Messages in this thread | | | Date | Fri, 29 May 2020 13:57:40 -0700 | From | Minchan Kim <> | Subject | Re: [PATCH v3 7/7] zram: Use local lock to protect per-CPU data |
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On Wed, May 27, 2020 at 10:11:19PM +0200, Sebastian Andrzej Siewior wrote: > From: Mike Galbraith <umgwanakikbuti@gmail.com> > > The zcomp driver 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. > > [bigeasy: Use local_lock(), description, drop reordering] > > Cc: Minchan Kim <minchan@kernel.org> > Cc: Nitin Gupta <ngupta@vflare.org> > Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> > Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Minchan Kim <minchan@kernel.org>
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