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We don't need up-to-date accessed-dirty information for anon folios and
can simply work with the ptent we already have. Also, we know the RSS
counter we want to update.
We can safely move arch_check_zapped_pte() + tlb_remove_tlb_entry() +
zap_install_uffd_wp_if_needed() after updating the folio and RSS.
While at it, only call zap_install_uffd_wp_if_needed() if there is even
any chance that pte_install_uffd_wp_if_needed() would do *something*.
That is, just don't bother if uffd-wp does not apply.
Link: https://lkml.kernel.org/r/20240214204435.167852-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We don't need uptodate accessed/dirty bits, so in theory we could replace
ptep_get_and_clear_full() by an optimized ptep_clear_full() function.
Let's rely on the provided pte.
Further, there is no scenario where we would have to insert uffd-wp
markers when zapping something that is not a normal page (i.e., zeropage).
Add a sanity check to make sure this remains true.
should_zap_folio() no longer has to handle NULL pointers. This change
replaces 2/3 "!page/!folio" checks by a single "!page" one.
Note that arch_check_zapped_pte() on x86-64 checks the HW-dirty bit to
detect shadow stack entries. But for shadow stack entries, the HW dirty
bit (in combination with non-writable PTEs) is set by software. So for
the arch_check_zapped_pte() check, we don't have to sync against HW
setting the HW dirty bit concurrently, it is always set.
Link: https://lkml.kernel.org/r/20240214204435.167852-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/memory: optimize unmap/zap with PTE-mapped THP", v3.
This series is based on [1]. Similar to what we did with fork(), let's
implement PTE batching during unmap/zap when processing PTE-mapped THPs.
We collect consecutive PTEs that map consecutive pages of the same large
folio, making sure that the other PTE bits are compatible, and (a) adjust
the refcount only once per batch, (b) call rmap handling functions only
once per batch, (c) perform batch PTE setting/updates and (d) perform TLB
entry removal once per batch.
Ryan was previously working on this in the context of cont-pte for arm64,
int latest iteration [2] with a focus on arm6 with cont-pte only. This
series implements the optimization for all architectures, independent of
such PTE bits, teaches MMU gather/TLB code to be fully aware of such
large-folio-pages batches as well, and amkes use of our new rmap batching
function when removing the rmap.
To achieve that, we have to enlighten MMU gather / page freeing code
(i.e., everything that consumes encoded_page) to process unmapping of
consecutive pages that all belong to the same large folio. I'm being very
careful to not degrade order-0 performance, and it looks like I managed to
achieve that.
While this series should -- similar to [1] -- be beneficial for adding
cont-pte support on arm64[2], it's one of the requirements for maintaining
a total mapcount[3] for large folios with minimal added overhead and
further changes[4] that build up on top of the total mapcount.
Independent of all that, this series results in a speedup during munmap()
and similar unmapping (process teardown, MADV_DONTNEED on larger ranges)
with PTE-mapped THP, which is the default with THPs that are smaller than
a PMD (for example, 16KiB to 1024KiB mTHPs for anonymous memory[5]).
On an Intel Xeon Silver 4210R CPU, munmap'ing a 1GiB VMA backed by
PTE-mapped folios of the same size (stddev < 1%) results in the following
runtimes for munmap() in seconds (shorter is better):
Folio Size | mm-unstable | New | Change
---------------------------------------------
4KiB | 0.058110 | 0.057715 | - 1%
16KiB | 0.044198 | 0.035469 | -20%
32KiB | 0.034216 | 0.023522 | -31%
64KiB | 0.029207 | 0.018434 | -37%
128KiB | 0.026579 | 0.014026 | -47%
256KiB | 0.025130 | 0.011756 | -53%
512KiB | 0.024292 | 0.010703 | -56%
1024KiB | 0.023812 | 0.010294 | -57%
2048KiB | 0.023785 | 0.009910 | -58%
[1] https://lkml.kernel.org/r/20240129124649.189745-1-david@redhat.com
[2] https://lkml.kernel.org/r/20231218105100.172635-1-ryan.roberts@arm.com
[3] https://lkml.kernel.org/r/20230809083256.699513-1-david@redhat.com
[4] https://lkml.kernel.org/r/20231124132626.235350-1-david@redhat.com
[5] https://lkml.kernel.org/r/20231207161211.2374093-1-ryan.roberts@arm.com
This patch (of 10):
Let's prepare for further changes by factoring out processing of present
PTEs.
Link: https://lkml.kernel.org/r/20240214204435.167852-1-david@redhat.com
Link: https://lkml.kernel.org/r/20240214204435.167852-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
It can not improve the fragmentation if we isolate the target free pages
exceeding cc->order, especially when the cc->order is less than
pageblock_order. For example, suppose the pageblock_order is MAX_ORDER
(size is 4M) and cc->order is 2M THP size, we should not isolate other 2M
free pages to be the migration target, which can not improve the
fragmentation.
Moreover this is also applicable for large folio compaction.
Link: https://lkml.kernel.org/r/afcd9377351c259df7a25a388a4a0d5862b986f4.1705928395.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All platforms could benefit from page order check against MAX_PAGE_ORDER
before allocating a CMA area for gigantic hugetlb pages. Let's move this
check from individual platforms to generic hugetlb.
Link: https://lkml.kernel.org/r/20240209054221.1403364-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The reclaimable number of anon pages used to set initial reclaim priority
is only based on get_swappiness(). Use can_reclaim_anon_pages() to
include NUMA node demotion.
Also move the swappiness handling of when !__GFP_IO in
try_to_shrink_lruvec() into isolate_folios().
Link: https://lkml.kernel.org/r/20240214060538.3524462-6-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Donet Tom <donettom@linux.vnet.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Rename max_seq to seq in struct lru_gen_mm_walk to keep consistent with
struct lru_gen_mm_state. Note that seq is not always up to date with
max_seq from lru_gen_folio.
No functional changes.
Link: https://lkml.kernel.org/r/20240214060538.3524462-5-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Donet Tom <donettom@linux.vnet.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
struct lruvec* is already a field of struct lru_gen_mm_walk. Remove the
parameter struct lruvec* into functions that already have access to struct
lru_gen_mm_walk*.
Also, we do not need to handle reset histogram stats when
!should_walk_mmu(). Remove the call to reset_mm_stats() in
iterate_mm_list_nowalk().
Link: https://lkml.kernel.org/r/20240214060538.3524462-4-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Donet Tom <donettom@linux.vnet.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
scan_control *sc does not need to be passed into should_run_aging(), as it
provides only the reclaim priority. This can be moved to
get_nr_to_scan().
Refactor should_run_aging() and get_nr_to_scan() to improve code
readability. No functional changes.
