> From: "Luis Claudio R. Goncalves" <lgoncalv@xxxxxxxxxx> > zwap uses per-CPU compression. The per-CPU data pointer is acquired with > get_cpu_ptr() which implicitly disables preemption. It allocates memory inside the preempt disabled region which conflicts with the PREEMPT_RT semantics. > Replace the implicit preemption control with an explicit local lock. > This allows RT kernels to substitute it with a real per CPU lock, which serializes the access but keeps the code section preemptible. On non RT kernels this maps to preempt_disable() as before, i.e. no functional change. Hi Luis, In the below patch, in order to use the acomp APIs to leverage the power of hardware compressors. I have moved to mutex: https://marc.info/?l=linux-crypto-vger&m=158941285830302&w=2 https://marc.info/?l=linux-crypto-vger&m=158941287930311&w=2 so once we get some progress on that one, I guess we don't need a special patch for RT any more. > [bigeasy: Use local_lock(), additional hunks, patch description] > Cc: Seth Jennings <sjenning@xxxxxxxxxx> > Cc: Dan Streetman <ddstreet@xxxxxxxx> > Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: linux-mm@xxxxxxxxx > Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@xxxxxxxxxx> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> > --- > mm/zswap.c | 23 ++++++++++++++--------- > 1 file changed, 14 insertions(+), 9 deletions(-) Thanks Barry
