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libnvdimm, pmem: disable dax flushing when pmem is fronting a volatile region 

The pmem driver attaches to both persistent and volatile memory ranges
advertised by the ACPI NFIT. When the region is volatile it is redundant
to spend cycles flushing caches at fsync(). Check if the hosting region
is volatile and do not set dax_write_cache() if it is.

Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2017-06-09 09:46:50 -07:00
parent 6e0c90d691
commit 0b277961f4
3 changed files with 15 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/nvdimm/pmem.c
View File

@ -284,10 +284,10 @@ static int pmem_attach_disk(struct device *dev,
struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
struct nd_region *nd_region = to_nd_region(dev->parent);
struct vmem_altmap __altmap, *altmap = NULL;
int nid = dev_to_node(dev), fua, wbc;
struct resource *res = &nsio->res;
struct nd_pfn *nd_pfn = NULL;
struct dax_device *dax_dev;
int nid = dev_to_node(dev);
struct nd_pfn_sb *pfn_sb;
struct pmem_device *pmem;
struct resource pfn_res;
@ -314,9 +314,12 @@ static int pmem_attach_disk(struct device *dev,
dev_set_drvdata(dev, pmem);
pmem->phys_addr = res->start;
pmem->size = resource_size(res);
if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE)
|| nvdimm_has_flush(nd_region) < 0)
fua = nvdimm_has_flush(nd_region);
if (!IS_ENABLED(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) || fua < 0) {
dev_warn(dev, "unable to guarantee persistence of writes\n");
fua = 0;
}
wbc = nvdimm_has_cache(nd_region);
if (!devm_request_mem_region(dev, res->start, resource_size(res),
dev_name(&ndns->dev))) {
@ -360,7 +363,7 @@ static int pmem_attach_disk(struct device *dev,
return PTR_ERR(addr);
pmem->virt_addr = addr;
blk_queue_write_cache(q, true, true);
blk_queue_write_cache(q, wbc, fua);
blk_queue_make_request(q, pmem_make_request);
blk_queue_physical_block_size(q, PAGE_SIZE);
blk_queue_max_hw_sectors(q, UINT_MAX);
@ -390,7 +393,7 @@ static int pmem_attach_disk(struct device *dev,
put_disk(disk);
return -ENOMEM;
}
dax_write_cache(dax_dev, true);
dax_write_cache(dax_dev, wbc);
pmem->dax_dev = dax_dev;
gendev = disk_to_dev(disk);

6
drivers/nvdimm/region_devs.c
View File

@ -1060,6 +1060,12 @@ int nvdimm_has_flush(struct nd_region *nd_region)
}
EXPORT_SYMBOL_GPL(nvdimm_has_flush);
int nvdimm_has_cache(struct nd_region *nd_region)
{
return is_nd_pmem(&nd_region->dev);
}
EXPORT_SYMBOL_GPL(nvdimm_has_cache);
void __exit nd_region_devs_exit(void)
{
ida_destroy(&region_ida);

1
include/linux/libnvdimm.h
View File

@ -165,4 +165,5 @@ void nd_region_release_lane(struct nd_region *nd_region, unsigned int lane);
u64 nd_fletcher64(void *addr, size_t len, bool le);
void nvdimm_flush(struct nd_region *nd_region);
int nvdimm_has_flush(struct nd_region *nd_region);
int nvdimm_has_cache(struct nd_region *nd_region);
#endif /* __LIBNVDIMM_H__ */