Memory filesystems

From: Warren Young (
Date: Sun May 28 2000 - 12:24:07 EST

I've been following the discussion about memory filesystems via Kernel
Traffic, and I got the impression that they were considered just a side
project, not terribly useful in the main kernel. Memory filesystems are
mainly useful for things like /tmp. The logic goes, because Linux's
buffer cache is so aggressive, temporaries spend their entire lives in
memory anyway.

Well, something occurred to me just now: wouldn't journalling wreck this
pretty picture? With journalling, all disk writes have to go
immediately to the disk instead of waiting in memory until the kernel
gets bored and flushes buffers to disk.

I suppose you could write a JFS that still was lazy about flushing
buffers, but it then you only gain disk coherency from the JFS. Such a
JFS could obey the "-o sync" mount option and use lazy buffer flushing
only when the option isn't given.

Just some thoughts,

= Warren Young, maintainer of the Winsock Programmer's FAQ at:
= ICBM Address: 36.8274040 N, 108.0204086 W, alt. 1714m

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to Please read the FAQ at

This archive was generated by hypermail 2b29 : Wed May 31 2000 - 21:00:19 EST