Linux kernel source tree
Find a file
Huang Ying 20b51af15e mm/migrate: add sysfs interface to enable reclaim migration
Some method is obviously needed to enable reclaim-based migration.

Just like traditional autonuma, there will be some workloads that will
benefit like workloads with more "static" configurations where hot pages
stay hot and cold pages stay cold.  If pages come and go from the hot and
cold sets, the benefits of this approach will be more limited.

The benefits are truly workload-based and *not* hardware-based.  We do not
believe that there is a viable threshold where certain hardware
configurations should have this mechanism enabled while others do not.

To be conservative, earlier work defaulted to disable reclaim- based
migration and did not include a mechanism to enable it.  This proposes add
a new sysfs file

  /sys/kernel/mm/numa/demotion_enabled

as a method to enable it.

We are open to any alternative that allows end users to enable this
mechanism or disable it if workload harm is detected (just like
traditional autonuma).

Once this is enabled page demotion may move data to a NUMA node that does
not fall into the cpuset of the allocating process.  This could be
construed to violate the guarantees of cpusets.  However, since this is an
opt-in mechanism, the assumption is that anyone enabling it is content to
relax the guarantees.

Link: https://lkml.kernel.org/r/20210721063926.3024591-9-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20210715055145.195411-10-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Originally-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-09-03 09:58:16 -07:00
arch microblaze: simplify pte_alloc_one_kernel() 2021-09-03 09:58:15 -07:00
block mm: remove flush_kernel_dcache_page 2021-09-03 09:58:13 -07:00
certs
crypto
Documentation mm/migrate: add sysfs interface to enable reclaim migration 2021-09-03 09:58:16 -07:00
drivers mm: sparse: pass section_nr to find_memory_block 2021-09-03 09:58:14 -07:00
fs userfaultfd: prevent concurrent API initialization 2021-09-03 09:58:16 -07:00
include mm/migrate: add sysfs interface to enable reclaim migration 2021-09-03 09:58:16 -07:00
init
ipc memcg: enable accounting of ipc resources 2021-09-03 09:58:12 -07:00
kernel memcg: enable accounting for posix_timers_cache slab 2021-09-03 09:58:13 -07:00
lib kasan: test: avoid corrupting memory in kasan_rcu_uaf 2021-09-03 09:58:15 -07:00
LICENSES
mm mm/migrate: add sysfs interface to enable reclaim migration 2021-09-03 09:58:16 -07:00
net This is a one-liner fix for a serious bug that can cause the server to 2021-08-26 13:26:40 -07:00
samples
scripts
security mm/pagemap: add mmap_assert_locked() annotations to find_vma*() 2021-09-03 09:58:13 -07:00
sound
tools selftests/vm/userfaultfd: wake after copy failure 2021-09-03 09:58:16 -07:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.14 2021-08-29 15:04:50 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.