[lkml]   [2004]   [Mar]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: 2.4.23aa2 (bugfixes and important VM improvements for the high end)
Andrew Morton wrote:
> We believe that this could cause misbehaviour of such things as the
> boehm garbage collector. This patch provides the mprotect() atomicity by
> performing all userspace copies under page_table_lock.

Can you use a read-write lock, so that userspace copies only need to
take the lock for reading? That doesn't eliminate cacheline bouncing
but does eliminate the serialisation.

Or did you do that already, and found performance is still very low?

> It is a judgement call. Personally, I wouldn't ship a production kernel
> with this patch. People need to be aware of the tradeoff and to think and
> test very carefully.

If this isn't fixed, _please_ provide a way for a garbage collector to
query the kernel as to whether this race condition is present.

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

 \ /
  Last update: 2005-03-22 14:01    [W:0.078 / U:5.840 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site