Muli Ben-Yehuda's journal

July 2, 2003

Mel Gorman’s VM book

Filed under: Uncategorized — Muli Ben-Yehuda @ 2:46 PM

Earlier this week, I got this nice email from Mel Gorman, author of the
excellent Linux Kernel VM documentation. Mel wrote:

“I’ve been offered a contract to write a book on the Linux VM with Prentice Hall based on the material I’ve made available to date at http://www.csn.ul.ie/~mel/projects/vm/

If you’re reading this, you are in the acknowledgments section for helping me out at some stage at the other getting the 2.4 docs together …”

The book is going to come out as part of Bruce Peren’s Open Series, but you should all go out and buy it, of course. I know I will. And after you buy it, make sure to highlight my name in the acknowledgments section 🙂

For those curious, here’s the email I sent Mel that will get me mentioned in the book:

First one:

 
Date: Sun, 12 Jan 2003 19:29:43 +0200
From: Muli Ben-Yehuda 
User-Agent: Mutt/1.4i
To: Mel Gorman 
Subject: typo in vmalloc document

Hi Mel,

In http://www.csn.ul.ie/~mel/projects/vm/docs/vmalloc.html, section
1.1, you wrote:
       if (vmalloc_area_pages(VMALLOC_VMADDR(addr), size, gfp_mask, prot)) {
                vfree(addr);
                return NULL;
        }

vmalloc_area_pages sets up the PGD, PMD and PTE entries to give out
the linear addresses needed. If it fails half way through, 0 is
returned so that vfree can be called to get rid of the PGD, PMD and
PTE entries that have been assigned.

END QUOTE

the '0 is returned' bit is wrong - it should be '-ERRNO is returned',
or at least, 'a non zero value is returned'.
--
Muli Ben-Yehuda

my opinions may seem crazy. But they all make sense. Insane sense, but
sense nontheless. -- Shlomi Fish on #offtopic.

And:

Date: Wed, 2 Apr 2003 14:30:55 +0300
From: Muli Ben-Yehuda 
User-Agent: Mutt/1.5.4i
To: Mel Gorman 
Subject: bug(?) in VM documentation

Apr 1st copy, page 39, section 4.4

"...
 mk_pte() takes a physical page...
 mk_pte_phys() treats the address as a physical page
 ..."

Looking at the code, I mk_pte appears to take a struct page, not a
physical page (which I parse as a physical page address).

Thanks,
Muli.
--
Muli Ben-Yehuda
http://www.mulix.org

Who woulda thunk? 🙂

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