Messages in this thread | | | Date | Tue, 27 Sep 2011 18:20:20 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH v5 3.1.0-rc4-tip 18/26] uprobes: slot allocation. |
| |
* Peter Zijlstra <peterz@infradead.org> [2011-09-27 14:37:59]:
> On Tue, 2011-09-20 at 17:33 +0530, Srikar Dronamraju wrote: > > +static unsigned long xol_take_insn_slot(struct uprobes_xol_area *area) > > +{ > > + unsigned long slot_addr, flags; > > + int slot_nr; > > + > > + do { > > + spin_lock_irqsave(&area->slot_lock, flags); > > + slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE); > > + if (slot_nr < UINSNS_PER_PAGE) { > > + __set_bit(slot_nr, area->bitmap); > > + slot_addr = area->vaddr + > > + (slot_nr * UPROBES_XOL_SLOT_BYTES); > > + atomic_inc(&area->slot_count); > > + } > > + spin_unlock_irqrestore(&area->slot_lock, flags); > > + if (slot_nr >= UINSNS_PER_PAGE) > > + xol_wait_event(area); > > + > > + } while (slot_nr >= UINSNS_PER_PAGE); > > + > > + return slot_addr; > > +} > > Why isn't a find_first_bit() + set_and_test_bit() not sufficient? That > is, what do you need that lock for?
yes, we could do without the lock to. Will do this in the next patchset.
-- Thanks and Regards Srikar
| |