* Christoph Hellwig <[EMAIL PROTECTED]> wrote: > On Sun, Jan 28, 2007 at 03:11:34PM +0100, Peter Zijlstra wrote: > > Eradicate global locks. > > > > - kmap_lock is removed by extensive use of atomic_t, a new flush > > scheme and modifying set_page_address to only allow NULL<->virt > > transitions. > > What's the point for this? [...]
scalability. I did lock profiling on the -rt kernel, which exposes such things nicely. Half of the lock contention events during kernel compile were due to kmap(). (The system had 2 GB of RAM, so 40% lowmem, 60% highmem.) > [...] In doubt we just need to convert that caller to kmap_atomic. the pagecache ones cannot be converted to kmap_atomic, because we can block while holding them. Plus kmap_atomic is quite a bit slower than this scalable version of kmap(). Ingo ps. please fix your mailer to not emit Mail-Followup-To headers. In Mutt you can do this via "set followup_to=no" in your .muttrc. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/