On Wed, Jan 12, 2022 at 05:45:40PM +0200, Mike Rapoport wrote: > On Wed, Jan 12, 2022 at 01:35:52AM -0700, Yu Zhao wrote: > > On Mon, Jan 10, 2022 at 12:27:19PM +0200, Mike Rapoport wrote: > > > Hi, > > > > > > On Tue, Jan 04, 2022 at 01:22:27PM -0700, Yu Zhao wrote: > > > > Add /sys/kernel/mm/lru_gen/enabled as a runtime kill switch. > > > > > > > > Add /sys/kernel/mm/lru_gen/min_ttl_ms for thrashing prevention. > > > > Compared with the size-based approach, e.g., [1], this time-based > > > > approach has the following advantages: > > > > 1) It's easier to configure because it's agnostic to applications and > > > > memory sizes. > > > > 2) It's more reliable because it's directly wired to the OOM killer. > > > > > > > > Add /sys/kernel/debug/lru_gen for working set estimation and proactive > > > > reclaim. Compared with the page table-based approach and the PFN-based > > > > approach, e.g., mm/damon/[vp]addr.c, this lruvec-based approach has > > > > the following advantages: > > > > 1) It offers better choices because it's aware of memcgs, NUMA nodes, > > > > shared mappings and unmapped page cache. > > > > 2) It's more scalable because it's O(nr_hot_evictable_pages), whereas > > > > the PFN-based approach is O(nr_total_pages). > > > > > > > > Add /sys/kernel/debug/lru_gen_full for debugging. > > > > > > > > [1] https://lore.kernel.org/lkml/20211130201652.2218636d@xxxxxxxxxxxxx/ > > > > > > > > Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx> > > > > Tested-by: Konstantin Kharlamov <Hi-Angel@xxxxxxxxx> > > > > --- > > > > Documentation/vm/index.rst | 1 + > > > > Documentation/vm/multigen_lru.rst | 62 +++++ > > > > > > The description of user visible interfaces should go to > > > Documentation/admin-guide/mm > > > > > > Documentation/vm/multigen_lru.rst should have contained design description > > > and the implementation details and it would be great to actually have such > > > document. > > > > Will do, thanks. > > > > > > include/linux/nodemask.h | 1 + > > > > mm/vmscan.c | 415 ++++++++++++++++++++++++++++++ > > > > 4 files changed, 479 insertions(+) > > > > create mode 100644 Documentation/vm/multigen_lru.rst > > > > > > > > diff --git a/Documentation/vm/index.rst b/Documentation/vm/index.rst > > > > index 6f5ffef4b716..f25e755b4ff4 100644 > > > > --- a/Documentation/vm/index.rst > > > > +++ b/Documentation/vm/index.rst > > > > @@ -38,3 +38,4 @@ algorithms. If you are looking for advice on simply allocating memory, see the > > > > unevictable-lru > > > > z3fold > > > > zsmalloc > > > > + multigen_lru > > > > diff --git a/Documentation/vm/multigen_lru.rst b/Documentation/vm/multigen_lru.rst > > > > new file mode 100644 > > > > index 000000000000..6f9e0181348b > > > > --- /dev/null > > > > +++ b/Documentation/vm/multigen_lru.rst > > > > @@ -0,0 +1,62 @@ > > > > +.. SPDX-License-Identifier: GPL-2.0 > > > > + > > > > +===================== > > > > +Multigenerational LRU > > > > +===================== > > > > + > > > > +Quick start > > > > +=========== > > > > +Runtime configurations > > > > +---------------------- > > > > +:Required: Write ``1`` to ``/sys/kernel/mm/lru_gen/enable`` if the > > > > + feature wasn't enabled by default. > > > > > > Required for what? This sentence seem to lack context. Maybe add an > > > overview what is Multigenerational LRU so that users will have an idea what > > > these knobs control. > > > > Apparently I left an important part of this quick start in the next > > patch, where Kconfig options are added. I'm wonder whether I should > > squash the next patch into this one. > > I think documentation deserves a separate patch. Will do.
