FC10/i686 Compatibility Update (2.6.27.19-170.2.35.fc10.i686)

In the interests of portability I have added a FC10/i686 box to
my list of development platforms.  The hope is this will allow me
to keep current with upstream kernel API changes, and at the same
time ensure I don't accidentally break x86 support.  This patch
resolves all remaining issues observed under that environment.

1) SPL_AC_ZONE_STAT_ITEM_FIA autoconf check added.  As of 2.6.21
the kernel added a clean API for modules to get the global count
for free, inactive, and active pages.  The SPL attempts to detect
if this API is available and directly map spl_global_page_state()
to global_page_state().  If the full API is not available then
spl_global_page_state() is implemented as a thin layer to get
these values via get_zone_counts() if that symbol is available.

2) New kmem:vmem_size regression test added to validate correct
vmem_size() functionality.  The test case acquires the current
global vmem state, allocates from the vmem region, then verifies
the allocation is correctly reflected in the vmem_size() stats.

3) Change splat_kmem_cache_thread_test() to always use KMC_KMEM
based memory.  On x86 systems with limited virtual address space
failures resulted due to exhaustig the address space.  The tests
really need to problem exhausting all memory on the system thus
we need to use the physical address space.

4) Change kmem:slab_lock to cap it's memory usage at availrmem
instead of using the native linux nr_free_pages().  This provides
additional test coverage of the SPL Linux VM integration.

5) Change kmem:slab_overcommit to perform allocation of 256K
instead of 1M.  On x86 based systems it is not possible to create
a kmem backed slab with entires of that size.  To compensate for
this the number of allocations performed in increased by 4x.

6) Additional autoconf documentation for proposed upstream API
changes to make additional symbols available to modules.

7) Console error messages added when spl_kallsyms_lookup_name()
fails to locate an expected symbol.  This causes the module to fail
to load and we need to know exactly which symbol was not available.

1 files changed, 48 insertions, 5 deletions

diff --git a/config/spl-build.m4 b/config/spl-build.m4
index d0cf86d9a..1013e1f4c 100644
--- a/config/spl-build.m4
+++ b/config/spl-build.m4
@@ -752,7 +752,11 @@ AC_DEFUN([SPL_AC_KALLSYMS_LOOKUP_NAME], [
 ])
 
 dnl #
-dnl # Symbol only available in custom kernels
+dnl # Proposed API change,
+dnl # This symbol is not available in stock kernels.  You may build a
+dnl # custom kernel with the *-spl-export-symbols.patch which will export
+dnl # these symbols for use.  If your already rolling a custom kernel for
+dnl # your environment this is recommended.
 dnl #
 AC_DEFUN([SPL_AC_GET_VMALLOC_INFO], [
 	SPL_CHECK_SYMBOL_EXPORT(
@@ -764,7 +768,11 @@ AC_DEFUN([SPL_AC_GET_VMALLOC_INFO], [
 ])
 
 dnl #
-dnl # Symbol only available in custom kernels
+dnl # Proposed API change,
+dnl # This symbol is not available in stock kernels.  You may build a
+dnl # custom kernel with the *-spl-export-symbols.patch which will export
+dnl # these symbols for use.  If your already rolling a custom kernel for
+dnl # your environment this is recommended.
 dnl #
 AC_DEFUN([SPL_AC_FIRST_ONLINE_PGDAT], [
 	SPL_CHECK_SYMBOL_EXPORT(
@@ -776,7 +784,11 @@ AC_DEFUN([SPL_AC_FIRST_ONLINE_PGDAT], [
 ])
 
 dnl #
-dnl # Symbol only available in custom kernels
+dnl # Proposed API change,
+dnl # This symbol is not available in stock kernels.  You may build a
+dnl # custom kernel with the *-spl-export-symbols.patch which will export
+dnl # these symbols for use.  If your already rolling a custom kernel for
+dnl # your environment this is recommended.
 dnl #
 AC_DEFUN([SPL_AC_NEXT_ONLINE_PGDAT], [
 	SPL_CHECK_SYMBOL_EXPORT(
@@ -788,7 +800,11 @@ AC_DEFUN([SPL_AC_NEXT_ONLINE_PGDAT], [
 ])
 
 dnl #
-dnl # Symbol only available in custom kernels
+dnl # Proposed API change,
+dnl # This symbol is not available in stock kernels.  You may build a
+dnl # custom kernel with the *-spl-export-symbols.patch which will export
+dnl # these symbols for use.  If your already rolling a custom kernel for
+dnl # your environment this is recommended.
 dnl #
 AC_DEFUN([SPL_AC_NEXT_ZONE], [
 	SPL_CHECK_SYMBOL_EXPORT(
@@ -800,7 +816,11 @@ AC_DEFUN([SPL_AC_NEXT_ZONE], [
 ])
 
 dnl #
-dnl # Symbol only available in custom kernels
+dnl # Proposed API change,
+dnl # This symbol is not available in stock kernels.  You may build a
+dnl # custom kernel with the *-spl-export-symbols.patch which will export
+dnl # these symbols for use.  If your already rolling a custom kernel for
+dnl # your environment this is recommended.
 dnl #
 AC_DEFUN([SPL_AC_GET_ZONE_COUNTS], [
 	SPL_CHECK_SYMBOL_EXPORT(
@@ -810,3 +830,26 @@ AC_DEFUN([SPL_AC_GET_ZONE_COUNTS], [
 		[get_zone_counts() is available])],
 		[])
 ])
+
+dnl #
+dnl # 2.6.21 API change,
+dnl # Public global zone stats now include free/inactive/active page
+dnl # counts.  This replaced the priviate get_zone_counts() interface.
+dnl #
+AC_DEFUN([SPL_AC_ZONE_STAT_ITEM_FIA], [
+	AC_MSG_CHECKING([whether free/inactive/active page state is available])
+	SPL_LINUX_TRY_COMPILE([
+		#include <linux/mmzone.h>
+	],[
+		enum zone_stat_item i1, i2, i3;
+		i1 = NR_FREE_PAGES;
+		i2 = NR_INACTIVE;
+		i3 = NR_ACTIVE;
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_ZONE_STAT_ITEM_FIA, 1,
+		          [free/inactive/active page state is available])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])