On Sun, Aug 12, 2007 at 11:44:00PM -0700, Daniel Phillips (phillips@xxxxxxxxx) wrote: > On Sunday 12 August 2007 22:36, I wrote: > > Note! There are two more issues I forgot to mention earlier. > > Oops, and there is also: > > 3) The bio throttle, which is supposed to prevent deadlock, can itself > deadlock. Let me see if I can remember how it goes. > > * generic_make_request puts a bio in flight > * the bio gets past the throttle and initiates network IO > * net calls sk_alloc->alloc_pages->shrink_caches > * shrink_caches submits a bio recursively to our block device > * this bio blocks on the throttle > * net may never get the memory it needs, and we are wedged If system is in such condition, it is already broken - throttle limit must be lowered (next time) not to allow such situation. -- Evgeniy Polyakov - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