Link: https://lkml.kernel.org/r/20240214060538.3524462-3-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Donet Tom <donettom@linux.vnet.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mglru: code cleanup and refactoring"
This provides MGLRU code cleanup and refactoring for better readability.
This patch (of 5):
struct scan_control *sc is currently passed into try_to_inc_max_seq() and
run_aging(). This parameter is not used.
Drop the unused parameter struct scan_control *sc. No functional change.
Link: https://lkml.kernel.org/r/20240214060538.3524462-1-kinseyho@google.com
Link: https://lkml.kernel.org/r/20240214060538.3524462-2-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Donet Tom <donettom@linux.vnet.ibm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The out-of-bounds test allocates an object that is three bytes too short
in order to validate the bounds checking. Starting with gcc-14, this
causes a compile-time warning as gcc has grown smart enough to understand
the sizeof() logic:
mm/kasan/kasan_test.c: In function 'kmalloc_oob_16':
mm/kasan/kasan_test.c:443:14: error: allocation of insufficient size '13' for type 'struct <anonymous>' with size '16' [-Werror=alloc-size]
443 | ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
| ^
Hide the actual computation behind a RELOC_HIDE() that ensures
the compiler misses the intentional bug.
Link: https://lkml.kernel.org/r/20240212111609.869266-1-arnd@kernel.org
Fixes: 3f15801cdc23 ("lib: add kasan test module")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We may encounter duplicate entry in the zswap_store():
1. swap slot that freed to per-cpu swap cache, doesn't invalidate
the zswap entry, then got reused. This has been fixed.
2. !exclusive load mode, swapin folio will leave its zswap entry
on the tree, then swapout again. This has been removed.
3. one folio can be dirtied again after zswap_store(), so need to
zswap_store() again. This should be handled correctly.
So we must invalidate the old duplicate entry before inserting the
new one, which actually doesn't have to be done at the beginning
of zswap_store().
The good point is that we don't need to lock the tree twice in the normal
store success path. And cleanup the loop as we are here.
Note we still need to invalidate the old duplicate entry when store failed
or zswap is disabled , otherwise the new data in swapfile could be
overwrite by the old data in zswap pool when lru writeback.
Link: https://lkml.kernel.org/r/20240209044112.3883835-1-chengming.zhou@linux.dev
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Chris Li <chrisl@kernel.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Refactor compact_node() to handle both proactive and synchronous compact
memory, which cleanups code a bit.
Link: https://lkml.kernel.org/r/20240208013607.1731817-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This adds the following new sysfs file tracking the number of successfully
released pages from a given CMA heap area. This file will be available
via CONFIG_CMA_SYSFS and help in determining active CMA pages available on
the CMA heap area. This adds a new 'nr_pages_released' (CONFIG_CMA_SYSFS)
into 'struct cma' which gets updated during cma_release().
/sys/kernel/mm/cma/<cma-heap-area>/release_pages_success
After this change, an user will be able to find active CMA pages available
in a given CMA heap area via the following method.
Active pages = alloc_pages_success - release_pages_success
That's valuable information for both software designers, and system admins
as it allows them to tune the number of CMA pages available in the system.
This increases user visibility for allocated CMA area and its
utilization.
Link: https://lkml.kernel.org/r/20240206045731.472759-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, when a demotion occurs, it will prioritize selecting a node
from the preferred targets as the destination node for the demotion. If
the preferred node does not meet the requirements, it will try from all
the lower memory tier nodes until it finds a suitable demotion destination
node or ultimately fails.
However, the demotion target information isn't exposed to the users,
especially the preferred target information, which relies on more factors.
This makes it hard for users to understand the exact demotion behavior.
Rather than having a new sysfs interface to expose this information,
printing directly to kernel messages, just like the current page
allocation fallback order does.
A dmesg example with this patch is as follows:
[ 0.704860] Demotion targets for Node 0: null
[ 0.705456] Demotion targets for Node 1: null
// node 2 is onlined
[ 32.259775] Demotion targets for Node 0: perferred: 2, fallback: 2
[ 32.261290] Demotion targets for Node 1: perferred: 2, fallback: 2
[ 32.262726] Demotion targets for Node 2: null
// node 3 is onlined
[ 42.448809] Demotion targets for Node 0: perferred: 2, fallback: 2-3
[ 42.450704] Demotion targets for Node 1: perferred: 2, fallback: 2-3
[ 42.452556] Demotion targets for Node 2: perferred: 3, fallback: 3
[ 42.454136] Demotion targets for Node 3: null
// node 4 is onlined
[ 52.676833] Demotion targets for Node 0: perferred: 2, fallback: 2-4
[ 52.678735] Demotion targets for Node 1: perferred: 2, fallback: 2-4
[ 52.680493] Demotion targets for Node 2: perferred: 4, fallback: 3-4
[ 52.682154] Demotion targets for Node 3: null
[ 52.683405] Demotion targets for Node 4: null
// node 5 is onlined
[ 62.931902] Demotion targets for Node 0: perferred: 2, fallback: 2-5
[ 62.938266] Demotion targets for Node 1: perferred: 5, fallback: 2-5
[ 62.943515] Demotion targets for Node 2: perferred: 4, fallback: 3-4
[ 62.947471] Demotion targets for Node 3: null
[ 62.949908] Demotion targets for Node 4: null
[ 62.952137] Demotion targets for Node 5: perferred: 3, fallback: 3-4
Regarding this requirement, we have previously discussed [1]. The initial
proposal involved introducing a new sysfs interface. However, due to
concerns about potential changes and compatibility issues with the
interface in the future, a consensus was not reached with the community.
Therefore, this time, we are directly printing out the information.
[1] https://lore.kernel.org/all/d1d5add8-8f4a-4578-8bf0-2cbe79b09989@fujitsu.com/
Link: https://lkml.kernel.org/r/20240206020151.605516-1-lizhijian@fujitsu.com
Signed-off-by: Li Zhijian <lizhijian@fujitsu.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON sysfs interface need to access kdamond-touching data for some of
kdamond user commands. It uses ->after_aggregation() kdamond callback to
safely access the data in the case. It had to use the aggregation
interval callback because that was the only callback that users can access
complete monitoring results.
Since patch series "mm/damon: provide pseudo-moving sum based access
rate", which starts from commit 78fbfb155d20 ("mm/damon/core: define and
use a dedicated function for region access rate update"), DAMON provides
good-to-use quality moitoring results for every sampling interval. It
aims to help users who need to quickly retrieve the monitoring results.
When the aggregation interval is set too long and therefore waiting for
the aggregation interval can degrade user experience, or when the access
pattern is expected to be significantly changed[1] could be such cases.
