Olaf Hering 997c136f51 fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pages ... The balloon driver in a Xen guest frees guest pages and marks them as mmio. When the kernel crashes and the crash kernel attempts to read the oldmem via /proc/vmcore a read from ballooned pages will generate 100% load in dom0 because Xen asks qemu-dm for the page content. Since the reads come in as 8byte requests each ballooned page is tried 512 times. With this change a hook can be registered which checks wether the given pfn is really ram. The hook has to return a value > 0 for ram pages, a value < 0 on error (because the hypercall is not known) and 0 for non-ram pages. This will reduce the time to read /proc/vmcore. Without this change a 512M guest with 128M crashkernel region needs 200 seconds to read it, with this change it takes just 2 seconds. Signed-off-by: Olaf Hering <olaf@aepfle.de> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2011-05-26 17:12:37 -07:00
..
array.c	proc: constify status array	2011-05-26 17:12:36 -07:00
base.c	proc: put check_mem_permission after __get_free_page in mem_write	2011-05-26 17:12:37 -07:00
cmdline.c
consoles.c	console: rename acquire/release_console_sem() to console_lock/unlock()	2011-01-26 10:50:06 +10:00
cpuinfo.c
devices.c	proc: use seq_puts()/seq_putc() where possible	2011-01-13 08:03:16 -08:00
generic.c	airo: correct proc entry creation interfaces	2011-05-16 14:25:28 -04:00
inode.c	ns: proc files for namespace naming policy.	2011-05-10 14:31:44 -07:00
internal.h	Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfd	2011-05-25 18:10:16 -07:00
interrupts.c
Kconfig	kconfig: rename CONFIG_EMBEDDED to CONFIG_EXPERT	2011-01-20 17:02:05 -08:00
kcore.c	/proc/kcore: fix seeking	2011-01-13 08:03:17 -08:00
kmsg.c	procfs: Use generic_file_llseek in /proc/kmsg	2010-04-09 16:35:41 +02:00
loadavg.c
Makefile	ns: proc files for namespace naming policy.	2011-05-10 14:31:44 -07:00
meminfo.c	thp: transparent hugepage vmstat	2011-01-13 17:32:43 -08:00
mmu.c
namespaces.c	ns proc: Return -ENOENT for a nonexistent /proc/self/ns/ entry.	2011-05-24 15:30:33 -07:00
nommu.c
page.c	thp: remove PG_buddy	2011-01-13 17:32:43 -08:00
proc_devtree.c	of/flattree: Drop an uninteresting message to pr_debug level	2011-03-02 13:45:18 -07:00
proc_net.c
proc_sysctl.c	Merge branch 'next' into for-linus	2011-03-16 09:41:17 +11:00
proc_tty.c	proc: use seq_puts()/seq_putc() where possible	2011-01-13 08:03:16 -08:00
root.c	procfs: kill the global proc_mnt variable	2011-03-23 19:46:58 -07:00
softirqs.c	proc: use seq_puts()/seq_putc() where possible	2011-01-13 08:03:16 -08:00
stat.c	proc/stat: use defined macro KMALLOC_MAX_SIZE	2011-05-26 17:12:37 -07:00
task_mmu.c	proc: fix pagemap_read() error case	2011-05-26 17:12:37 -07:00
task_nommu.c	report errors in /proc/*/*map* sanely	2011-03-23 16:36:50 -04:00
uptime.c
version.c
vmcore.c	fs/proc/vmcore.c: add hook to read_from_oldmem() to check for non-ram pages	2011-05-26 17:12:37 -07:00