| Message ID | 20180712011954.GC6742@localhost.localdomain (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 07/12/18 at 09:19am, Chao Fan wrote: > 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 <bhe@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 <bhe@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. Might be not. Need consider usable_startpfn and kernel_pfn are in the same node, or in different node, two cases. I will correct code after fix the compiling error. > > > > > >+ /* > >+ * 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 > > > > > > > >
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;