However, because DAMON sysfs interface is still handling the commands per
aggregation interval, the end user cannot get the benefit. Update DAMON
sysfs interface to handle kdamond commands for every sampling interval if
applicable. Specifically, all kdamond data accessing commands except
'commit' command are applicable.
[1] https://lore.kernel.org/r/20240129121316.GA9706@cuiyangpei
Link: https://lkml.kernel.org/r/20240206025158.203097-1-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: xiongping1 <xiongping1@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
alloc_and_dissolve_hugetlb_folio() preallocates a new hugetlb page before
it takes hugetlb_lock. In 3 out of 4 cases the page is not really used
and therefore the newly allocated page is just freed right away. This is
wasteful and it might cause pre-mature failures in those cases.
Address that by moving the allocation down to the only case (hugetlb page
is really in the free pages pool). We need to drop hugetlb_lock to do so
and therefore need to recheck the page state after regaining it.
The patch is more of a cleanup than an actual fix to an existing problem.
There are no known reports about pre-mature failures.
Link: https://lkml.kernel.org/r/62890fd60b1ecd5bf1cdc476c973f60fe37aa0cb.1707181934.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
pte_mkdirty() sets both _PAGE_DIRTY and _PAGE_SOFT_DIRTY bits. The
_PAGE_SOFT_DIRTY can get set even if it wasn't set on original page before
migration. This makes non-soft-dirty pages soft-dirty just because of
migration/compaction. Clear the _PAGE_SOFT_DIRTY flag if it wasn't set on
original page.
By definition of soft-dirty feature, there can be spurious soft-dirty
pages because of kernel's internal activity such as VMA merging or
migration/compaction. This patch is eliminating the spurious soft-dirty
pages because of migration/compaction.
Link: https://lkml.kernel.org/r/20240206084838.34560-1-usama.anjum@collabora.com
Signed-off-by: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Andrei Vagin <avagin@gmail.com>
Cc: Michał Mirosław <emmir@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Since we don't need to leave zswap entry on the zswap tree anymore,
we should remove it from tree once we find it from the tree.
Then after using it, we can directly free it, no concurrent path
can find it from tree. Only the shrinker can see it from lru list,
which will also double check under tree lock, so no race problem.
So we don't need refcount in zswap entry anymore and don't need to
take the spinlock for the second time to invalidate it.
The side effect is that zswap_entry_free() maybe not happen in tree
spinlock, but it's ok since nothing need to be protected by the lock.
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-6-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The !zswap_exclusive_loads_enabled mode will leave compressed copy in
the zswap tree and lru list after the folio swapin.
There are some disadvantages in this mode:
1. It's a waste of memory since there are two copies of data, one is
folio, the other one is compressed data in zswap. And it's unlikely
the compressed data is useful in the near future.
2. If that folio is dirtied, the compressed data must be not useful,
but we don't know and don't invalidate the trashy memory in zswap.
3. It's not reclaimable from zswap shrinker since zswap_writeback_entry()
will always return -EEXIST and terminate the shrinking process.
On the other hand, the only downside of zswap_exclusive_loads_enabled
is a little more cpu usage/latency when compression, and the same if
the folio is removed from swapcache or dirtied.
More explanation by Johannes on why we should consider exclusive load
as the default for zswap:
Caching "swapout work" is helpful when the system is thrashing. Then
recently swapped in pages might get swapped out again very soon. It
certainly makes sense with conventional swap, because keeping a clean
copy on the disk saves IO work and doesn't cost any additional memory.
But with zswap, it's different. It saves some compression work on a
thrashing page. But the act of keeping compressed memory contributes
to a higher rate of thrashing. And that can cause IO in other places
like zswap writeback and file memory.
And the A/B test results of the kernel build in tmpfs with limited memory
can support this theory:
!exclusive exclusive
real 63.80 63.01
user 1063.83 1061.32
sys 290.31 266.15
workingset_refault_anon 2383084.40 1976397.40
workingset_refault_file 44134.00 45689.40
workingset_activate_anon 837878.00 728441.20
workingset_activate_file 4710.00 4085.20
workingset_restore_anon 732622.60 639428.40
workingset_restore_file 1007.00 926.80
workingset_nodereclaim 0.00 0.00
pgscan 14343003.40 12409570.20
pgscan_kswapd 0.00 0.00
pgscan_direct 14343003.40 12409570.20
pgscan_khugepaged 0.00 0.00
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-5-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
cat /sys/kernel/debug/zswap/duplicate_entry
2086447
When testing, the duplicate_entry value is very high, but no warning
message in the kernel log. From the comment of duplicate_entry "Duplicate
store was encountered (rare)", it seems something goes wrong.
Actually it's incremented in the beginning of zswap_store(), which found
its zswap entry has already on the tree. And this is a normal case, since
the folio could leave zswap entry on the tree after swapin, later it's
dirtied and swapout/zswap_store again, found its original zswap entry.
So duplicate_entry should be only incremented in the real bug case, which
already have "WARN_ON(1)", it looks redundant to count bug case, so this
patch just remove it.
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-4-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When the shrinker encounter an existing folio in swap cache, it means we
are shrinking into the warmer region. We should terminate shrinking if
we're in the dynamic shrinker context.
This patch add LRU_STOP to support this, to avoid overshrinking.
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-3-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
During testing I found there are some times the zswap_writeback_entry()
return -ENOMEM, which is not we expected:
bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}'
@[-12]: 1563
@[0]: 277221
The reason is that __read_swap_cache_async() return NULL because
swapcache_prepare() failed. The reason is that we won't invalidate zswap
entry when swap entry freed to the per-cpu pool, these zswap entries are
still on the zswap tree and lru list.
This patch moves the invalidation ahead to when swap entry freed to the
per-cpu pool, since there is no any benefit to leave trashy zswap entry on
the tree and lru list.
With this patch:
bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}'
@[0]: 259744
Note: large folio can't have zswap entry for now, so don't bother
to add zswap entry invalidation in the large folio swap free path.
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-2-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/zswap: optimize zswap lru list", v2.
This series is motivated when observe the zswap lru list shrinking, noted
there are some unexpected cases in zswap_writeback_entry().
bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}'
There are some -ENOMEM because when the swap entry is freed to per-cpu
swap pool, it doesn't invalidate/drop zswap entry. Then the shrinker
encounter these trashy zswap entries, it can't be reclaimed and return
-ENOMEM.
So move the invalidation ahead to when swap entry freed to the per-cpu
swap pool, since there is no any benefit to leave trashy zswap entries on
the zswap tree and lru list.
