Re: [PATCH] Use of getblk differs between locations

From: Mikulas Patocka
Date: Wed Oct 12 2005 - 15:12:40 EST

Is memory management ready for this? Can't deadlock like this happen?
- displaying dialog window needs memory, so it waits until memory will
be available
- system decides to write some write-back cached data in order to free
- the write of these data waits until the dialog window is displayed,
user inserts the device and clicks 'OK'

No, it's not, and deadlock is definitely possible. However, if we're at
the point where memory is tight enough that it's an issue, the timer can
expire and all the pending i/o is dropped just as it would be without
the multipath code enabled.

I'm not saying it's a solution ready for production, just a good
starting point.

But discarding data sometimes on USB unplug is even worse than discarding data always --- users will by experimenting learn that linux doesn't discard write-cached data and reminds them to replug the device --- and one day, randomly, they lose their data because of some memory management condition...

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