Looks like these patches are lost in the mix. Resending with following note.
Dave, This requires your Ack as it touches sparc. Peter is waiting
for your Ack to queue it. Here is our previous discussion.
http://marc.info/?t=147500486300001&r=1&w=2
These patches limit the static allocations for lockdep data structures
used for debugging locking correctness. For sparc, all the kernel's code,
data, and bss, must have locked translations in the TLB so that we don't
get TLB misses on kernel code and data. Current sparc chips have 8 TLB
entries available that may be locked down, and with a 4mb page size,
this gives a maximum of 32MB. With PROVE_LOCKING we could go over this
limit and cause system boot-up problems. These patches limit the static
allocations so that everything fits in current required size limit.
patch 1 : Adds new config parameter CONFIG_PROVE_LOCKING_SMALL
Patch 2 : Adjusts the sizes based on the new config parameter
v2-> v3:
Some more comments from Sam Ravnborg and Peter Zijlstra.
Defined PROVE_LOCKING_SMALL as invisible and moved the selection to
arch/sparc/Kconfig.
v1-> v2:
As suggested by Peter Zijlstra, keeping the default as is.
Introduced new config variable CONFIG_PROVE_LOCKING_SMALL
to handle sparc specific case.
v0:
Initial revision.
Babu Moger (2):
config: Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL
for sparc
lockdep: Limit static allocations if PROVE_LOCKING_SMALL is defined
arch/sparc/Kconfig | 1 +
kernel/locking/lockdep_internals.h | 20 +++++++++++++++++---
lib/Kconfig.debug | 3 +++
3 files changed, 21 insertions(+), 3 deletions(-)
Reduce the size of data structure for lockdep entries by half if
PROVE_LOCKING_SMALL if defined. This is used only for sparc.
Signed-off-by: Babu Moger <[email protected]>
Acked-by: Sam Ravnborg <[email protected]>
---
kernel/locking/lockdep_internals.h | 20 +++++++++++++++++---
1 files changed, 17 insertions(+), 3 deletions(-)
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 51c4b24..c2b8849 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -46,6 +46,14 @@ enum {
(LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
/*
+ * CONFIG_PROVE_LOCKING_SMALL is defined for sparc. Sparc requires .text,
+ * .data and .bss to fit in required 32MB limit for the kernel. With
+ * PROVE_LOCKING we could go over this limit and cause system boot-up problems.
+ * So, reduce the static allocations for lockdeps related structures so that
+ * everything fits in current required size limit.
+ */
+#ifdef CONFIG_PROVE_LOCKING_SMALL
+/*
* MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
* we track.
*
@@ -54,18 +62,24 @@ enum {
* table (if it's not there yet), and we check it for lock order
* conflicts and deadlocks.
*/
+#define MAX_LOCKDEP_ENTRIES 16384UL
+#define MAX_LOCKDEP_CHAINS_BITS 15
+#define MAX_STACK_TRACE_ENTRIES 262144UL
+#else
#define MAX_LOCKDEP_ENTRIES 32768UL
#define MAX_LOCKDEP_CHAINS_BITS 16
-#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
-
-#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
/*
* Stack-trace: tightly packed array of stack backtrace
* addresses. Protected by the hash_lock.
*/
#define MAX_STACK_TRACE_ENTRIES 524288UL
+#endif
+
+#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
+
+#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
extern struct list_head all_lock_classes;
extern struct lock_chain lock_chains[];
--
1.7.1
This new config parameter limits the space used for "Lock debugging:
prove locking correctness" by about 4MB. The current sparc systems have
the limitation of 32MB size for kernel size including .text, .data and
.bss sections. With PROVE_LOCKING feature, the kernel size could grow
beyond this limit and causing system boot-up issues. With this option,
kernel limits the size of the entries of lock_chains, stack_trace etc.,
so that kernel fits in required size limit. This is not visible to user
and only used for sparc.
Signed-off-by: Babu Moger <[email protected]>
Acked-by: Sam Ravnborg <[email protected]>
---
arch/sparc/Kconfig | 1 +
lib/Kconfig.debug | 3 +++
2 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index b23c76b..a85e51d 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -43,6 +43,7 @@ config SPARC
select ARCH_HAS_SG_CHAIN
select CPU_NO_EFFICIENT_FFS
select HAVE_ARCH_HARDENED_USERCOPY
+ select PROVE_LOCKING_SMALL if PROVE_LOCKING
config SPARC32
def_bool !64BIT
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index b01e547..a6c8db1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1085,6 +1085,9 @@ config PROVE_LOCKING
For more details, see Documentation/locking/lockdep-design.txt.
+config PROVE_LOCKING_SMALL
+ bool
+
config LOCKDEP
bool
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
--
1.7.1