Another case is -EEXIST, which is seen more in the case of
!zswap_exclusive_loads_enabled, in which case the swapin folio will leave
compressed copy on the tree and lru list. And it can't be reclaimed until
the folio is removed from swapcache.
Changing to zswap_exclusive_loads_enabled mode will invalidate when folio
swapin, which has its own drawback if that folio is still clean in
swapcache and swapout again, we need to compress it again. Please see the
commit for details on why we choose exclusive load as the default for
zswap.
Another optimization for -EEXIST is that we add LRU_STOP to support
terminating the shrinking process to avoid evicting warmer region.
Testing using kernel build in tmpfs, one 50GB swapfile and
zswap shrinker_enabled, with memory.max set to 2GB.
mm-unstable zswap-optimize
real 63.90s 63.25s
user 1064.05s 1063.40s
sys 292.32s 270.94s
The main optimization is in sys cpu, about 7% improvement.
This patch (of 6):
Add more comments in shrink_memcg_cb() to describe the deref dance which
is implemented to fix race problem between lru writeback and swapoff, and
the reason why we rotate the entry at the beginning.
Also fix the stale comments in zswap_writeback_entry(), and add more
comments to state that we only deref the tree after we get the swapcache
reference.
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-0-99d4084260a0@bytedance.com
Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-1-99d4084260a0@bytedance.com
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Now that the driver core can properly handle constant struct bus_type,
move the memory_tier_subsys variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.
Link: https://lkml.kernel.org/r/20240204-bus_cleanup-mm-v1-1-00f49286f164@marliere.net
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
too_many_isolated() should return bool as does the similar
too_many_isolated() in mm/compaction.c.
Link: https://lkml.kernel.org/r/20240205042618.108140-1-gehao@kylinos.cn
Signed-off-by: Hao Ge <gehao@kylinos.cn>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
There is no real difference between the global area, and other
additionally configured CMA areas via CONFIG_CMA_AREAS that always
defaults without user input. This makes MAX_CMA_AREAS same as
CONFIG_CMA_AREAS, also incrementing its default values, thus maintaining
current default for MAX_CMA_AREAS both for UMA and NUMA systems.
Link: https://lkml.kernel.org/r/20240205051929.298559-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
All pr_debug() prints in (mm/cma.c) could be enabled via standard Makefile
based method. Besides cma_debug_show_areas() should always be called
during cma_alloc() failure path. This seemingly redundant config,
CONFIG_CMA_DEBUG can be dropped without any problem.
[lukas.bulwahn@gmail.com: remove debug code to removed CONFIG_CMA_DEBUG]
Link: https://lkml.kernel.org/r/20240207143825.986-1-lukas.bulwahn@gmail.com
Link: https://lkml.kernel.org/r/20240205031647.283510-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After commit f7e01ab828fd ("kasan: move tests to mm/kasan/"), the test
module file is renamed from lib/test_kasan_module.c to
mm/kasan/kasan_test_module.c, in order to keep consistent, rename
test_kasan_module_init to kasan_test_module_init.
Link: https://lkml.kernel.org/r/20240205060925.15594-3-yangtiezhu@loongson.cn
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/hugetlb: Restore the reservation", v2.
This is a fix for a case where a backing huge page could stolen after
madvise(MADV_DONTNEED).
A full reproducer is in selftest. See
https://lore.kernel.org/all/20240105155419.1939484-1-leitao@debian.org/
In order to test this patch, I instrumented the kernel with LOCKDEP and
KASAN, and run the following tests, without any regression:
* The self test that reproduces the problem
* All mm hugetlb selftests
SUMMARY: PASS=9 SKIP=0 FAIL=0
* All libhugetlbfs tests
PASS: 0 86
FAIL: 0 0
This patch (of 2):
Currently there is a bug that a huge page could be stolen, and when the
original owner tries to fault in it, it causes a page fault.
You can achieve that by:
1) Creating a single page
echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
2) mmap() the page above with MAP_HUGETLB into (void *ptr1).
* This will mark the page as reserved
3) touch the page, which causes a page fault and allocates the page
* This will move the page out of the free list.
* It will also unreserved the page, since there is no more free
page
4) madvise(MADV_DONTNEED) the page
* This will free the page, but not mark it as reserved.
5) Allocate a secondary page with mmap(MAP_HUGETLB) into (void *ptr2).
* it should fail, but, since there is no more available page.
* But, since the page above is not reserved, this mmap() succeed.
6) Faulting at ptr1 will cause a SIGBUS
* it will try to allocate a huge page, but there is none
available
A full reproducer is in selftest. See
https://lore.kernel.org/all/20240105155419.1939484-1-leitao@debian.org/
Fix this by restoring the reserved page if necessary.
These are the condition for the page restore:
* The system is not using surplus pages. The goal is to reduce the
surplus usage for this case.
* If the VMA has the HPAGE_RESV_OWNER flag set, and is PRIVATE. This is
safely checked using __vma_private_lock()
* The page is anonymous
Once this is scenario is found, set the `hugetlb_restore_reserve` bit in
the folio. Then check if the resv reservations need to be adjusted
later, done later, after the spinlock, since the vma_xxxx_reservation()
might touch the file system lock.
Link: https://lkml.kernel.org/r/20240205191843.4009640-1-leitao@debian.org
Link: https://lkml.kernel.org/r/20240205191843.4009640-2-leitao@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Suggested-by: Rik van Riel <riel@surriel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Test that KASan can detect some unsafe atomic accesses.
As discussed in the linked thread below, these tests attempt to cover
the most common uses of atomics and, therefore, aren't exhaustive.
Link: https://lkml.kernel.org/r/20240202113259.3045705-1-paul.heidekrueger@tum.de
Link: https://lore.kernel.org/all/20240131210041.686657-1-paul.heidekrueger@tum.de/T/#u
Signed-off-by: Paul Heidekrüger <paul.heidekrueger@tum.de>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=214055
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Before 388536ac291 ("mm:vmscan: fix inaccurate reclaim during proactive
reclaim") we passed the number of pages for the reclaim request directly
to try_to_free_mem_cgroup_pages, which could lead to significant
overreclaim. After 0388536ac291 the number of pages was limited to a
maximum 32 (SWAP_CLUSTER_MAX) to reduce the amount of overreclaim.
However such a small batch size caused a regression in reclaim performance
due to many more reclaim start/stop cycles inside memory_reclaim. The
restart cost is amortized over more pages with larger batch sizes, and
becomes a significant component of the runtime if the batch size is too
small.
