kernel_optimize_test/kernel
Wu Fengguang 37b99dd537 resource: Fix generic page_is_ram() for partial RAM pages
The System RAM walk shall skip partial RAM pages and avoid calling
func() on them. So that page_is_ram() return 0 for a partial RAM page.

In particular, it shall not call func() with len=0.
This fixes a boot time bug reported by Sachin and root caused by Thomas:

> >>> WARNING: at arch/x86/mm/ioremap.c:111 __ioremap_caller+0x169/0x2f1()
> >>> Hardware name: BladeCenter LS21 -[79716AA]-
> >>> Modules linked in:
> >>> Pid: 0, comm: swapper Not tainted 2.6.33-git6-autotest #1
> >>> Call Trace:
> >>> [<ffffffff81047cff>] ? __ioremap_caller+0x169/0x2f1
> >>> [<ffffffff81063b7d>] warn_slowpath_common+0x77/0xa4
> >>> [<ffffffff81063bb9>] warn_slowpath_null+0xf/0x11
> >>> [<ffffffff81047cff>] __ioremap_caller+0x169/0x2f1
> >>> [<ffffffff813747a3>] ? acpi_os_map_memory+0x12/0x1b
> >>> [<ffffffff81047f10>] ioremap_nocache+0x12/0x14
> >>> [<ffffffff813747a3>] acpi_os_map_memory+0x12/0x1b
> >>> [<ffffffff81282fa0>] acpi_tb_verify_table+0x29/0x5b
> >>> [<ffffffff812827f0>] acpi_load_tables+0x39/0x15a
> >>> [<ffffffff8191c8f8>] acpi_early_init+0x60/0xf5
> >>> [<ffffffff818f2cad>] start_kernel+0x397/0x3a7
> >>> [<ffffffff818f2295>] x86_64_start_reservations+0xa5/0xa9
> >>> [<ffffffff818f237a>] x86_64_start_kernel+0xe1/0xe8
> >>> ---[ end trace 4eaa2a86a8e2da22 ]---
> >>> ioremap reserve_memtype failed -22

The return code is -EINVAL, so it failed in the is_ram check, which is
not too surprising

> BIOS-provided physical RAM map:
>  BIOS-e820: 0000000000000000 - 000000000009c000 (usable)
>  BIOS-e820: 000000000009c000 - 00000000000a0000 (reserved)
>  BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
>  BIOS-e820: 0000000000100000 - 00000000cffa3900 (usable)
>  BIOS-e820: 00000000cffa3900 - 00000000cffa7400 (ACPI data)

The ACPI data is not starting on a page boundary and neither does the
usable RAM area end on a page boundary. Very useful !

> ACPI: DSDT 00000000cffa3900 036CE (v01 IBM    SERLEWIS 00001000 INTL 20060912)

ACPI is trying to map DSDT at cffa3900, which results in a check
vs. cffa3000 which is the relevant page boundary. The generic is_ram
check correctly identifies that as RAM because it's in the usable
resource area. The old e820 based is_ram check does not take
overlapping resource areas into account. That's why it works.

CC: Sachin Sant <sachinp@in.ibm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
LKML-Reference: <20100301135551.GA9998@localhost>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-03-01 10:18:32 -08:00
..
gcov
irq
power
time Export the symbol of getboottime and mmonotonic_to_bootbased 2010-02-09 19:20:15 +02:00
trace tracing/kprobes: Fix probe parsing 2010-02-14 09:43:58 +01:00
.gitignore
acct.c
async.c
audit_tree.c
audit_watch.c
audit.c
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c cgroups: fix to return errno in a failure path 2010-02-02 18:11:22 -08:00
compat.c
configs.c
cpu.c sched: Correct printk whitespace in warning from cpu down task check 2010-01-28 06:59:55 +01:00
cpuset.c
cred-internals.h
cred.c kernel/cred.c: use kmem_cache_free 2010-02-03 10:21:57 +11:00
delayacct.c
dma.c
exec_domain.c
exit.c
extable.c
fork.c sched: Fix fork vs hotplug vs cpuset namespaces 2010-01-21 23:25:31 +01:00
freezer.c
futex_compat.c
futex.c futex: Handle futex value corruption gracefully 2010-02-03 15:13:22 +01:00
groups.c
hrtimer.c
hung_task.c
hw_breakpoint.c perf: Make bp_len type to u64 generic across the arch 2010-02-04 01:07:12 +01:00
itimer.c
kallsyms.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c Merge git://git.infradead.org/~dwmw2/mtd-2.6.33 2010-01-24 10:31:34 -08:00
kfifo.c kfifo: Don't use integer as NULL pointer 2010-02-16 15:11:08 -08:00
kgdb.c Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-04 16:07:41 -08:00
kmod.c
kprobes.c
ksysfs.c
kthread.c
latencytop.c
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
lockdep.c lockdep: Fix check_usage_backwards() error message 2010-01-27 08:34:02 +01:00
Makefile
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
ns_cgroup.c
nsproxy.c
panic.c
params.c
perf_event.c perf: Make bp_len type to u64 generic across the arch 2010-02-04 01:07:12 +01:00
pid_namespace.c
pid.c
pm_qos_params.c
posix-cpu-timers.c
posix-timers.c
printk.c Merge git://git.infradead.org/~dwmw2/mtd-2.6.33 2010-01-24 10:31:34 -08:00
profile.c
ptrace.c
rcupdate.c
rcutiny.c
rcutorture.c
rcutree_plugin.h
rcutree_trace.c
rcutree.c
rcutree.h
relay.c
res_counter.c
resource.c resource: Fix generic page_is_ram() for partial RAM pages 2010-03-01 10:18:32 -08:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
sched_clock.c
sched_cpupri.c
sched_cpupri.h
sched_debug.c
sched_fair.c sched: Fix vmark regression on big machines 2010-01-21 13:39:03 +01:00
sched_features.h
sched_idletask.c
sched_rt.c
sched_stats.h
sched.c sched: Fix fork vs hotplug vs cpuset namespaces 2010-01-21 23:25:31 +01:00
seccomp.c
semaphore.c
signal.c
slow-work-debugfs.c
slow-work.c
slow-work.h
smp.c
softirq.c hrtimer, softirq: Fix hrtimer->softirq trampoline 2010-02-03 18:17:40 +01:00
softlockup.c softlockup: Add sched_clock_tick() to avoid kernel warning on kgdb resume 2010-02-01 08:22:32 +01:00
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c
sysctl_binary.c
sysctl_check.c
sysctl.c
taskstats.c
test_kprobes.c
time.c
timeconst.pl
timer.c perf: Fix perf_event_do_pending() fallback callsite 2010-01-21 13:40:39 +01:00
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
wait.c
workqueue.c