Carsten Otte 9723198c21 #ifdef very expensive debug check in page fault path ... This patch puts #ifdef CONFIG_DEBUG_VM around a check in vm_normal_page that verifies that a pfn is valid. This patch increases performance of the page fault microbenchmark in lmbench by 13% and overall dbench performance by 7% on s390x. pfn_valid() is an expensive operation on s390 that needs a high double digit amount of CPU cycles. Nick Piggin suggested that pfn_valid() involves an array lookup on systems with sparsemem, and therefore is an expensive operation there too. The check looks like a clear debug thing to me, it should never trigger on regular kernels. And if a pte is created for an invalid pfn, we'll find out once the memory gets accessed later on anyway. Please consider inclusion of this patch into mm. Signed-off-by: Carsten Otte <cotte@de.ibm.com> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2008-01-17 15:38:59 -08:00
..
allocpercpu.c	Slab allocators: Replace explicit zeroing with __GFP_ZERO	2007-07-17 10:23:02 -07:00
backing-dev.c	mm/backing-dev.c: fix percpu_counter_destroy call bug in bdi_init	2007-12-05 09:21:18 -08:00
bootmem.c	[PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols	2006-12-07 08:39:44 -08:00
bounce.c	block: Initial support for data-less (or empty) barrier support	2007-10-16 11:03:56 +02:00
fadvise.c	[PATCH] mm: change uses of f_{dentry,vfsmnt} to use f_path	2006-12-08 08:28:43 -08:00
filemap_xip.c	xip: fix get_zeroed_page with __GFP_HIGHMEM	2008-01-08 16:10:36 -08:00
filemap.c	Do dirty page accounting when removing a page from the page cache	2007-12-19 14:05:13 -08:00
fremap.c	remap_file_pages: kernel-doc corrections	2007-10-17 08:43:07 -07:00
highmem.c	Create the ZONE_MOVABLE zone	2007-07-17 10:22:59 -07:00
hugetlb.c	hugetlbfs: fix quota leak	2008-01-14 08:52:23 -08:00
internal.h	Breakout page_order() to internal.h to avoid special knowledge of the buddy allocator	2007-10-16 09:43:01 -07:00
Kconfig	sparsemem: make SPARSEMEM_VMEMMAP selectable	2007-12-17 19:28:16 -08:00
madvise.c	speed up madvise_need_mmap_write() usage	2007-07-16 09:05:36 -07:00
Makefile	memory unplug: page isolation	2007-10-16 09:43:02 -07:00
memory_hotplug.c	Add IORESOUCE_BUSY flag for System RAM	2007-11-14 18:45:39 -08:00
memory.c	#ifdef very expensive debug check in page fault path	2008-01-17 15:38:59 -08:00
mempolicy.c	Migration: find correct vma in new_vma_page()	2007-11-14 18:45:38 -08:00
mempool.c	spelling fixes: mm/	2007-10-20 01:27:18 +02:00
migrate.c	Typo fixes retrun -> return	2007-10-20 02:13:26 +02:00
mincore.c	[PATCH] mincore: vma crossing fix	2007-02-15 09:57:03 -08:00
mlock.c	do not limit locked memory when RLIMIT_MEMLOCK is RLIM_INFINITY	2007-07-16 09:05:37 -07:00
mmap.c	VM/Security: add security hook to do_brk	2007-12-05 09:21:21 -08:00
mmzone.c	[PATCH] remove EXPORT_UNUSED_SYMBOL'ed symbols	2006-12-07 08:39:44 -08:00
mprotect.c	fix mprotect vma_wants_writenotify prot	2007-10-23 08:32:06 -07:00
mremap.c	sparse pointer use of zero as null	2007-10-18 14:37:31 -07:00
msync.c	Detach sched.h from mm.h	2007-05-21 09:18:19 -07:00
nommu.c	Security: round mmap hint address above mmap_min_addr	2007-12-06 00:25:10 +11:00
oom_kill.c	oom_kill bug	2007-10-20 15:04:06 -07:00
page_alloc.c	mm: fix section mismatch warning in page_alloc.c	2008-01-17 15:38:58 -08:00
page_io.c	Drop 'size' argument from bio_endio and bi_end_io	2007-10-10 09:25:57 +02:00
page_isolation.c	memory hotremove: unset migrate type "ISOLATE" after removal	2007-11-14 18:45:38 -08:00
page-writeback.c	Revert "writeback: introduce writeback_control.more_io to indicate more io"	2008-01-14 21:21:29 -08:00
pdflush.c	Freezer: make kernel threads nonfreezable by default	2007-07-17 10:23:02 -07:00
prio_tree.c	spelling fixes: mm/	2007-10-20 01:27:18 +02:00
quicklist.c	quicklists: Only consider memory that can be used with GFP_KERNEL	2008-01-14 08:52:22 -08:00
readahead.c	mm: bdi init hooks	2007-10-17 08:42:45 -07:00
rmap.c	[S390] Optimize storage key handling for anonymous pages	2007-11-20 11:13:46 +01:00
shmem_acl.c	[PATCH] Fix typos in mm/shmem_acl.c	2006-10-11 11:14:23 -07:00
shmem.c	tmpfs: restore missing clear_highpage	2007-11-28 11:04:28 -08:00
slab.c	Unify /proc/slabinfo configuration	2008-01-02 13:04:48 -08:00
slob.c	Avoid double memclear() in SLOB/SLUB	2007-12-09 10:17:52 -08:00
slub.c	Unify /proc/slabinfo configuration	2008-01-02 13:04:48 -08:00
sparse-vmemmap.c	memory hotplug fix: fix section mismatch in vmammap_allock_block()	2007-11-29 09:24:54 -08:00
sparse.c	mm/sparse.c: improve the error handling for sparse_add_one_section()	2007-12-17 19:28:16 -08:00
swap_state.c	mm: clarify __add_to_swap_cache locking	2007-10-16 09:42:53 -07:00
swap.c	spelling fixes: mm/	2007-10-20 01:27:18 +02:00
swapfile.c	Replace CONFIG_SOFTWARE_SUSPEND with CONFIG_HIBERNATION	2007-07-29 16:45:38 -07:00
thrash.c	Bug in mm/thrash.c function grab_swap_token()	2007-05-11 08:29:32 -07:00
tiny-shmem.c	r/o bind mounts: filesystem helpers for custom 'struct file's	2007-10-17 08:43:04 -07:00
truncate.c	Drop some headers from mm.h	2007-10-17 08:42:55 -07:00
util.c	fix mm/util.c:krealloc()	2007-11-14 18:45:41 -08:00
vmalloc.c	spelling fixes: mm/	2007-10-20 01:27:18 +02:00
vmscan.c	spelling fixes: mm/	2007-10-20 01:27:18 +02:00
vmstat.c	vmstat: fix section mismatch warning	2007-11-14 18:45:42 -08:00