kexec: Limit the crash memory ranges according to first kernel's memory limit.

PATCH Superseded Mahesh J Salgaonkar 2 participants 7 messages Aug 29, 2012 – Nov 30, 2012

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Mahesh J Salgaonkar

author

2012-08-29 08:27 UTC #0 lore raw

cover kexec: Limit the crash memory ranges according to first kernel's memory limit.

So far powerpc kernel never exported memory limit information which is reflected by mem= kernel cmdline option. Hence, kexec-tools always use to build ELF header for entire system RAM generating a dump bigger than the actual memory used by the first kernel.

The proposed upstream kernel patch at
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-August/100500.html
now exports memory limit information through /proc/device-tree file. The above patch is still in discussion.

This patch series now reads the memory limit information from device-tree file if present and limits the crash memory ranges accordingly.

Tested these patches on ppc32(ppc440) and ppc64 with a kernel patch by Suzuki.

Signed-off-by Mahesh Salgaonkar <[email protected]>

Tested-by Suzuki K. Poulose <[email protected]>

---

Mahesh Salgaonkar (2):
kexec: Respect memory limit while building crash memory ranges on ppc32.
kexec: Respect memory limit while building crash memory ranges on ppc64

 kexec/arch/ppc/crashdump-powerpc.c |   14 ++++++++---
 kexec/arch/ppc/crashdump-powerpc.h |    1 +
 kexec/arch/ppc/kexec-ppc.c         |   48 ++++++++++++++++++++++++++++++++++++
 kexec/arch/ppc64/crashdump-ppc64.c |   11 ++++++++
 kexec/arch/ppc64/crashdump-ppc64.h |    1 +
 kexec/arch/ppc64/kexec-ppc64.c     |   28 +++++++++++++++++++++
 6 files changed, 99 insertions(+), 4 deletions(-)

Signature · 7 lines

-Mahesh


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Mahesh J Salgaonkar

author

2012-08-29 08:27 UTC #1 lore raw

PATCH 1/2 kexec: Respect memory limit while building crash memory ranges on ppc32.

From: Mahesh Salgaonkar <[email protected]>

So far powerpc kernel never exported memory limit information which is reflected by mem= kernel cmdline option. Hence, kexec-tools always used to build ELF header for entire system RAM generating a dump bigger than the actual memory used by the first kernel.

This patch now reads the memory limit information from device-tree file and limits the crash memory ranges accordingly.

Suzuki tested this patch on ppc32(ppc440) with a kernel patch by Suzuki.

The proposed upstream kernel patch at
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-August/100500.html
now exports memory limit information through /proc/device-tree file.

Signed-off-by Mahesh Salgaonkar <[email protected]>

Tested-by Suzuki K. Poulose <[email protected]>

---
 kexec/arch/ppc/crashdump-powerpc.c |   14 ++++++++---
 kexec/arch/ppc/crashdump-powerpc.h |    1 +
 kexec/arch/ppc/kexec-ppc.c         |   48 ++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 3 deletions(-)

kexec/arch/ppc/crashdump-powerpc.c +11 -3

index 4c8c75d..7313660 100644
@@ -132,8 +132,9 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges)
 				goto err;
 			}
 			n = read_memory_region_limits(fd, &start, &end);
+			/* We are done with fd, close it. */
+			close(fd);
 			if (n != 0) {
-				close(fd);
 				closedir(dmem);
 				closedir(dir);
 				goto err;

@@ -153,8 +154,16 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges)
 			cstart = crash_base;
 			cend = crash_base + crash_size;
 			/*
-			 * Exclude the region that lies within crashkernel
+			 * Exclude the region that lies within crashkernel.
+			 * If memory limit is set then exclude memory region
+			 * above it.
 			 */
+			if (memory_limit) {
+				if (start > memory_limit)
+					continue;
+				if (end > memory_limit)
+					end = memory_limit;
+			}
 			if (cstart < end && cend > start) {
 				if (start < cstart && end > cend) {
 					crash_memory_range[memory_ranges].start

