Muli Ben-Yehuda's journal

June 26, 2003

The Days of Our Gentoo Soap Opera

Filed under: Uncategorized — Muli Ben-Yehuda @ 1:14 PM

(as seen on /.)

Some guy is forking gentoo Linux, as far as I can see, because he expected to make money out of his involvement and didn’t. His manifest, and drobbins’s rebuttal. I couldn’t care less[0] who’s right, but it’s certainly amusing to read.

[0] Uhm, maybe I could care a little – drobbins strikes me as an honest person, while that Zach person reminds me of Moshe Bar, full of his own perceived importance.

Linux VM extravaganza

Filed under: Uncategorized — Muli Ben-Yehuda @ 9:14 AM

Reading’s weekly kernel page (subscribers only for this week, sorry), I ran across a link to the Object Based Reversed Mapping patch, aka objrmap. To summarize, objrmap differs from Rik van Riel’s rmap by tracking pte entries by page->mappging->vma, instead of special pte_chains. That left me curious, as I know that wli’s tree includes Anonymous objrmap, aka anobjrmap, which extends the objrmap implementation for anonymous pages, which don’t have an associated mapping! how does it work, then? Some googling later, I found Hugh Dickins’s anobjrmap patches (scroll down to memory management). Putting it very roughly, anobjrmap tracks anonymous pages by a new struct, anonmm, which is attached to the mm, and serves as the page’s mapping.

While I’m in a kernel mood, two more things: Peter Braam, one of the intermezzo hackers, CC’d me on a mail to Chen Yang, asking him to integrate my intermezzo patch of last night and send it on to Linus. Neat! Also, I wonder if the folks at work or haifux would be interested in a series of lectures on the 2.5 VM. A prerequisite for such a lecture is writing at least one reasonably sized VM patch, though.

intermezzo stack lossage

Filed under: Uncategorized — Muli Ben-Yehuda @ 12:02 AM

intermezzo-stack-lossage-2.5.73.diff is tonight’s work. This patch reduces intermezzo’s stack usage in three functions. The kernel has limited stack space for functions, and functions which use 4kb and even 1kb of stack space are unacceptable. Against 2.5.73.

I don’t really expect this patch to get in, as the intermezzo people seem to be ignoring 2.5 for the time being. However, wli said he’s interested in it, as his tree uses 4kb stacks, and maybe someone else will find it interesting as well? other than the grunginess of the intermezzo code, it was fun to write. I should write more kernel code.

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