This patch allows the memory removed by memtrace to be readded to the
kernel. So now you don't have to reboot your system to add the memory
back to the kernel or to have a different amount of memory removed.
Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com>
Tested-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
debugfs doesn't support mmap(), so this code is never used.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently memtrace doesn't build if NUMA=n:
In function ‘memtrace_alloc_node’:
arch/powerpc/platforms/powernv/memtrace.c:134:6:
error: the address of ‘contig_page_data’ will always evaluate as ‘true’
if (!NODE_DATA(nid) || !node_spanned_pages(nid))
^
This is because for NUMA=n NODE_DATA(nid) points to an always
allocated structure, contig_page_data.
But even in the NUMA=y case memtrace_alloc_node() is only called for
online nodes, and we should always have a NODE_DATA() allocated for an
online node. So remove the (hopefully) overly paranoid check, which
also means we can build when NUMA=n.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Don't do this via custom code, instead now that we have support in the
arch hotplug/hotunplug code, rely on those routines to do the right
thing.
The existing flush doesn't work because it uses ppc64_caches.l1d.size
instead of ppc64_caches.l1d.line_size.
Fixes: 9d5171a8f2 ("powerpc/powernv: Enable removal of memory for in memory tracing")
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Reviewed-by: Rashmica Gupta <rashmica.g@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The hardware trace macro feature requires access to a chunk of real
memory. This patch provides a debugfs interface to do this. By
writing an integer containing the size of memory to be unplugged into
/sys/kernel/debug/powerpc/memtrace/enable, the code will attempt to
remove that much memory from the end of each NUMA node.
This patch also adds additional debugsfs files for each node that
allows the tracer to interact with the removed memory, as well as
a trace file that allows userspace to read the generated trace.
Note that this patch does not invoke the hardware trace macro, it
only allows memory to be removed during runtime for the trace macro
to utilise.
Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com>
[mpe: Minor formatting etc fixups]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Rashmica Gupta