On Wed, Jul 11, 2018 at 08:40:08PM +0800, Baoquan He wrote:
>Please try this v3 patch:
>
>From 9850d3de9c02e570dc7572069a9749a8add4c4c7 Mon Sep 17 00:00:00 2001
>From: Baoquan He <b...@redhat.com>
>Date: Wed, 11 Jul 2018 20:31:51 +0800
>Subject: [PATCH v3] mm, page_alloc: find movable zone after kernel text
>
>In find_zone_movable_pfns_for_nodes(), when try to find the starting
>PFN movable zone begins in each node, kernel text position is not
>considered. KASLR may put kernel after which movable zone begins.
>
>Fix it by finding movable zone after kernel text on that node.
>
>Signed-off-by: Baoquan He <b...@redhat.com>
>---
> mm/page_alloc.c | 20 +++++++++++++++-----
> 1 file changed, 15 insertions(+), 5 deletions(-)
>
>diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>index 1521100..390eb35 100644
>--- a/mm/page_alloc.c
>+++ b/mm/page_alloc.c
>@@ -6547,7 +6547,7 @@ static unsigned long __init
>early_calculate_totalpages(void)
> static void __init find_zone_movable_pfns_for_nodes(void)
> {
> int i, nid;
>- unsigned long usable_startpfn;
>+ unsigned long usable_startpfn, real_startpfn;
> unsigned long kernelcore_node, kernelcore_remaining;
> /* save the state before borrow the nodemask */
> nodemask_t saved_node_state = node_states[N_MEMORY];
>@@ -6681,10 +6681,20 @@ static void __init
>find_zone_movable_pfns_for_nodes(void)
> if (start_pfn >= end_pfn)
> continue;
Hi Baoquan,
Thanks for your quick reply and PATCH.
I think it can work well after reviewing the code. But I think the new
variable 'real_startpfn' is unnecessary. How about this:
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6d00f746c2fd..0fc9c4283947 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6492,6 +6492,10 @@ static void __init find_zone_movable_pfns_for_nodes(void)
if (start_pfn >= end_pfn)
continue;
+ if (pfn_to_nid(PFN_UP(_etext)) == i)
+ usable_startpfn = max(usable_startpfn,
+ PFN_UP(_etext));
+
/* Account for what is only usable for kernelcore */
if (start_pfn < usable_startpfn) {
unsigned long kernel_pages;
I think the logic of these two method are the same, and this method
change less code. If I am wrong, please let me know.
Thanks,
Chao Fan
>
>+ /*
>+ * KASLR may put kernel near tail of node memory,
>+ * start after kernel on that node to find PFN
>+ * which zone begins.
>+ */
>+ if (pfn_to_nid(PFN_UP(_etext)) == i)
>+ real_startpfn = max(usable_startpfn,
>+ PFN_UP(_etext))
>+ else
>+ real_startpfn = usable_startpfn;
> /* Account for what is only usable for kernelcore */
>- if (start_pfn < usable_startpfn) {
>+ if (start_pfn < real_startpfn) {
> unsigned long kernel_pages;
>- kernel_pages = min(end_pfn, usable_startpfn)
>+ kernel_pages = min(end_pfn, real_startpfn)
> - start_pfn;
>
> kernelcore_remaining -= min(kernel_pages,
>@@ -6693,7 +6703,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
> required_kernelcore);
>
> /* Continue if range is now fully accounted */
>- if (end_pfn <= usable_startpfn) {
>+ if (end_pfn <= real_startpfn) {
>
> /*
> * Push zone_movable_pfn to the end so
>@@ -6704,7 +6714,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
> zone_movable_pfn[nid] = end_pfn;
> continue;
> }
>- start_pfn = usable_startpfn;
>+ start_pfn = real_startpfn;
> }
>
> /*
>--
>2.1.0
>
>
>
