[RFC PATCH 3/8] dax/kmem: add the reclaim opt-in (CAP_RECLAIM) for private nodes
Gregory Price <[email protected]>
| Newsgroups | org.kernel.vger.linux-cxl,dev.linux.lists.nvdimm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Add the first per-service opt-in for a private node: "reclaim". Also introduces the KMEM_PRIVATE_CAP_ATTR() helper for future bits. Sets NODE_PRIVATE_CAP_RECLAIM for the device's private node. A private kmem node opted into reclaim recovers THP compatibility. Signed-off-by: Gregory Price <[email protected]> --- drivers/dax/kmem.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c index c4c18aeb43c69..cf6cb927e5ed5 100644 --- a/drivers/dax/kmem.c +++ b/drivers/dax/kmem.c @@ -117,7 +117,7 @@ static int kmem_anon_mmap(struct file *filp, struct vm_area_struct *vma) * Without reclaim/compaction, high-order allocations can fail despite * memory still being available. Can be relaxed with reclaim support. */ - if (data->private) + if (!node_allows_reclaim(data->numa_node)) vm_flags_set(vma, VM_NOHUGEPAGE); mpol_get(data->policy); kmem_vma_set_policy(vma, data->policy); @@ -595,8 +595,44 @@ static ssize_t dax_file_store(struct device *dev, struct device_attribute *attr, } static DEVICE_ATTR_RW(dax_file); +/* NODE_PRIVATE_CAP_* opt-in toggles - captured in data->caps */ +#define KMEM_PRIVATE_CAP_ATTR(name, CAP) \ +static ssize_t name##_show(struct device *dev, \ + struct device_attribute *attr, char *buf) \ +{ \ + struct dax_kmem_data *data = dev_get_drvdata(dev); \ + \ + return sysfs_emit(buf, "%d\n", !!(data->caps & (CAP))); \ +} \ +static ssize_t name##_store(struct device *dev, \ + struct device_attribute *attr, \ + const char *buf, size_t len) \ +{ \ + struct dax_kmem_data *data = dev_get_drvdata(dev); \ + bool enable; \ + ssize_t rc; \ + \ + rc = kstrtobool(buf, &enable); \ + if (rc) \ + return rc; \ + \ + guard(mutex)(&data->lock); \ + \ + if (data->state != DAX_KMEM_UNPLUGGED) \ + return -EBUSY; \ + if (enable) \ + data->caps |= (CAP); \ + else \ + data->caps &= ~(CAP); \ + return len; \ +} \ +static DEVICE_ATTR_RW(name) + +KMEM_PRIVATE_CAP_ATTR(reclaim, NODE_PRIVATE_CAP_RECLAIM); + /* Per-service opt-ins. Visibility toggled by 'private' control */ static struct attribute *dax_kmem_private_attrs[] = { + &dev_attr_reclaim.attr, NULL, }; static const struct attribute_group dax_kmem_private_group = { -- 2.53.0-Meta