@@ -195,7 +204,6 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges)
 					= RANGE_RAM;
 				memory_ranges++;
 			}
-			close(fd);
 		}
 		closedir(dmem);
 	}

kexec/arch/ppc/crashdump-powerpc.h +1 -0

index a377146..84a73aa 100644
@@ -42,5 +42,6 @@ extern unsigned long long crash_base;
 extern unsigned long long crash_size;
 extern unsigned int rtas_base;
 extern unsigned int rtas_size;
+extern uint64_t memory_limit;
 
 #endif /* CRASHDUMP_POWERPC_H */

kexec/arch/ppc/kexec-ppc.c +48 -0

66 lines not on this page · raw message

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Mahesh J Salgaonkar

author

2012-08-29 08:27 UTC #2 lore raw

PATCH 2/2 kexec: Respect memory limit while building crash memory ranges on ppc64

In reply to Mahesh J Salgaonkar

From: Mahesh Salgaonkar <[email protected]>

Fix it on ppc64 also. This patch now reads the memory limit information from device-tree file and limits the crash memory ranges accordingly.

Tested this patch on ppc64 with a kernel patch by Suzuki.

Signed-off-by Mahesh Salgaonkar <[email protected]>

---
 kexec/arch/ppc64/crashdump-ppc64.c |   11 ++++++++++-
 kexec/arch/ppc64/crashdump-ppc64.h |    1 +
 kexec/arch/ppc64/kexec-ppc64.c     |   28 ++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletions(-)

kexec/arch/ppc64/crashdump-ppc64.c +10 -1

index 30ef443..690b1f7 100644
@@ -84,10 +84,19 @@ static unsigned long long cstart, cend;
 static int memory_ranges;
 
 /*
- * Exclude the region that lies within crashkernel
+ * Exclude the region that lies within crashkernel and above the memory
+ * limit which is reflected by mem= kernel option.
  */
 static void exclude_crash_region(uint64_t start, uint64_t end)
 {
+	/* If memory_limit is set then exclude the memory region above it. */
+	if (memory_limit) {
+		if (start > memory_limit)
+			return;
+		if (end > memory_limit)
+			end = memory_limit;
+	}
+
 	if (cstart < end && cend > start) {
 		if (start < cstart && end > cend) {
 			crash_memory_range[memory_ranges].start = start;

kexec/arch/ppc64/crashdump-ppc64.h +1 -0

index be02213..739c61f 100644
@@ -27,6 +27,7 @@ void add_usable_mem_rgns(unsigned long long base, unsigned long long size);
 
 extern uint64_t crash_base;
 extern uint64_t crash_size;
+extern uint64_t memory_limit;
 extern unsigned int rtas_base;
 extern unsigned int rtas_size;

kexec/arch/ppc64/kexec-ppc64.c +28 -0

index 2f12907..189d48e 100644
@@ -39,6 +39,7 @@ static struct memory_range *memory_range = NULL;
 static struct memory_range *base_memory_range = NULL;
 static uint64_t rmo_top;
 uint64_t memory_max = 0;
+uint64_t memory_limit = 0;
 static int nr_memory_ranges, nr_exclude_ranges;
 uint64_t crash_base, crash_size;
 unsigned int rtas_base, rtas_size;

@@ -408,6 +409,33 @@ static int get_devtree_details(unsigned long kexec_flags)
 				add_usable_mem_rgns(0, crash_base + crash_size);
 				reserve(KDUMP_BACKUP_LIMIT, crash_base-KDUMP_BACKUP_LIMIT);
 			}
+			/*
+			 * Read the first kernel's memory limit.
+			 * If the first kernel is booted with mem= option then
+			 * it would export "linux,memory-limit" file
+			 * reflecting value for the same.
+			 */
+			memset(fname, 0, sizeof(fname));
+			strcpy(fname, device_tree);
+			strcat(fname, dentry->d_name);
+			strcat(fname, "/linux,memory-limit");
+			if ((file = fopen(fname, "r")) == NULL) {
+				if (errno != ENOENT) {
+					perror(fname);
+					goto error_opencdir;
+                                }
+				errno = 0;
+				/*
+				 * File not present.
+				 * fall through. On older kernel this file
+				 * is not present.
+				 */
+			}
+			else if (fread(&memory_limit, sizeof(uint64_t), 1, file)
+								!= 1) {
+				perror(fname);
+				goto error_openfile;
+			}
 
 			memset(fname, 0, sizeof(fname));
 			strcpy(fname, device_tree);

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Mahesh Jagannath Salgaonkar

author

2012-10-24 03:22 UTC #3 lore raw

In reply to Mahesh J Salgaonkar

Quoted 9 lines · Mahesh J Salgaonkar

So far powerpc kernel never exported memory limit information which is reflected by mem= kernel cmdline option. Hence, kexec-tools always use to build ELF header for entire system RAM generating a dump bigger than the actual memory used by the first kernel.
The proposed upstream kernel patch at
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-August/100500.html
now exports memory limit information through /proc/device-tree file. The above patch is still in discussion.