Reclaim tries to balance nr_to_reclaim fidelity with fairness across nodes
and cgroups over which the pages are spread. As such, the bigger the
request, the bigger the absolute overreclaim error. Historic in-kernel
users of reclaim have used fixed, small sized requests to approach an
appropriate reclaim rate over time. When we reclaim a user request of
arbitrary size, use decaying batch sizes to manage error while maintaining
reasonable throughput.
MGLRU enabled - memcg LRU used
root - full reclaim pages/sec time (sec)
pre-0388536ac291 : 68047 10.46
post-0388536ac291 : 13742 inf
(reclaim-reclaimed)/4 : 67352 10.51
MGLRU enabled - memcg LRU not used
/uid_0 - 1G reclaim pages/sec time (sec) overreclaim (MiB)
pre-0388536ac291 : 258822 1.12 107.8
post-0388536ac291 : 105174 2.49 3.5
(reclaim-reclaimed)/4 : 233396 1.12 -7.4
MGLRU enabled - memcg LRU not used
/uid_0 - full reclaim pages/sec time (sec)
pre-0388536ac291 : 72334 7.09
post-0388536ac291 : 38105 14.45
(reclaim-reclaimed)/4 : 72914 6.96
[tjmercier@google.com: v4]
Link: https://lkml.kernel.org/r/20240206175251.3364296-1-tjmercier@google.com
Link: https://lkml.kernel.org/r/20240202233855.1236422-1-tjmercier@google.com
Fixes: 0388536ac291 ("mm:vmscan: fix inaccurate reclaim during proactive reclaim")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Michal Koutny <mkoutny@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Efly Young <yangyifei03@kuaishou.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
These vma_merge() callers will pass mm, anon_vma and file, they all from
the same vma. There is no need to pass three parameters at the same time.
Pass vma instead of mm, anon_vma and file to vma_merge(), so that it can
save two parameters.
Link: https://lkml.kernel.org/r/20240203014632.2726545-1-yajun.deng@linux.dev
Link: https://lore.kernel.org/lkml/20240125034922.1004671-2-yajun.deng@linux.dev/
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
... and conditionally return to the caller if any PTE except the first
one is writable. fork() has to make sure to properly write-protect in
case any PTE is writable. Other users (e.g., page unmaping) are expected
to not care.
Link: https://lkml.kernel.org/r/20240129124649.189745-16-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's always ignore the accessed/young bit: we'll always mark the PTE as
old in our child process during fork, and upcoming users will similarly
not care.
Ignore the dirty bit only if we don't want to duplicate the dirty bit into
the child process during fork. Maybe, we could just set all PTEs in the
child dirty if any PTE is dirty. For now, let's keep the behavior
unchanged, this can be optimized later if required.
Ignore the soft-dirty bit only if the bit doesn't have any meaning in the
src vma, and similarly won't have any in the copied dst vma.
For now, we won't bother with the uffd-wp bit.
Link: https://lkml.kernel.org/r/20240129124649.189745-15-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's implement PTE batching when consecutive (present) PTEs map
consecutive pages of the same large folio, and all other PTE bits besides
the PFNs are equal.
We will optimize folio_pte_batch() separately, to ignore selected PTE
bits. This patch is based on work by Ryan Roberts.
Use __always_inline for __copy_present_ptes() and keep the handling for
single PTEs completely separate from the multi-PTE case: we really want
the compiler to optimize for the single-PTE case with small folios, to not
degrade performance.
Note that PTE batching will never exceed a single page table and will
always stay within VMA boundaries.
Further, processing PTE-mapped THP that maybe pinned and have
PageAnonExclusive set on at least one subpage should work as expected, but
there is room for improvement: We will repeatedly (1) detect a PTE batch
(2) detect that we have to copy a page (3) fall back and allocate a single
page to copy a single page. For now we won't care as pinned pages are a
corner case, and we should rather look into maintaining only a single
PageAnonExclusive bit for large folios.
Link: https://lkml.kernel.org/r/20240129124649.189745-14-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We already read it, let's just forward it.
This patch is based on work by Ryan Roberts.
[david@redhat.com: fix the hmm "exclusive_cow" selftest]
Link: https://lkml.kernel.org/r/13f296b8-e882-47fd-b939-c2141dc28717@redhat.com
Link: https://lkml.kernel.org/r/20240129124649.189745-13-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Let's prepare for further changes.
Link: https://lkml.kernel.org/r/20240129124649.189745-12-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently we will use 'cc->nr_freepages >= cc->nr_migratepages' comparison
to ensure that enough freepages are isolated in isolate_freepages(),
however it just decreases the cc->nr_freepages without updating
cc->nr_migratepages in compaction_alloc(), which will waste more CPU
cycles and cause too many freepages to be isolated.
So we should also update the cc->nr_migratepages when allocating or
freeing the freepages to avoid isolating excess freepages. And I can see
fewer free pages are scanned and isolated when running thpcompact on my
Arm64 server:
k6.7 k6.7_patched
Ops Compaction pages isolated 120692036.00 118160797.00
Ops Compaction migrate scanned 131210329.00 154093268.00
Ops Compaction free scanned 1090587971.00 1080632536.00
Ops Compact scan efficiency 12.03 14.26
Moreover, I did not see an obvious latency improvements, this is likely
because isolating freepages is not the bottleneck in the thpcompact test
case.
k6.7 k6.7_patched
Amean fault-both-1 1089.76 ( 0.00%) 1080.16 * 0.88%*
Amean fault-both-3 1616.48 ( 0.00%) 1636.65 * -1.25%*
Amean fault-both-5 2266.66 ( 0.00%) 2219.20 * 2.09%*
Amean fault-both-7 2909.84 ( 0.00%) 2801.90 * 3.71%*
Amean fault-both-12 4861.26 ( 0.00%) 4733.25 * 2.63%*
Amean fault-both-18 7351.11 ( 0.00%) 6950.51 * 5.45%*
Amean fault-both-24 9059.30 ( 0.00%) 9159.99 * -1.11%*
Amean fault-both-30 10685.68 ( 0.00%) 11399.02 * -6.68%*
Link: https://lkml.kernel.org/r/6440493f18da82298152b6305d6b41c2962a3ce6.1708409245.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Current implementation of UFFDIO_MOVE fails to move zeropages and returns
EBUSY when it encounters one. We can handle them by mapping a zeropage at
the destination and clearing the mapping at the source. This is done both
for ordinary and for huge zeropages.
Link: https://lkml.kernel.org/r/20240131175618.2417291-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202401300107.U8iMAkTl-lkp@intel.com/
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Nicolas Geoffray <ngeoffray@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: ZhangPeng <zhangpeng362@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Invalid cma_alloc() input scenarios - including excess allocation request
should neither be counted as CMA_ALLOC_FAIL nor 'cma->nr_pages_failed' be
updated when applicable with CONFIG_CMA_SYSFS. This also drops 'out' jump
label which has become redundant.
