| Message ID | 1534651288-30306-1-git-send-email-oceanhehy@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | libnvdimm, region_devs: stop NDD_ALIASING bit test if one test pass | expand |
On Sun, 2018-08-19 at 00:01 -0400, Ocean He wrote: > From: Ocean He <hehy1@lenovo.com> > > There is no need to finish entire loop to execute NDD_ALIASING bit > test > against every nvdimm->flags. In practice, all the nd_mapping->nvdimm > have the same flags. > > Because the check of alias is "if (alias)" but not > "if (alias == nd_region->ndr_mappings)", there is no function change > while > just save a few cycles. > > Signed-off-by: Ocean He <hehy1@lenovo.com> > --- > A test to check if all the nd_mapping->nvdimm have the same flags, > using > Lenovo ThinkSystem SR630 and 4.18-rc6. > > # ipmctl show -dimm > > DimmID Capacity HealthState ActionRequired LockState > FWVersion > 0x0021 125.7 > GiB Healthy 0 Disabled 01.00.00.48 > 88 > 0x0121 125.7 > GiB Healthy 0 Disabled 01.00.00.48 > 88 > 0x1021 125.7 > GiB Healthy 0 Disabled 01.00.00.48 > 88 > 0x1121 125.7 > GiB Healthy 0 Disabled 01.00.00.48 > 88 > > # ipmctl create -f -goal -socket 0x0 PersistentMemoryType=AppDirect > > # ipmctl create -f -goal -socket 0x1 PersistentMemoryType=AppDirect > > # reboot, to make goal configuration take effect. > > # ndctl create-namespace -r region0 -s 100m -t pmem -m fsdax > > # ndctl create-namespace -r region1 -s 100m -t pmem -m fsdax > > # reboot and find all the nd_mapping->nvdimm have the same flags. > > drivers/nvdimm/region_devs.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/nvdimm/region_devs.c > b/drivers/nvdimm/region_devs.c > index ec3543b..fc3bc1c 100644 > --- a/drivers/nvdimm/region_devs.c > +++ b/drivers/nvdimm/region_devs.c > @@ -234,8 +234,10 @@ int nd_region_to_nstype(struct nd_region > *nd_region) > struct nd_mapping *nd_mapping = &nd_region- > >mapping[i]; > struct nvdimm *nvdimm = nd_mapping->nvdimm; > > - if (test_bit(NDD_ALIASING, &nvdimm->flags)) > + if (test_bit(NDD_ALIASING, &nvdimm->flags)) > { > alias++; > + break; I think we can go a step further, and instead of the 'break' followed by a check for the 'alias' variable, in the loop, just return ND_DEVICE_NAMESPACE_PMEM if the NDD_ALIASING bit is found for any mapping. Outside the loop, simply return ND_DEVICE_NAMESPACE_IO. That makes it much cleaner and now we can get rid of 'alias' entirely. > + } > } > if (alias) > return ND_DEVICE_NAMESPACE_PMEM;
> -----Original Message----- > From: Verma, Vishal L <vishal.l.verma@intel.com> > Sent: Friday, August 31, 2018 5:51 AM > To: Williams, Dan J <dan.j.williams@intel.com>; ross.zwisler@linux.intel.com; > oceanhehy@gmail.com; Jiang, Dave <dave.jiang@intel.com> > Cc: linux-kernel@vger.kernel.org; linux-nvdimm@lists.01.org; Ocean HY1 He > <hehy1@lenovo.com> > Subject: [External] Re: [PATCH] libnvdimm, region_devs: stop NDD_ALIASING > bit test if one test pass > > > On Sun, 2018-08-19 at 00:01 -0400, Ocean He wrote: > > From: Ocean He <hehy1@lenovo.com> > > > > There is no need to finish entire loop to execute NDD_ALIASING bit > > test > > against every nvdimm->flags. In practice, all the nd_mapping->nvdimm > > have the same flags. > > > > Because the check of alias is "if (alias)" but not > > "if (alias == nd_region->ndr_mappings)", there is no function change > > while > > just save a few cycles. > > > > Signed-off-by: Ocean He <hehy1@lenovo.com> > > --- > > A test to check if all the nd_mapping->nvdimm have the same flags, > > using > > Lenovo ThinkSystem SR630 and 4.18-rc6. > > > > # ipmctl show -dimm > > > > DimmID Capacity HealthState ActionRequired LockState > > FWVersion > > 0x0021 125.7 > > GiB Healthy 0 Disabled 01.00.00.48 > > 88 > > 0x0121 125.7 > > GiB Healthy 0 Disabled 01.00.00.48 > > 88 > > 0x1021 125.7 > > GiB Healthy 0 Disabled 01.00.00.48 > > 88 > > 0x1121 125.7 > > GiB Healthy 0 Disabled 01.00.00.48 > > 88 > > > > # ipmctl create -f -goal -socket 0x0 PersistentMemoryType=AppDirect > > > > # ipmctl create -f -goal -socket 0x1 PersistentMemoryType=AppDirect > > > > # reboot, to make goal configuration take effect. > > > > # ndctl create-namespace -r region0 -s 100m -t pmem -m fsdax > > > > # ndctl create-namespace -r region1 -s 100m -t pmem -m fsdax > > > > # reboot and find all the nd_mapping->nvdimm have the same flags. > > > > drivers/nvdimm/region_devs.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/nvdimm/region_devs.c > > b/drivers/nvdimm/region_devs.c > > index ec3543b..fc3bc1c 100644 > > --- a/drivers/nvdimm/region_devs.c > > +++ b/drivers/nvdimm/region_devs.c > > @@ -234,8 +234,10 @@ int nd_region_to_nstype(struct nd_region > > *nd_region) > > struct nd_mapping *nd_mapping = &nd_region- > > >mapping[i]; > > struct nvdimm *nvdimm = nd_mapping->nvdimm; > > > > - if (test_bit(NDD_ALIASING, &nvdimm->flags)) > > + if (test_bit(NDD_ALIASING, &nvdimm->flags)) > > { > > alias++; > > + break; > > I think we can go a step further, and instead of the 'break' followed > by a check for the 'alias' variable, in the loop, just return > ND_DEVICE_NAMESPACE_PMEM if the NDD_ALIASING bit is found for any > mapping. Outside the loop, simply return ND_DEVICE_NAMESPACE_IO. That > makes it much cleaner and now we can get rid of 'alias' entirely. > Hi Vishal, Thanks for comments and I would send version 2 patch later. Ocean. > > + } > > } > > if (alias) > > return ND_DEVICE_NAMESPACE_PMEM;
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c index ec3543b..fc3bc1c 100644 --- a/drivers/nvdimm/region_devs.c +++ b/drivers/nvdimm/region_devs.c @@ -234,8 +234,10 @@ int nd_region_to_nstype(struct nd_region *nd_region) struct nd_mapping *nd_mapping = &nd_region->mapping[i]; struct nvdimm *nvdimm = nd_mapping->nvdimm; - if (test_bit(NDD_ALIASING, &nvdimm->flags)) + if (test_bit(NDD_ALIASING, &nvdimm->flags)) { alias++; + break; + } } if (alias) return ND_DEVICE_NAMESPACE_PMEM;