Messages in this thread | | | Date | Thu, 21 Nov 2019 21:19:51 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v10 6/6] x86/split_lock: Enable split lock detection by kernel parameter |
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On Thu, Nov 21, 2019 at 12:25:35PM -0800, Fenghua Yu wrote:
> > > We are working on a separate patch set to fix all split lock issues > > > in atomic bitops. Per Peter Anvin and Tony Luck suggestions: > > > 1. Still keep the byte optimization if nr is constant. No split lock. > > > 2. If type of *addr is unsigned long, do quadword atomic instruction > > > on addr. No split lock. > > > 3. If type of *addr is unsigned int, do word atomic instruction > > > on addr. No split lock. > > > 4. Otherwise, re-calculate addr to point the 32-bit address which contains > > > the bit and operate on the bit. No split lock.
> Actually we only find 8 places calling atomic bitops using type casting > "unsigned long *". After above changes, other 8 patches remove the type > castings and then split lock free in atomic bitops in the current kernel.
Those above changes are never going to happen.
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