linux_dsm_epyc7002/drivers/s390
Julian Wiedmann c119a8a3c3 s390/qdio: fine-tune SLSB update
xchg() for a single-byte location assembles to a 4-byte Compare&Swap,
wrapped into a non-trivial amount of retry code that deals with
concurrent modifications to the unaffected bytes.

Change it to a simple byte-store, but preserve the memory ordering
semantics that the CS provided.
This simplifies the generated code for a hot path, and in theory also
allows us to amortize the memory barriers over multiple SLSB updates.

CC: Andreas Krebbel <krebbel@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-06-16 13:44:03 +02:00
..
block
char
cio s390/qdio: fine-tune SLSB update 2020-06-16 13:44:03 +02:00
crypto
net s390 updates for the 5.8 merge window 2020-06-08 12:05:31 -07:00
scsi
virtio
Makefile