diff options
| author | Alexander Duyck <alexander.h.duyck@linux.intel.com> | 2018-10-26 15:07:45 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-10-26 16:26:34 -0700 |
| commit | f682a97a00591def7cefbb5003dc04045028e405 (patch) | |
| tree | cc526a57d98ef506d9514264439230f19c7478dd /Documentation | |
| parent | 85cfb245060e45640fa3447f8b0bad5e8bd3bdaf (diff) | |
| download | linux-f682a97a00591def7cefbb5003dc04045028e405.tar.bz2 | |
mm: provide kernel parameter to allow disabling page init poisoning
Patch series "Address issues slowing persistent memory initialization", v5.
The main thing this patch set achieves is that it allows us to initialize
each node worth of persistent memory independently. As a result we reduce
page init time by about 2 minutes because instead of taking 30 to 40
seconds per node and going through each node one at a time, we process all
4 nodes in parallel in the case of a 12TB persistent memory setup spread
evenly over 4 nodes.
This patch (of 3):
On systems with a large amount of memory it can take a significant amount
of time to initialize all of the page structs with the PAGE_POISON_PATTERN
value. I have seen it take over 2 minutes to initialize a system with
over 12TB of RAM.
In order to work around the issue I had to disable CONFIG_DEBUG_VM and
then the boot time returned to something much more reasonable as the
arch_add_memory call completed in milliseconds versus seconds. However in
doing that I had to disable all of the other VM debugging on the system.
In order to work around a kernel that might have CONFIG_DEBUG_VM enabled
on a system that has a large amount of memory I have added a new kernel
parameter named "vm_debug" that can be set to "-" in order to disable it.
Link: http://lkml.kernel.org/r/20180925201921.3576.84239.stgit@localhost.localdomain
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 8022d902e770..dcd082576e79 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4839,6 +4839,18 @@ This is actually a boot loader parameter; the value is passed to the kernel using a special protocol. + vm_debug[=options] [KNL] Available with CONFIG_DEBUG_VM=y. + May slow down system boot speed, especially when + enabled on systems with a large amount of memory. + All options are enabled by default, and this + interface is meant to allow for selectively + enabling or disabling specific virtual memory + debugging features. + + Available options are: + P Enable page structure init time poisoning + - Disable all of the above options + vmalloc=nn[KMG] [KNL,BOOT] Forces the vmalloc area to have an exact size of <nn>. This can be used to increase the minimum size (128MB on x86). It can also be used to |