Re: [PATCH v3 2/2] mm: fix initialization of struct page for holes in memory layout
On Mon, Feb 01, 2021 at 05:39:58PM +0800, Baoquan He wrote:
> On 02/01/21 at 10:14am, David Hildenbrand wrote:
> > On 11.01.21 20:40, Mike Rapoport wrote:
> > > +
> > > +static void __init init_unavailable_mem(void)
> > > +{
> > > + int zone;
> > > +
> > > + for (zone = 0; zone < ZONE_MOVABLE; zone++)
> > > + init_zone_unavailable_mem(zone);
> >
> > Why < ZONE_MOVABLE?
> >
> > I remember we can have memory holes inside the movable zone when messing
> > with "movablecore" cmdline parameter.
>
> Maybe because we haven't initialized MOABLE zone info at this time.
We already have zone_movable_pfn initialized at this point.
So if there is a possibility for holes in the movable zone, we should take
care of it.
--
Sincerely yours,
Mike.
Re: [PATCH v3 2/2] mm: fix initialization of struct page for holes in memory layout
On 02/01/21 at 10:14am, David Hildenbrand wrote:
> On 11.01.21 20:40, Mike Rapoport wrote:
> > From: Mike Rapoport
> >
> > There could be struct pages that are not backed by actual physical memory.
> > This can happen when the actual memory bank is not a multiple of
> > SECTION_SIZE or when an architecture does not register memory holes
> > reserved by the firmware as memblock.memory.
> >
> > Such pages are currently initialized using init_unavailable_mem() function
> > that iterates through PFNs in holes in memblock.memory and if there is a
> > struct page corresponding to a PFN, the fields if this page are set to
> > default values and the page is marked as Reserved.
> >
> > init_unavailable_mem() does not take into account zone and node the page
> > belongs to and sets both zone and node links in struct page to zero.
> >
> > On a system that has firmware reserved holes in a zone above ZONE_DMA, for
> > instance in a configuration below:
> >
> > # grep -A1 E820 /proc/iomem
> > 7a17b000-7a216fff : Unknown E820 type
> > 7a217000-7bff : System RAM
> >
> > unset zone link in struct page will trigger
> >
> > VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
> >
> > because there are pages in both ZONE_DMA32 and ZONE_DMA (unset zone link in
> > struct page) in the same pageblock.
> >
> > Update init_unavailable_mem() to use zone constraints defined by an
> > architecture to properly setup the zone link and use node ID of the
> > adjacent range in memblock.memory to set the node link.
> >
> > Fixes: 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather
> > that check each PFN")
> > Reported-by: Andrea Arcangeli
> > Signed-off-by: Mike Rapoport
> > ---
> > mm/page_alloc.c | 84 +
> > 1 file changed, 50 insertions(+), 34 deletions(-)
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index bdbec4c98173..0b56c3ca354e 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -7077,23 +7077,26 @@ void __init free_area_init_memoryless_node(int nid)
> >* Initialize all valid struct pages in the range [spfn, epfn) and mark
> > them
> >* PageReserved(). Return the number of struct pages that were
> > initialized.
> >*/
> > -static u64 __init init_unavailable_range(unsigned long spfn, unsigned long
> > epfn)
> > +static u64 __init init_unavailable_range(unsigned long spfn, unsigned long
> > epfn,
> > +int zone, int nid)
> > {
> > - unsigned long pfn;
> > + unsigned long pfn, zone_spfn, zone_epfn;
> > u64 pgcnt = 0;
> > + zone_spfn = arch_zone_lowest_possible_pfn[zone];
> > + zone_epfn = arch_zone_highest_possible_pfn[zone];
> > +
> > + spfn = clamp(spfn, zone_spfn, zone_epfn);
> > + epfn = clamp(epfn, zone_spfn, zone_epfn);
> > +
> > for (pfn = spfn; pfn < epfn; pfn++) {
> > if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
> > pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
> > + pageblock_nr_pages - 1;
> > continue;
> > }
> > - /*
> > -* Use a fake node/zone (0) for now. Some of these pages
> > -* (in memblock.reserved but not in memblock.memory) will
> > -* get re-initialized via reserve_bootmem_region() later.
> > -*/
> > - __init_single_page(pfn_to_page(pfn), pfn, 0, 0);
> > +
> > + __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
> > __SetPageReserved(pfn_to_page(pfn));
> > pgcnt++;
> > }
> > @@ -7102,51 +7105,64 @@ static u64 __init init_unavailable_range(unsigned
> > long spfn, unsigned long epfn)
> > }
> > /*
> > - * Only struct pages that are backed by physical memory are zeroed and
> > - * initialized by going through __init_single_page(). But, there are some
> > - * struct pages which are reserved in memblock allocator and their fields
> > - * may be accessed (for example page_to_pfn() on some configuration
> > accesses
> > - * flags). We must explicitly initialize those struct pages.