Link: https://lkml.kernel.org/r/20240201023714.3871061-1-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add a readable attribute in debugfs to trigger a W^X pages check at any
time.
To trigger the test, just read /sys/kernel/debug/check_wx_pages It will
report FAILED if the test failed, SUCCESS otherwise.
Detailed result is provided into dmesg.
Link: https://lkml.kernel.org/r/e947fb1a9f3f5466344823e532d343ff194ae03d.1706610398.git.christophe.leroy@csgroup.eu
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "Aneesh Kumar K.V (IBM)" <aneesh.kumar@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg KH <greg@kroah.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Phong Tran <tranmanphong@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Steven Price <steven.price@arm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
In the event of rebind, pol->nodemask can change at the same time as an
allocation occurs. We can detect this with tsk->mems_allowed_seq and
prevent a miscount or an allocation failure from occurring.
The same thing happens in the allocators to detect failure, but this can
prevent spurious failures in a much smaller critical section.
[gourry.memverge@gmail.com: weighted interleave checks wrong parameter]
Link: https://lkml.kernel.org/r/20240206192853.3589-1-gregory.price@memverge.com
Link: https://lkml.kernel.org/r/20240202170238.90004-5-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When a system has multiple NUMA nodes and it becomes bandwidth hungry,
using the current MPOL_INTERLEAVE could be an wise option.
However, if those NUMA nodes consist of different types of memory such as
socket-attached DRAM and CXL/PCIe attached DRAM, the round-robin based
interleave policy does not optimally distribute data to make use of their
different bandwidth characteristics.
Instead, interleave is more effective when the allocation policy follows
each NUMA nodes' bandwidth weight rather than a simple 1:1 distribution.
This patch introduces a new memory policy, MPOL_WEIGHTED_INTERLEAVE,
enabling weighted interleave between NUMA nodes. Weighted interleave
allows for proportional distribution of memory across multiple numa nodes,
preferably apportioned to match the bandwidth of each node.
For example, if a system has 1 CPU node (0), and 2 memory nodes (0,1),
with bandwidth of (100GB/s, 50GB/s) respectively, the appropriate weight
distribution is (2:1).
Weights for each node can be assigned via the new sysfs extension:
/sys/kernel/mm/mempolicy/weighted_interleave/
For now, the default value of all nodes will be `1`, which matches the
behavior of standard 1:1 round-robin interleave. An extension will be
added in the future to allow default values to be registered at kernel and
device bringup time.
The policy allocates a number of pages equal to the set weights. For
example, if the weights are (2,1), then 2 pages will be allocated on node0
for every 1 page allocated on node1.
The new flag MPOL_WEIGHTED_INTERLEAVE can be used in set_mempolicy(2)
and mbind(2).
Some high level notes about the pieces of weighted interleave:
current->il_prev:
Tracks the node previously allocated from.
current->il_weight:
The active weight of the current node (current->il_prev)
When this reaches 0, current->il_prev is set to the next node
and current->il_weight is set to the next weight.
weighted_interleave_nodes:
Counts the number of allocations as they occur, and applies the
weight for the current node. When the weight reaches 0, switch
to the next node. Operates only on task->mempolicy.
weighted_interleave_nid:
Gets the total weight of the nodemask as well as each individual
node weight, then calculates the node based on the given index.
Operates on VMA policies.
bulk_array_weighted_interleave:
Gets the total weight of the nodemask as well as each individual
node weight, then calculates the number of "interleave rounds" as
well as any delta ("partial round"). Calculates the number of
pages for each node and allocates them.
If a node was scheduled for interleave via interleave_nodes, the
current weight will be allocated first.
Operates only on the task->mempolicy.
One piece of complexity is the interaction between a recent refactor which
split the logic to acquire the "ilx" (interleave index) of an allocation
and the actually application of the interleave. If a call to
alloc_pages_mpol() were made with a weighted-interleave policy and ilx set
to NO_INTERLEAVE_INDEX, weighted_interleave_nodes() would operate on a VMA
policy - violating the description above.
An inspection of all callers of alloc_pages_mpol() shows that all external
callers set ilx to `0`, an index value, or will call get_vma_policy() to
acquire the ilx.
For example, mm/shmem.c may call into alloc_pages_mpol. The call stacks
all set (pgoff_t ilx) or end up in `get_vma_policy()`. This enforces the
`weighted_interleave_nodes()` and `weighted_interleave_nid()` policy
requirements (task/vma respectively).
Link: https://lkml.kernel.org/r/20240202170238.90004-4-gregory.price@memverge.com
Suggested-by: Hasan Al Maruf <Hasan.Maruf@amd.com>
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Co-developed-by: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Co-developed-by: Honggyu Kim <honggyu.kim@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Co-developed-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Signed-off-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Co-developed-by: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Co-developed-by: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Signed-off-by: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move the use of barrier() to force policy->nodemask onto the stack into a
function `read_once_policy_nodemask` so that it may be re-used.
Link: https://lkml.kernel.org/r/20240202170238.90004-3-gregory.price@memverge.com
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Suggested-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Honggyu Kim <honggyu.kim@sk.com>
Cc: Hyeongtak Ji <hyeongtak.ji@sk.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Ravi Jonnalagadda <ravis.opensrc@micron.com>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/mempolicy: weighted interleave mempolicy and sysfs
extension", v5.
Weighted interleave is a new interleave policy intended to make use of
heterogeneous memory environments appearing with CXL.
The existing interleave mechanism does an even round-robin distribution of
memory across all nodes in a nodemask, while weighted interleave
distributes memory across nodes according to a provided weight. (Weight =
# of page allocations per round)
Weighted interleave is intended to reduce average latency when bandwidth
is pressured - therefore increasing total throughput.
In other words: It allows greater use of the total available bandwidth in
a heterogeneous hardware environment (different hardware provides
different bandwidth capacity).
As bandwidth is pressured, latency increases - first linearly and then
exponentially. By keeping bandwidth usage distributed according to
available bandwidth, we therefore can reduce the average latency of a
cacheline fetch.
A good explanation of the bandwidth vs latency response curve:
https://mahmoudhatem.wordpress.com/2017/11/07/memory-bandwidth-vs-latency-response-curve/
From the article:
```
Constant region:
The latency response is fairly constant for the first 40%
of the sustained bandwidth.
Linear region:
In between 40% to 80% of the sustained bandwidth, the
latency response increases almost linearly with the bandwidth
demand of the system due to contention overhead by numerous
memory requests.
