For those who want to try:
- Apply the latest patches from developerworks including dcss block device
- Apply the patches from linuxvm
- make sure to select xip2 filesystem in the filesystems menu, and dcss
block device support in block devices
- compile and install
- create a dcss with ext2 filesystem on it, and put executable files and
libraries onto the filesystem
- save the dcss segment using the block device
- reboot and issue a command like
mount -t xip2 -o ro,memarea=MYDCSS none /mnt
to mount the new filesystem and gain memory resources 8-))
with kind regards
Carsten Otte
--
I saw screens of green, red messages too, then came blue, shubidu
And i think to myself, what a wonderful world
Mark Post <[EMAIL PROTECTED]>
Sent by: Linux on 390 Port <[EMAIL PROTECTED]>
25/02/2004 06:51 AM
Please respond to Linux on 390 Port
To: [EMAIL PROTECTED]
cc:
Subject: New xip2fs patches on the web site
I received two patches from SUSE against the 2.4.21 Linux kernel that
implement xip2fs, or Execute In Place ext2 file system. The commentary I
received was this:
"Xip2fs is a file system driver that allows you to mount an
ext2-compatible
file system from a DCSS (VM Discontiguous Shared Segment). The benefit of
using xip2fs instead of mounting the file system as ext2 using the DCSS
block device driver is that xip2fs provides execute-in-place capability.
"This means that memory-mapping a file residing on xip2fs will simply
result
in the user process' page table entries pointing directly to the DCSS
pages,
as opposed to reading file pages into the page cache (as a typical ext2
mounted file system would do).
"Since all executables and shared libraries are memory-mapped in order to
execute, running those from an xip2 mounted file system will mean that all
processes across all VM guests in the system that use these files will
share
the same physical pages of memory to hold the executable code, potentially
resulting in significant overall memory savings."
This looks like a nice way to reduce the storage footprint for Linux/390
guests that are using a shared read-only file system in a DCSS.
My understanding is that documentation for this new driver will be
arriving
in the next week or so. When I hear anything definite, I'll send another
note to the list.
The patches are at http://linuxvm.org/Patches, as usual, but there appears
to be a problem with the web server when trying to retrieve patch #1. So,
instead of using
file:///d:/webpages/linuxvm.org/Patches/S390/xip2fs_part1.diff.gz as the
URL, try file:///d:/webpages/linuxvm.org/Patches/S390/xip2fs1.gz and see
if
that works better.
Mark Post