> > + * Only struct pages that correspond to ranges defined by memblock.memory
> > + * are zeroed and initialized by going through __init_single_page() during
> > + * memmap_init().
> > + *
> > + * But, there could be struct pages that correspond to holes in
> > + * memblock.memory. This can happen because of the following reasons:
> > + * - phyiscal memory bank size is not necessarily the exact multiple of the
> > + * arbitrary section size
> > + * - early reserved memory may not be listed in memblock.memory
> > + * - memory layouts defined with memmap= kernel parameter may not align
> > + * nicely with memmap sections
> >*
> > - * This function also addresses a similar issue where struct pages are left
> > - * uninitialized because the physical address range is not covered by
> > - * memblock.memory or
Re: [PATCH v3 2/2] mm: fix initialization of struct page for holes in memory layout
On 11.01.21 20:40, Mike Rapoport wrote:
From: Mike Rapoport
There could be struct pages that are not backed by actual physical memory.
This can happen when the actual memory bank is not a multiple of
SECTION_SIZE or when an architecture does not register memory holes
reserved by the firmware as memblock.memory.
Such pages are currently initialized using init_unavailable_mem() function
that iterates through PFNs in holes in memblock.memory and if there is a
struct page corresponding to a PFN, the fields if this page are set to
default values and the page is marked as Reserved.
init_unavailable_mem() does not take into account zone and node the page
belongs to and sets both zone and node links in struct page to zero.
On a system that has firmware reserved holes in a zone above ZONE_DMA, for
instance in a configuration below:
# grep -A1 E820 /proc/iomem
7a17b000-7a216fff : Unknown E820 type
7a217000-7bff : System RAM
unset zone link in struct page will trigger
VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
because there are pages in both ZONE_DMA32 and ZONE_DMA (unset zone link in
struct page) in the same pageblock.
Update init_unavailable_mem() to use zone constraints defined by an
architecture to properly setup the zone link and use node ID of the
adjacent range in memblock.memory to set the node link.
Fixes: 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather that
check each PFN")
Reported-by: Andrea Arcangeli
Signed-off-by: Mike Rapoport
---
mm/page_alloc.c | 84 +
1 file changed, 50 insertions(+), 34 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bdbec4c98173..0b56c3ca354e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7077,23 +7077,26 @@ void __init free_area_init_memoryless_node(int nid)
* Initialize all valid struct pages in the range [spfn, epfn) and mark them
* PageReserved(). Return the number of struct pages that were initialized.
*/
-static u64 __init init_unavailable_range(unsigned long spfn, unsigned long
epfn)
+static u64 __init init_unavailable_range(unsigned long spfn, unsigned long
epfn,
+int zone, int nid)
{
- unsigned long pfn;
+ unsigned long pfn, zone_spfn, zone_epfn;
u64 pgcnt = 0;
+ zone_spfn = arch_zone_lowest_possible_pfn[zone];
+ zone_epfn = arch_zone_highest_possible_pfn[zone];
+
+ spfn = clamp(spfn, zone_spfn, zone_epfn);
+ epfn = clamp(epfn, zone_spfn, zone_epfn);
+
for (pfn = spfn; pfn < epfn; pfn++) {
if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
+ pageblock_nr_pages - 1;
continue;
}
- /*
-* Use a fake node/zone (0) for now. Some of these pages
-* (in memblock.reserved but not in memblock.memory) will
-* get re-initialized via reserve_bootmem_region() later.
-*/
- __init_single_page(pfn_to_page(pfn), pfn, 0, 0);
+
+ __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
__SetPageReserved(pfn_to_page(pfn));
pgcnt++;
}
@@ -7102,51 +7105,64 @@ static u64 __init init_unavailable_range(unsigned long
spfn, unsigned long epfn)
}
/*
- * Only struct pages that are backed by physical memory are zeroed and
- * initialized by going through __init_single_page(). But, there are some
- * struct pages which are reserved in memblock allocator and their fields
- * may be accessed (for example page_to_pfn() on some configuration accesses
- * flags). We must explicitly initialize those struct pages.
+ * Only struct pages that correspond to ranges defined by memblock.memory
+ * are zeroed and initialized by going through __init_single_page() during
+ * memmap_init().
+ *
+ * But, there could be struct pages that correspond to holes in
+ * memblock.memory. This can happen because of the following reasons:
+ * - phyiscal memory bank size is not necessarily the exact multiple of the
+ * arbitrary section size
+ * - early reserved memory may not be listed in memblock.memory
+ * - memory layouts defined with memmap= kernel parameter may not align
+ * nicely with memmap sections
*
- * This function also addresses a similar issue where struct pages are left
- * uninitialized because the physical address range is not covered by
- * memblock.memory or memblock.reserved. That could happen when memblock
- * layout is manually configured via memmap=, or when the highest physical
- * address (max_pfn) does not end on a section boundary.