Exponential region:
Between 80% to 100% of the sustained bandwidth, the memory
latency is dominated by the contention latency which can be
as much as twice the idle latency or more.
Maximum sustained bandwidth :
Is 65% to 75% of the theoretical maximum bandwidth.
```
As a general rule of thumb:
* If bandwidth usage is low, latency does not increase. It is
optimal to place data in the nearest (lowest latency) device.
* If bandwidth usage is high, latency increases. It is optimal
to place data such that bandwidth use is optimized per-device.
This is the top line goal: Provide a user a mechanism to target using the
"maximum sustained bandwidth" of each hardware component in a heterogenous
memory system.
For example, the stream benchmark demonstrates that 1:1 (default)
interleave is actively harmful, while weighted interleave can be
beneficial. Default interleave distributes data such that too much
pressure is placed on devices with lower available bandwidth.
Stream Benchmark (vs DRAM, 1 Socket + 1 CXL Device)
Default interleave : -78% (slower than DRAM)
Global weighting : -6% to +4% (workload dependant)
Targeted weights : +2.5% to +4% (consistently better than DRAM)
Global means the task-policy was set (set_mempolicy), while targeted means
VMA policies were set (mbind2). We see weighted interleave is not always
beneficial when applied globally, but is always beneficial when applied to
bandwidth-driving memory regions.
There are 4 patches in this set:
1) Implement system-global interleave weights as sysfs extension
in mm/mempolicy.c. These weights are RCU protected, and a
default weight set is provided (all weights are 1 by default).
In future work, we intend to expose an interface for HMAT/CDAT
code to set reasonable default values based on the memory
configuration of the system discovered at boot/hotplug.
2) A mild refactor of some interleave-logic for re-use in the
new weighted interleave logic.
3) MPOL_WEIGHTED_INTERLEAVE extension for set_mempolicy/mbind
4) Protect interleave logic (weighted and normal) with the
mems_allowed seq cookie. If the nodemask changes while
accessing it during a rebind, just retry the access.
Included below are some performance and LTP test information,
and a sample numactl branch which can be used for testing.
= Performance summary =
(tests may have different configurations, see extended info below)
1) MLC (W2) : +38% over DRAM. +264% over default interleave.
MLC (W5) : +40% over DRAM. +226% over default interleave.
2) Stream : -6% to +4% over DRAM, +430% over default interleave.
3) XSBench : +19% over DRAM. +47% over default interleave.
= LTP Testing Summary =
existing mempolicy & mbind tests: pass
mempolicy & mbind + weighted interleave (global weights): pass
= version history
v5:
- style fixes
- mems_allowed cookie protection to detect rebind issues,
prevents spurious allocation failures and/or mis-allocations
- sparse warning fixes related to __rcu on local variables
=====================================================================
Performance tests - MLC
From - Ravi Jonnalagadda <ravis.opensrc@micron.com>
Hardware: Single-socket, multiple CXL memory expanders.
Workload: W2
Data Signature: 2:1 read:write
DRAM only bandwidth (GBps): 298.8
DRAM + CXL (default interleave) (GBps): 113.04
DRAM + CXL (weighted interleave)(GBps): 412.5
Gain over DRAM only: 1.38x
Gain over default interleave: 2.64x
Workload: W5
Data Signature: 1:1 read:write
DRAM only bandwidth (GBps): 273.2
DRAM + CXL (default interleave) (GBps): 117.23
DRAM + CXL (weighted interleave)(GBps): 382.7
Gain over DRAM only: 1.4x
Gain over default interleave: 2.26x
=====================================================================
Performance test - Stream
From - Gregory Price <gregory.price@memverge.com>
Hardware: Single socket, single CXL expander
numactl extension: https://github.com/gmprice/numactl/tree/weighted_interleave_master
Summary: 64 threads, ~18GB workload, 3GB per array, executed 100 times
Default interleave : -78% (slower than DRAM)
Global weighting : -6% to +4% (workload dependant)
mbind2 weights : +2.5% to +4% (consistently better than DRAM)
dram only:
numactl --cpunodebind=1 --membind=1 ./stream_c.exe --ntimes 100 --array-size 400M --malloc
Function Direction BestRateMBs AvgTime MinTime MaxTime
Copy: 0->0 200923.2 0.032662 0.031853 0.033301
Scale: 0->0 202123.0 0.032526 0.031664 0.032970
Add: 0->0 208873.2 0.047322 0.045961 0.047884
Triad: 0->0 208523.8 0.047262 0.046038 0.048414
CXL-only:
numactl --cpunodebind=1 -w --membind=2 ./stream_c.exe --ntimes 100 --array-size 400M --malloc
Copy: 0->0 22209.7 0.288661 0.288162 0.289342
Scale: 0->0 22288.2 0.287549 0.287147 0.288291
Add: 0->0 24419.1 0.393372 0.393135 0.393735
Triad: 0->0 24484.6 0.392337 0.392083 0.394331
Based on the above, the optimal weights are ~9:1
echo 9 > /sys/kernel/mm/mempolicy/weighted_interleave/node1
echo 1 > /sys/kernel/mm/mempolicy/weighted_interleave/node2
default interleave:
numactl --cpunodebind=1 --interleave=1,2 ./stream_c.exe --ntimes 100 --array-size 400M --malloc
Copy: 0->0 44666.2 0.143671 0.143285 0.144174
Scale: 0->0 44781.6 0.143256 0.142916 0.143713
Add: 0->0 48600.7 0.197719 0.197528 0.197858
Triad: 0->0 48727.5 0.197204 0.197014 0.197439
global weighted interleave:
numactl --cpunodebind=1 -w --interleave=1,2 ./stream_c.exe --ntimes 100 --array-size 400M --malloc
Copy: 0->0 190085.9 0.034289 0.033669 0.034645
Scale: 0->0 207677.4 0.031909 0.030817 0.033061
Add: 0->0 202036.8 0.048737 0.047516 0.053409
Triad: 0->0 217671.5 0.045819 0.044103 0.046755
targted regions w/ global weights (modified stream to mbind2 malloc'd regions))
numactl --cpunodebind=1 --membind=1 ./stream_c.exe -b --ntimes 100 --array-size 400M --malloc
Copy: 0->0 205827.0 0.031445 0.031094 0.031984
Scale: 0->0 208171.8 0.031320 0.030744 0.032505
Add: 0->0 217352.0 0.045087 0.044168 0.046515
Triad: 0->0 216884.8 0.045062 0.044263 0.046982
=====================================================================
Performance tests - XSBench
From - Hyeongtak Ji <hyeongtak.ji@sk.com>
Hardware: Single socket, Single CXL memory Expander
NUMA node 0: 56 logical cores, 128 GB memory
NUMA node 2: 96 GB CXL memory
Threads: 56
Lookups: 170,000,000
Summary: +19% over DRAM. +47% over default interleave.
