| Message ID | 20210427121354.3620-1-isaev@synopsys.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] ARC: Use max_high_pfn as a HIGHMEM zone border | expand |
On 4/27/21 5:13 AM, Vladimir Isaev wrote: > Commit 4af22ded0ecf ("arc: fix memory initialization for systems > with two memory banks") fixed highmem, but for the PAE case it causes > bug messages: > > BUG: Bad page state in process swapper pfn:80000 > page:(ptrval) refcount:0 mapcount:1 mapping:00000000 index:0x0 pfn:0x80000 > flags: 0x0() > raw: 00000000 00000100 00000122 00000000 00000000 00000000 00000000 00000000 > raw: 00000000 > page dumped because: nonzero mapcount > Modules linked in: > CPU: 0 PID: 0 Comm: swapper Not tainted 5.12.0-rc5-00003-g1e43c377a79f #1 > > Stack Trace: > arc_unwind_core+0xe8/0x118 > Disabling lock debugging due to kernel taint > > This is because the fix expects highmem to be always less than > lowmem and uses min_low_pfn as an upper zone border for highmem. > > max_high_pfn should be ok for both highmem and highmem+PAE cases. > > Signed-off-by: Vladimir Isaev <isaev@synopsys.com> > Cc: Mike Rapoport <rppt@linux.ibm.com> > Cc: Vineet Gupta <vgupta@synopsys.com> Applied to for-curr. Thx, -Vineet > --- > Changes for v2: > - Revised commit message and added comment to code > --- > arch/arc/mm/init.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c > index ce07e697916c..1bcc6985b9a0 100644 > --- a/arch/arc/mm/init.c > +++ b/arch/arc/mm/init.c > @@ -157,7 +157,16 @@ void __init setup_arch_memory(void) > min_high_pfn = PFN_DOWN(high_mem_start); > max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz); > > - max_zone_pfn[ZONE_HIGHMEM] = min_low_pfn; > + /* > + * max_high_pfn should be ok here for both HIGHMEM and HIGHMEM+PAE. > + * For HIGHMEM without PAE max_high_pfn should be less than > + * min_low_pfn to guarantee that these two regions don't overlap. > + * For PAE case highmem is greater than lowmem, so it is natural > + * to use max_high_pfn. > + * > + * In both cases, holes should be handled by pfn_valid(). > + */ > + max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn; > > high_memory = (void *)(min_high_pfn << PAGE_SHIFT); >
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c index ce07e697916c..1bcc6985b9a0 100644 --- a/arch/arc/mm/init.c +++ b/arch/arc/mm/init.c @@ -157,7 +157,16 @@ void __init setup_arch_memory(void) min_high_pfn = PFN_DOWN(high_mem_start); max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz); - max_zone_pfn[ZONE_HIGHMEM] = min_low_pfn; + /* + * max_high_pfn should be ok here for both HIGHMEM and HIGHMEM+PAE. + * For HIGHMEM without PAE max_high_pfn should be less than + * min_low_pfn to guarantee that these two regions don't overlap. + * For PAE case highmem is greater than lowmem, so it is natural + * to use max_high_pfn. + * + * In both cases, holes should be handled by pfn_valid(). + */ + max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn; high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
Commit 4af22ded0ecf ("arc: fix memory initialization for systems with two memory banks") fixed highmem, but for the PAE case it causes bug messages: BUG: Bad page state in process swapper pfn:80000 page:(ptrval) refcount:0 mapcount:1 mapping:00000000 index:0x0 pfn:0x80000 flags: 0x0() raw: 00000000 00000100 00000122 00000000 00000000 00000000 00000000 00000000 raw: 00000000 page dumped because: nonzero mapcount Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.12.0-rc5-00003-g1e43c377a79f #1 Stack Trace: arc_unwind_core+0xe8/0x118 Disabling lock debugging due to kernel taint This is because the fix expects highmem to be always less than lowmem and uses min_low_pfn as an upper zone border for highmem. max_high_pfn should be ok for both highmem and highmem+PAE cases. Signed-off-by: Vladimir Isaev <isaev@synopsys.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> --- Changes for v2: - Revised commit message and added comment to code --- arch/arc/mm/init.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)