linux-kernel - [PATCH] SQUASHME: Fixes to e820 handling of pmem

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Message-ID: <551BFFD2.20608@plexistor.com>
Date:	Wed, 01 Apr 2015 17:25:22 +0300
From:	Boaz Harrosh <boaz@...xistor.com>
To:	Christoph Hellwig <hch@....de>, linux-nvdimm@...1.01.org,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	x86@...nel.org, axboe@...nel.dk
CC:	ross.zwisler@...ux.intel.com
Subject: [PATCH] SQUASHME: Fixes to e820 handling of pmem


Finally with these fixes I'm able to define memmap=!
regions in NUMA machines. Any combination cross or
not cross NUMA boundary.

And not only the memmap=! regions had problems also
the real type-12 NvDIMMs had the same NUMA problems.
Now it all works.

Also
I have kept the "don't merge PRAM" regions for ease
of emulated NUMA setups.

Also I have reverted the change Ch did to
e820_mark_nosave_regions. From comment above the function
and if I'm reading register_nosave_region() correctly,
We certainly do not want the system to try and save any
pmem to swap or hibernate. (Actually it will be the
opposite right). Can we actually define swap on a /dev/pmemX ? ;-)

Signed-off-by: Boaz Harrosh <boaz@...xistor.com>
---
 Documentation/kernel-parameters.txt |  6 ++++++
 arch/x86/kernel/e820.c              | 20 +++++++++-----------
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index bfcb1a6..c87122d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1965,6 +1965,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			         or
 			         memmap=0x10000$0x18690000
 
+	memmap=nn[KMG]!ss[KMG]
+			[KNL,X86] Mark specific memory as protected.
+			Region of memory to be used, from ss to ss+nn.
+			The memory region may be marked as e820 type 12 (0xc)
+			and is NVDIMM or ADR memory.
+
 	memory_corruption_check=0/1 [X86]
 			Some BIOSes seem to corrupt the first 64k of
 			memory when doing things like suspend/resume.
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index e26ca56..3572a22 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -346,7 +346,7 @@ int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map,
 		 * continue building up new bios map based on this
 		 * information
 		 */
-		if (current_type != last_type)	{
+		if (current_type != last_type || current_type == E820_PRAM) {
 			if (last_type != 0)	 {
 				new_bios[new_bios_entry].size =
 					change_point[chgidx]->addr - last_addr;
@@ -692,14 +692,8 @@ void __init e820_mark_nosave_regions(unsigned long limit_pfn)
 
 		pfn = PFN_DOWN(ei->addr + ei->size);
 
-		switch (ei->type) {
-		case E820_RAM:
-		case E820_PRAM:
-		case E820_RESERVED_KERN:
-			break;
-		default:
+		if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
 			register_nosave_region(PFN_UP(ei->addr), pfn);
-		}
 
 		if (pfn >= limit_pfn)
 			break;
@@ -880,6 +874,9 @@ static int __init parse_memmap_one(char *p)
 	} else if (*p == '$') {
 		start_at = memparse(p+1, &p);
 		e820_add_region(start_at, mem_size, E820_RESERVED);
+	} else if (*p == '!') {
+		start_at = memparse(p+1, &p);
+		e820_add_region(start_at, mem_size, E820_PRAM);
 	} else
 		e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
 
@@ -955,9 +952,10 @@ void __init e820_reserve_resources(void)
 		 * pci device BAR resource and insert them later in
 		 * pcibios_resource_survey()
 		 */
-		if (e820.map[i].type != E820_RESERVED || res->start < (1ULL<<20)) {
-			if (e820.map[i].type != E820_PRAM)
-				res->flags |= IORESOURCE_BUSY;
+		if (((e820.map[i].type != E820_RESERVED) &&
+		     (e820.map[i].type != E820_PRAM)) ||
+		     res->start < (1ULL<<20)) {
+			res->flags |= IORESOURCE_BUSY;
 			insert_resource(&iomem_resource, res);
 		}
 		res++;
-- 
1.9.3


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