[PATCH v8 15/20] x86: mm: Don't display pages which aren't present in debugfs

Steven Price
2019-04-03T14:18:14Z

For the /sys/kernel/debug/page_tables/ files, rather than outputing a
mostly empty line when a block of memory isn't present just skip the
line. This keeps the output shorter and will help with a future change
switching to using the generic page walk code as we no longer care about
the 'level' that the page table holes are at.

Signed-off-by: Steven Price <steven.price@arm.com>
---
arch/x86/mm/dump_pagetables.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c
index ca270fb00805..e2b53db92c34 100644
--- a/arch/x86/mm/dump_pagetables.c
+++ b/arch/x86/mm/dump_pagetables.c
@@ -304,8 +304,8 @@ static void note_page(struct seq_file *m, struct pg_state *st,
/*
* Now print the actual finished series
*/
- if (!st->marker->max_lines ||
- st->lines < st->marker->max_lines) {
+ if ((cur & _PAGE_PRESENT) && (!st->marker->max_lines ||
+ st->lines < st->marker->max_lines)) {
pt_dump_seq_printf(m, st->to_dmesg,
"0x%0*lx-0x%0*lx ",
width, st->start_address,
@@ -321,7 +321,8 @@ static void note_page(struct seq_file *m, struct pg_state *st,
printk_prot(m, st->current_prot, st->level,
st->to_dmesg);
}
- st->lines++;
+ if (cur & _PAGE_PRESENT)
+ st->lines++;

/*
* We print markers for special areas of address space,
--
2.20.1