Re: [RFC PATCH v1 1/5] locking/atomic: Implement atomic_fetch_and_or
From: hev <hidden>
Date: 2021-07-29 01:58:16
Hi, Peter, On Wed, Jul 28, 2021 at 9:21 PM Peter Zijlstra [off-list ref] wrote:
On Wed, Jul 28, 2021 at 03:16:54PM +0200, Peter Zijlstra wrote:quoted
On Wed, Jul 28, 2021 at 02:58:35PM +0200, Peter Zijlstra wrote:quoted
The below isn't quite right, because it'll use try_cmpxchg() for atomic_andnot_or(), which by being a void atomic should be _relaxed. I'm not entirely sure how to make that happen in a hurry. ---This seems to do the trick.Mark suggested this, which is probably nicer still.
Wow, Amazing! so the architecture dependent can be implemented one by one. Regards Rui
quoted hunk ↗ jump to hunk
---diff --git a/scripts/atomic/atomics.tbl b/scripts/atomic/atomics.tbl index fbee2f6190d9..3aaa0caa6b2d 100755 --- a/scripts/atomic/atomics.tbl +++ b/scripts/atomic/atomics.tbl@@ -39,3 +39,4 @@ inc_not_zero b v inc_unless_negative b v dec_unless_positive b v dec_if_positive i v +andnot_or vF v i:m i:odiff --git a/scripts/atomic/fallbacks/andnot_or b/scripts/atomic/fallbacks/andnot_or new file mode 100644 index 000000000000..0fb3a728c0ff --- /dev/null +++ b/scripts/atomic/fallbacks/andnot_or@@ -0,0 +1,24 @@ +local try_order=${order} + +# +# non-value returning atomics are implicity relaxed +# +if [ -z "${retstmt}" ]; then + try_order="_relaxed" +fi + +cat <<EOF +static __always_inline ${ret} +arch_${atomic}_${pfx}andnot_or${sfx}${order}(${atomic}_t *v, ${int} m, ${int} o) +{ + ${retstmt}({ + ${int} N, O = atomic_read(v); + do { + N = O; + N &= ~m; + N |= o; + } while (!arch_${atomic}_try_cmpxchg${try_order}(v, &O, N)); + O; + }); +} +EOFdiff --git a/scripts/atomic/fallbacks/fetch_andnot_or b/scripts/atomic/fallbacks/fetch_andnot_or deleted file mode 100644 index e69de29bb2d1..000000000000