Performance tests - XSBench
1. dram only
$ numactl -m 0 ./XSBench -s XL –p 5000000
Runtime: 36.235 seconds
Lookups/s: 4,691,618
2. default interleave
$ numactl –i 0,2 ./XSBench –s XL –p 5000000
Runtime: 55.243 seconds
Lookups/s: 3,077,293
3. weighted interleave
numactl –w –i 0,2 ./XSBench –s XL –p 5000000
Runtime: 29.262 seconds
Lookups/s: 5,809,513
=====================================================================
LTP Tests: https://github.com/gmprice/ltp/tree/mempolicy2
= Existing tests
set_mempolicy, get_mempolicy, mbind
MPOL_WEIGHTED_INTERLEAVE added manually to test basic functionality but
did not adjust tests for weighting. Basically the weights were set to 1,
which is the default, and it should behave the same as MPOL_INTERLEAVE if
logic is correct.
== set_mempolicy01 : passed 18, failed 0
== set_mempolicy02 : passed 10, failed 0
== set_mempolicy03 : passed 64, failed 0
== set_mempolicy04 : passed 32, failed 0
== set_mempolicy05 - n/a on non-x86
== set_mempolicy06 : passed 10, failed 0
this is set_mempolicy02 + MPOL_WEIGHTED_INTERLEAVE
== set_mempolicy07 : passed 32, failed 0
set_mempolicy04 + MPOL_WEIGHTED_INTERLEAVE
== get_mempolicy01 : passed 12, failed 0
change: added MPOL_WEIGHTED_INTERLEAVE
== get_mempolicy02 : passed 2, failed 0
== mbind01 : passed 15, failed 0
added MPOL_WEIGHTED_INTERLEAVE
== mbind02 : passed 4, failed 0
added MPOL_WEIGHTED_INTERLEAVE
== mbind03 : passed 16, failed 0
added MPOL_WEIGHTED_INTERLEAVE
== mbind04 : passed 48, failed 0
added MPOL_WEIGHTED_INTERLEAVE
=====================================================================
numactl (set_mempolicy) w/ global weighting test
numactl fork: https://github.com/gmprice/numactl/tree/weighted_interleave_master
command: numactl -w --interleave=0,1 ./eatmem
result (weights 1:1):
0176a000 weighted interleave:0-1 heap anon=65793 dirty=65793 active=0 N0=32897 N1=32896 kernelpagesize_kB=4
7fceeb9ff000 weighted interleave:0-1 anon=65537 dirty=65537 active=0 N0=32768 N1=32769 kernelpagesize_kB=4
50% distribution is correct
result (weights 5:1):
01b14000 weighted interleave:0-1 heap anon=65793 dirty=65793 active=0 N0=54828 N1=10965 kernelpagesize_kB=4
7f47a1dff000 weighted interleave:0-1 anon=65537 dirty=65537 active=0 N0=54614 N1=10923 kernelpagesize_kB=4
16.666% distribution is correct
result (weights 1:5):
01f07000 weighted interleave:0-1 heap anon=65793 dirty=65793 active=0 N0=10966 N1=54827 kernelpagesize_kB=4
7f17b1dff000 weighted interleave:0-1 anon=65537 dirty=65537 active=0 N0=10923 N1=54614 kernelpagesize_kB=4
16.666% distribution is correct
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main (void)
{
char* mem = malloc(1024*1024*256);
memset(mem, 1, 1024*1024*256);
for (int i = 0; i < ((1024*1024*256)/4096); i++)
{
mem = malloc(4096);
mem[0] = 1;
}
printf("done\n");
getchar();
return 0;
}
This patch (of 4):
This patch provides a way to set interleave weight information under sysfs
at /sys/kernel/mm/mempolicy/weighted_interleave/nodeN
The sysfs structure is designed as follows.
$ tree /sys/kernel/mm/mempolicy/
/sys/kernel/mm/mempolicy/ [1]
└── weighted_interleave [2]
├── node0 [3]
└── node1
Each file above can be explained as follows.
[1] mm/mempolicy: configuration interface for mempolicy subsystem
[2] weighted_interleave/: config interface for weighted interleave policy
[3] weighted_interleave/nodeN: weight for nodeN
If a node value is set to `0`, the system-default value will be used.
As of this patch, the system-default for all nodes is always 1.
Link: https://lkml.kernel.org/r/20240202170238.90004-1-gregory.price@memverge.com
Link: https://lkml.kernel.org/r/20240202170238.90004-2-gregory.price@memverge.com
Suggested-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Rakie Kim <rakie.kim@sk.com>
Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
Co-developed-by: Gregory Price <gregory.price@memverge.com>
Signed-off-by: Gregory Price <gregory.price@memverge.com>
Co-developed-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Signed-off-by: Hyeongtak Ji <hyeongtak.ji@sk.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Gregory Price <gourry.memverge@gmail.com>
Cc: Hasan Al Maruf <Hasan.Maruf@amd.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Srinivasulu Thanneeru <sthanneeru.opensrc@micron.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Use SZ_{8K, 128K} helper macro instead of the number in init_user_reserve
and reserve_mem_notifier. This is more readable.
Link: https://lkml.kernel.org/r/20240131031913.2058597-1-yajun.deng@linux.dev
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kernel builders could silently enable CONFIG_DAMON_DBGFS_DEPRECATED.
Users who manually check the files under the DAMON debugfs directory could
notice the deprecation owing to the 'DEPRECATED' DAMON debugfs file, but
there could be users who doesn't manually check the files.
Make the deprecation cannot be ignored in the case by renaming
'monitor_on' file, which is essential for real use of DAMON on runtime, to
'monitor_on_DEPRECATED'. Still users who control DAMON via only
user-space tool could ignore the deprecation, but that's what the tool
developers should take care of. DAMON user-space tool, damo, has also
made a change[1] for the purpose.
[1] commit 935dae76f2aee ("_damon_args: Rename --damon_interface to
--damon_interface_DEPRECATED") of https://github.com/awslabs/damo
Link: https://lkml.kernel.org/r/20240130013549.89538-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
DAMON debugfs interface deprecation message is written twice, once for the
warning, and again for DEPRECATED file's read output. De-duplicate those
by defining the message as a macro and reuse.
[akpm@linux-foundation.org: s/comnst/const/]
Link: https://lkml.kernel.org/r/20240130013549.89538-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Alex Shi <alexs@kernel.org>
Cc: Hu Haowen <2023002089@link.tyut.edu.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yanteng Si <siyanteng@loongson.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