The above mentioned kernel patches are now upstream. Below are commit ids:
4bc77a5e - powerpc: Export memory limit via device tree a84fcd468 - powerpc: Change memory_limit from phys_addr_t to unsigned long long

Quoted 16 lines

This patch series now reads the memory limit information from device-tree file if present and limits the crash memory ranges accordingly.
Tested these patches on ppc32(ppc440) and ppc64 with a kernel patch by Suzuki.
Signed-off-by Mahesh Salgaonkar <[email protected]>
Tested-by Suzuki K. Poulose <[email protected]>
---
Mahesh Salgaonkar (2):
kexec: Respect memory limit while building crash memory ranges on ppc32.
kexec: Respect memory limit while building crash memory ranges on ppc64

Quoted 8 lines

 kexec/arch/ppc/crashdump-powerpc.c |   14 ++++++++---
 kexec/arch/ppc/crashdump-powerpc.h |    1 +
 kexec/arch/ppc/kexec-ppc.c         |   48 ++++++++++++++++++++++++++++++++++++
 kexec/arch/ppc64/crashdump-ppc64.c |   11 ++++++++
 kexec/arch/ppc64/crashdump-ppc64.h |    1 +
 kexec/arch/ppc64/kexec-ppc64.c     |   28 +++++++++++++++++++++
 6 files changed, 99 insertions(+), 4 deletions(-)

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Baoquan

2012-11-13 03:38 UTC #4 lore raw

Hi,

I have tested ppc64 part of this patchset, and it works. Do you plan to merge this patchset?

Quoted 39 lines · Mahesh Jagannath Salgaonkar

Quoted 9 lines · Mahesh J Salgaonkar
So far powerpc kernel never exported memory limit information which is reflected by mem= kernel cmdline option. Hence, kexec-tools always use to build ELF header for entire system RAM generating a dump bigger than the actual memory used by the first kernel.
The proposed upstream kernel patch at
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-August/100500.html
now exports memory limit information through /proc/device-tree file. The above patch is still in discussion.
The above mentioned kernel patches are now upstream. Below are commit ids:
4bc77a5e - powerpc: Export memory limit via device tree a84fcd468 - powerpc: Change memory_limit from phys_addr_t to unsigned long long
Quoted 15 lines
This patch series now reads the memory limit information from device-tree file if present and limits the crash memory ranges accordingly.
Tested these patches on ppc32(ppc440) and ppc64 with a kernel patch by Suzuki.
Signed-off-by Mahesh Salgaonkar<[email protected]>
Tested-by Suzuki K. Poulose<[email protected]>
---
Mahesh Salgaonkar (2):
kexec: Respect memory limit while building crash memory ranges on ppc32.
kexec: Respect memory limit while building crash memory ranges on ppc64
Quoted 8 lines
  kexec/arch/ppc/crashdump-powerpc.c |   14 ++++++++---
  kexec/arch/ppc/crashdump-powerpc.h |    1 +
  kexec/arch/ppc/kexec-ppc.c         |   48 ++++++++++++++++++++++++++++++++++++
  kexec/arch/ppc64/crashdump-ppc64.c |   11 ++++++++
  kexec/arch/ppc64/crashdump-ppc64.h |    1 +
  kexec/arch/ppc64/kexec-ppc64.c     |   28 +++++++++++++++++++++
  6 files changed, 99 insertions(+), 4 deletions(-)

Quoted 4 lines

_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec

_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec

Baoquan

2012-11-14 09:33 UTC #5 lore raw

Quoted 5 lines · Baoquan

Hi,
I have tested ppc64 part of this patchset, and it works. Do you plan to merge this patchset?

Sorry, above question should go to Simon.

