Re: [PATCH] proc: mm: export PTE sizes directly in smaps (v3)

Dave Hansen [off-list ref] writes:

  

 #ifdef CONFIG_HUGETLB_PAGE
+/*
+ * Most architectures have a 1:1 mapping of PTEs to hugetlb page
+ * sizes, but there are some outliers like arm64 that use
+ * multiple hardware PTEs to make a hugetlb "page".  Do not
+ * assume that all 'hpage_size's are not exactly at a page table
+ * size boundary.  Instead, accept arbitrary 'hpage_size's and
+ * assume they are made up of the next-smallest size.  We do not
+ * handle PGD-sized hpages and hugetlb_add_hstate() will WARN()
+ * if it sees one.
+ *
+ * Note also that the page walker code only calls us once per
+ * huge 'struct page', *not* once per PTE in the page tables.
+ */
+static void smaps_hugetlb_present_hpage(struct mem_size_stats *mss,
+					unsigned long hpage_size)
+{
+	if (hpage_size >= PUD_SIZE)
+		mss->rss_pud += hpage_size;
+	else if (hpage_size >= PMD_SIZE)
+		mss->rss_pmd += hpage_size;
+	else
+		mss->rss_pte += hpage_size;
+}

some powerpc platforms have multiple page table entries mapping the same
hugepage and on other, we have a page table entry pointing to something
called hugepaeg directory mapping a set of hugepage. So I am not sure
the above will work for all those ?

Also do we derive pte@<size value> correctly there ?

-aneesh

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