I might be missing something but I couldn't find a way to use the
pagemap information to then look up the NUMA node the respective page is
located on. Especially when analyzing anomalities this is really
useful. The /proc/kpageflags and /proc/kpagecount files don't have that
information.
If this is correct, could the attached patch be considered? It's really
simple and follows the same line as the kpageflags file.
Signed-off-by: Ulrich Drepper <drep...@gmail.com>
Documentation/vm/pagemap.txt | 3 ++
fs/proc/page.c | 50
+++++++++++++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/Documentation/vm/pagemap.txt b/Documentation/vm/pagemap.txt
index 5948e45..413b34c 100644
--- a/Documentation/vm/pagemap.txt
+++ b/Documentation/vm/pagemap.txt
@@ -34,6 +34,9 @@ There are three components to pagemap:
* /proc/kpagecount. This file contains a 64-bit count of the number of
times each page is mapped, indexed by PFN.
+ * /proc/kpagenode. This file contains a 32-bit number of the NUMA node
+ each page is mapped on.
+
* /proc/kpageflags. This file contains a 64-bit set of flags for each
page, indexed by PFN.
diff --git a/fs/proc/page.c b/fs/proc/page.c
index e647c55..65bea9f 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -15,6 +15,9 @@
#define KPMSIZE sizeof(u64)
#define KPMMASK (KPMSIZE - 1)
+#define KNIDSIZE sizeof(s32)
+#define KNIDMASK (KNIDSIZE - 1)
+
/* /proc/kpagecount - an array exposing page counts
*
* Each entry is a u64 representing the corresponding
@@ -212,10 +215,57 @@ static const struct file_operations
proc_kpageflags_operations = {
.read = kpageflags_read,
};
+/* /proc/kpagenode - an array exposing node information for pages
+ *
+ * Each entry is a s32 representing the corresponding
+ * physical page flags.
+ */
+
+static ssize_t kpagenode_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ u64 __user *out = (u64 __user *)buf;
+ unsigned long src = *ppos;
+ unsigned long pfn = src / KNIDSIZE;
+ ssize_t ret = 0;
+
+ count = min_t(unsigned long, count, (max_pfn * KNIDSIZE) - src);
+ if (src & KNIDSIZE || count & KNIDMASK)
+ return -EINVAL;
+
+ while (count > 0) {
+ int nid;
+ if (pfn_valid(pfn))
+ nid = pfn_to_nid(pfn);
+ else
+ nid = -1;
+
+ if (put_user(nid, out)) {
+ ret = -EFAULT;
+ break;
+ }
+
+ pfn++;
+ out++;
+ count -= KNIDSIZE;
+ }
+
+ *ppos += (char __user *)out - buf;
+ if (!ret)
+ ret = (char __user *)out - buf;
+ return ret;
+}
+
+static const struct file_operations proc_kpagenode_operations = {
+ .llseek = mem_lseek,
+ .read = kpagenode_read,
+};
+
static int __init proc_page_init(void)
{
proc_create("kpagecount", S_IRUSR, NULL, &proc_kpagecount_operations);
proc_create("kpageflags", S_IRUSR, NULL, &proc_kpageflags_operations);
+ proc_create("kpagenode", S_IRUSR, NULL, &proc_kpagenode_operations);
return 0;
}
fs_initcall(proc_page_init);
--
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