Quoted 49 lines · Mahesh Jagannath Salgaonkar

Quoted 42 lines · Mahesh J Salgaonkar
Quoted 9 lines
So far powerpc kernel never exported memory limit information which is reflected by mem= kernel cmdline option. Hence, kexec-tools always use to build ELF header for entire system RAM generating a dump bigger than the actual memory used by the first kernel.
The proposed upstream kernel patch at
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-August/100500.html
now exports memory limit information through /proc/device-tree file. The above patch is still in discussion.
The above mentioned kernel patches are now upstream. Below are commit ids:
4bc77a5e - powerpc: Export memory limit via device tree a84fcd468 - powerpc: Change memory_limit from phys_addr_t to unsigned long long
Quoted 17 lines
This patch series now reads the memory limit information from device-tree file if present and limits the crash memory ranges accordingly.
Tested these patches on ppc32(ppc440) and ppc64 with a kernel patch by Suzuki.
Signed-off-by Mahesh Salgaonkar<[email protected]>
Tested-by Suzuki K. Poulose<[email protected]>
---
Mahesh Salgaonkar (2):
kexec: Respect memory limit while building crash memory
ranges on ppc32.
kexec: Respect memory limit while building crash memory
ranges on ppc64
Quoted 9 lines
  kexec/arch/ppc/crashdump-powerpc.c |   14 ++++++++---
  kexec/arch/ppc/crashdump-powerpc.h |    1 +
  kexec/arch/ppc/kexec-ppc.c         |   48 
++++++++++++++++++++++++++++++++++++
  kexec/arch/ppc64/crashdump-ppc64.c |   11 ++++++++
  kexec/arch/ppc64/crashdump-ppc64.h |    1 +
  kexec/arch/ppc64/kexec-ppc64.c     |   28 +++++++++++++++++++++
  6 files changed, 99 insertions(+), 4 deletions(-)
Quoted 4 lines
_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec

Quoted 4 lines

_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec

_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec

Mahesh Jagannath Salgaonkar

author

2012-11-30 03:08 UTC #6 lore raw

In reply to Mahesh Jagannath Salgaonkar

Quoted 11 lines · Mahesh Jagannath Salgaonkar

Quoted 9 lines · Mahesh J Salgaonkar
So far powerpc kernel never exported memory limit information which is reflected by mem= kernel cmdline option. Hence, kexec-tools always use to build ELF header for entire system RAM generating a dump bigger than the actual memory used by the first kernel.
The proposed upstream kernel patch at
https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-August/100500.html
now exports memory limit information through /proc/device-tree file. The above patch is still in discussion.

Quoted 4 lines

The above mentioned kernel patches are now upstream. Below are commit ids:
4bc77a5e - powerpc: Export memory limit via device tree a84fcd468 - powerpc: Change memory_limit from phys_addr_t to unsigned long long

Hi Simon,

Did you get chance to review these patchset? The kernel patches are already in upstream.

Thanks,
-Mahesh.

Quoted 27 lines

Quoted 17 lines
This patch series now reads the memory limit information from device-tree file if present and limits the crash memory ranges accordingly.
Tested these patches on ppc32(ppc440) and ppc64 with a kernel patch by Suzuki.
Signed-off-by Mahesh Salgaonkar <[email protected]>
Tested-by Suzuki K. Poulose <[email protected]>
---
Mahesh Salgaonkar (2):
kexec: Respect memory limit while building crash memory ranges on ppc32.
kexec: Respect memory limit while building crash memory ranges on ppc64
Quoted 8 lines
 kexec/arch/ppc/crashdump-powerpc.c |   14 ++++++++---
 kexec/arch/ppc/crashdump-powerpc.h |    1 +
 kexec/arch/ppc/kexec-ppc.c         |   48 ++++++++++++++++++++++++++++++++++++
 kexec/arch/ppc64/crashdump-ppc64.c |   11 ++++++++
 kexec/arch/ppc64/crashdump-ppc64.h |    1 +
 kexec/arch/ppc64/kexec-ppc64.c     |   28 +++++++++++++++++++++
 6 files changed, 99 insertions(+), 4 deletions(-)

Quoted 5 lines

_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec

_______________________________________________
kexec mailing list
[email protected]
http://lists.infradead.org/mailman/listinfo/kexec