory as large pages at the end of stress tests.

Perhaps someone can clarify exactly what this means? Reading the beginning, it talked about 4K pages, device drivers, and such, so I assumed it would just be relevant to the internal workings of the kernel. However, the quote I pasted above seems to indicate it might impact desktop performance as well.

I commonly see on my desktop, after several days uptime, that quite a lot of memory is being used (and I know how to ignore cache/buffers, as well as swapcache - that isn't the issue). Logging out and logging back in returns memory to reasonable levels (and the system becomes more responsive, but then I guess if I bought more memory I could accomplish that as well). Now, I've generally read that the problem was indeed memory fragmentation, e.g. here, but this would be internal fragmentation inside an app, and thus not relevant to the kernel, I believe? If someone can explain this issue I'd be grateful.