+ * Explicitly initialize those struct pages so that:
+ * - PG_Reserved is set
+ * - zone link is set accorging to the architecture constrains
+ * - node is set to node id of the next populated
[PATCH v3 2/2] mm: fix initialization of struct page for holes in memory layout
From: Mike Rapoport
There could be struct pages that are not backed by actual physical memory.
This can happen when the actual memory bank is not a multiple of
SECTION_SIZE or when an architecture does not register memory holes
reserved by the firmware as memblock.memory.
Such pages are currently initialized using init_unavailable_mem() function
that iterates through PFNs in holes in memblock.memory and if there is a
struct page corresponding to a PFN, the fields if this page are set to
default values and the page is marked as Reserved.
init_unavailable_mem() does not take into account zone and node the page
belongs to and sets both zone and node links in struct page to zero.
On a system that has firmware reserved holes in a zone above ZONE_DMA, for
instance in a configuration below:
# grep -A1 E820 /proc/iomem
7a17b000-7a216fff : Unknown E820 type
7a217000-7bff : System RAM
unset zone link in struct page will trigger
VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
because there are pages in both ZONE_DMA32 and ZONE_DMA (unset zone link in
struct page) in the same pageblock.
Update init_unavailable_mem() to use zone constraints defined by an
architecture to properly setup the zone link and use node ID of the
adjacent range in memblock.memory to set the node link.
Fixes: 73a6e474cb37 ("mm: memmap_init: iterate over memblock regions rather
that check each PFN")
Reported-by: Andrea Arcangeli
Signed-off-by: Mike Rapoport
---
mm/page_alloc.c | 84 +
1 file changed, 50 insertions(+), 34 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bdbec4c98173..0b56c3ca354e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -7077,23 +7077,26 @@ void __init free_area_init_memoryless_node(int nid)
* Initialize all valid struct pages in the range [spfn, epfn) and mark them
* PageReserved(). Return the number of struct pages that were initialized.
*/
-static u64 __init init_unavailable_range(unsigned long spfn, unsigned long
epfn)
+static u64 __init init_unavailable_range(unsigned long spfn, unsigned long
epfn,
+int zone, int nid)
{
- unsigned long pfn;
+ unsigned long pfn, zone_spfn, zone_epfn;
u64 pgcnt = 0;
+ zone_spfn = arch_zone_lowest_possible_pfn[zone];
+ zone_epfn = arch_zone_highest_possible_pfn[zone];
+
+ spfn = clamp(spfn, zone_spfn, zone_epfn);
+ epfn = clamp(epfn, zone_spfn, zone_epfn);
+
for (pfn = spfn; pfn < epfn; pfn++) {
if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
+ pageblock_nr_pages - 1;
continue;
}
- /*
-* Use a fake node/zone (0) for now. Some of these pages
-* (in memblock.reserved but not in memblock.memory) will
-* get re-initialized via reserve_bootmem_region() later.
-*/
- __init_single_page(pfn_to_page(pfn), pfn, 0, 0);
+
+ __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
__SetPageReserved(pfn_to_page(pfn));
pgcnt++;
}
@@ -7102,51 +7105,64 @@ static u64 __init init_unavailable_range(unsigned long
spfn, unsigned long epfn)
}
/*
- * Only struct pages that are backed by physical memory are zeroed and
- * initialized by going through __init_single_page(). But, there are some
- * struct pages which are reserved in memblock allocator and their fields
- * may be accessed (for example page_to_pfn() on some configuration accesses
- * flags). We must explicitly initialize those struct pages.
+ * Only struct pages that correspond to ranges defined by memblock.memory
+ * are zeroed and initialized by going through __init_single_page() during
+ * memmap_init().
+ *
+ * But, there could be struct pages that correspond to holes in
+ * memblock.memory. This can happen because of the following reasons:
+ * - phyiscal memory bank size is not necessarily the exact multiple of the
+ * arbitrary section size
+ * - early reserved memory may not be listed in memblock.memory
+ * - memory layouts defined with memmap= kernel parameter may not align
+ * nicely with memmap sections
*
- * This function also addresses a similar issue where struct pages are left
- * uninitialized because the physical address range is not covered by
- * memblock.memory or memblock.reserved. That could happen when memblock
- * layout is manually configured via memmap=, or when the highest physical
- * address (max_pfn) does not end on a section boundary.
+ * Explicitly initialize those struct pages so that:
+ * - PG_Reserved is set
+ * - zone link is set accorging to the architecture constrains
+ * - node is set to node id of the next populated region except for the
+ * trailing hole where last
