| Message ID | 1463060055-24158-3-git-send-email-bharata@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Thu, May 12, 2016 at 07:04:15PM +0530, Bharata B Rao wrote: > memory_hotplug_max() uses hot_add_drconf_memory_max() to get maxmimum > addressable memory by referring to ibm,dyanamic-memory property. There > are three problems with the current approach: > > 1 hot_add_drconf_memory_max() assumes that ibm,dynamic-memory includes > all the LMBs of the guest, but that is not true for PowerKVM which > populates only DR LMBs (LMBs that can be hotplugged/removed) in that > property. > 2 hot_add_drconf_memory_max() multiplies lmb-size with lmb-count to arrive > at the max possible address. Since ibm,dynamic-memory doesn't include > RMA LMBs, the address thus obtained will be less than the actual max > address. For example, if max possible memory size is 32G, with lmb-size > of 256MB there can be 127 LMBs in ibm,dynamic-memory (1 LMB for RMA > which won't be present here). hot_add_drconf_memory_max() would then > return the max addressable memory as 127 * 256MB = 31.75GB, the max > address should have been 32G which is what ibm,lrdr-capacity shows. > 3 In PowerKVM, there can be a gap between the end of boot time RAM and > beginning of hotplug RAM area. So just multiplying lmb-count with > lmb-size will not provide the correct max possible address for PowerKVM. > > This patch fixes 1 by using ibm,lrdr-capacity property to return the max > addressable memory whenever the property is present. Then it fixes 2 & 3 > by fetching the address of the last LMB in ibm,dynamic-memory property. > > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > arch/powerpc/mm/numa.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c > index 4a87ccb..f8b1da7 100644 > --- a/arch/powerpc/mm/numa.c > +++ b/arch/powerpc/mm/numa.c > @@ -1164,17 +1164,33 @@ int hot_add_scn_to_nid(unsigned long scn_addr) > static u64 hot_add_drconf_memory_max(void) > { > struct device_node *memory = NULL; > + struct device_node *dn = NULL; > unsigned int drconf_cell_cnt = 0; > u64 lmb_size = 0; > const __be32 *dm = NULL; > + const __be64 *lrdr = NULL; > + struct of_drconf_cell drmem; > + > + dn = of_find_node_by_path("/rtas"); > + if (dn) { > + lrdr = of_get_property(dn, "ibm,lrdr-capacity", NULL); > + of_node_put(dn); > + if (lrdr) > + return be64_to_cpup(lrdr); > + } > > memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory"); > if (memory) { > drconf_cell_cnt = of_get_drconf_memory(memory, &dm); > lmb_size = of_get_lmb_size(memory); > + > + /* Advance to the last cell, each cell has 6 32 bit integers */ > + dm += (drconf_cell_cnt - 1) * 6; > + read_drconf_cell(&drmem, &dm); > of_node_put(memory); > + return drmem.base_addr + lmb_size; > } > - return lmb_size * drconf_cell_cnt; > + return 0; > } > > /*
On Thu, 2016-12-05 at 13:34:15 UTC, Bharata B Rao wrote: > memory_hotplug_max() uses hot_add_drconf_memory_max() to get maxmimum > addressable memory by referring to ibm,dyanamic-memory property. There > are three problems with the current approach: > > 1 hot_add_drconf_memory_max() assumes that ibm,dynamic-memory includes > all the LMBs of the guest, but that is not true for PowerKVM which > populates only DR LMBs (LMBs that can be hotplugged/removed) in that > property. > 2 hot_add_drconf_memory_max() multiplies lmb-size with lmb-count to arrive > at the max possible address. Since ibm,dynamic-memory doesn't include > RMA LMBs, the address thus obtained will be less than the actual max > address. For example, if max possible memory size is 32G, with lmb-size > of 256MB there can be 127 LMBs in ibm,dynamic-memory (1 LMB for RMA > which won't be present here). hot_add_drconf_memory_max() would then > return the max addressable memory as 127 * 256MB = 31.75GB, the max > address should have been 32G which is what ibm,lrdr-capacity shows. > 3 In PowerKVM, there can be a gap between the end of boot time RAM and > beginning of hotplug RAM area. So just multiplying lmb-count with > lmb-size will not provide the correct max possible address for PowerKVM. > > This patch fixes 1 by using ibm,lrdr-capacity property to return the max > addressable memory whenever the property is present. Then it fixes 2 & 3 > by fetching the address of the last LMB in ibm,dynamic-memory property. > > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> > Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/45b64ee64970dee9392229302e cheers
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index 4a87ccb..f8b1da7 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -1164,17 +1164,33 @@ int hot_add_scn_to_nid(unsigned long scn_addr) static u64 hot_add_drconf_memory_max(void) { struct device_node *memory = NULL; + struct device_node *dn = NULL; unsigned int drconf_cell_cnt = 0; u64 lmb_size = 0; const __be32 *dm = NULL; + const __be64 *lrdr = NULL; + struct of_drconf_cell drmem; + + dn = of_find_node_by_path("/rtas"); + if (dn) { + lrdr = of_get_property(dn, "ibm,lrdr-capacity", NULL); + of_node_put(dn); + if (lrdr) + return be64_to_cpup(lrdr); + } memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory"); if (memory) { drconf_cell_cnt = of_get_drconf_memory(memory, &dm); lmb_size = of_get_lmb_size(memory); + + /* Advance to the last cell, each cell has 6 32 bit integers */ + dm += (drconf_cell_cnt - 1) * 6; + read_drconf_cell(&drmem, &dm); of_node_put(memory); + return drmem.base_addr + lmb_size; } - return lmb_size * drconf_cell_cnt; + return 0; } /*
memory_hotplug_max() uses hot_add_drconf_memory_max() to get maxmimum addressable memory by referring to ibm,dyanamic-memory property. There are three problems with the current approach: 1 hot_add_drconf_memory_max() assumes that ibm,dynamic-memory includes all the LMBs of the guest, but that is not true for PowerKVM which populates only DR LMBs (LMBs that can be hotplugged/removed) in that property. 2 hot_add_drconf_memory_max() multiplies lmb-size with lmb-count to arrive at the max possible address. Since ibm,dynamic-memory doesn't include RMA LMBs, the address thus obtained will be less than the actual max address. For example, if max possible memory size is 32G, with lmb-size of 256MB there can be 127 LMBs in ibm,dynamic-memory (1 LMB for RMA which won't be present here). hot_add_drconf_memory_max() would then return the max addressable memory as 127 * 256MB = 31.75GB, the max address should have been 32G which is what ibm,lrdr-capacity shows. 3 In PowerKVM, there can be a gap between the end of boot time RAM and beginning of hotplug RAM area. So just multiplying lmb-count with lmb-size will not provide the correct max possible address for PowerKVM. This patch fixes 1 by using ibm,lrdr-capacity property to return the max addressable memory whenever the property is present. Then it fixes 2 & 3 by fetching the address of the last LMB in ibm,dynamic-memory property. Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> --- arch/powerpc/mm/numa.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)