<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/net/core/page_pool.c, branch v6.5</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>page_pool: fix inconsistency for page_pool_ring_[un]lock()</title>
<updated>2023-05-24T03:25:13+00:00</updated>
<author>
<name>Yunsheng Lin</name>
<email>linyunsheng@huawei.com</email>
</author>
<published>2023-05-22T03:17:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=368d3cb406cdd074d1df2ad9ec06d1bfcb664882'/>
<id>368d3cb406cdd074d1df2ad9ec06d1bfcb664882</id>
<content type='text'>
page_pool_ring_[un]lock() use in_softirq() to decide which
spin lock variant to use, and when they are called in the
context with in_softirq() being false, spin_lock_bh() is
called in page_pool_ring_lock() while spin_unlock() is
called in page_pool_ring_unlock(), because spin_lock_bh()
has disabled the softirq in page_pool_ring_lock(), which
causes inconsistency for spin lock pair calling.

This patch fixes it by returning in_softirq state from
page_pool_producer_lock(), and use it to decide which
spin lock variant to use in page_pool_producer_unlock().

As pool-&gt;ring has both producer and consumer lock, so
rename it to page_pool_producer_[un]lock() to reflect
the actual usage. Also move them to page_pool.c as they
are only used there, and remove the 'inline' as the
compiler may have better idea to do inlining or not.

Fixes: 7886244736a4 ("net: page_pool: Add bulk support for ptr_ring")
Signed-off-by: Yunsheng Lin &lt;linyunsheng@huawei.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Link: https://lore.kernel.org/r/20230522031714.5089-1-linyunsheng@huawei.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
page_pool_ring_[un]lock() use in_softirq() to decide which
spin lock variant to use, and when they are called in the
context with in_softirq() being false, spin_lock_bh() is
called in page_pool_ring_lock() while spin_unlock() is
called in page_pool_ring_unlock(), because spin_lock_bh()
has disabled the softirq in page_pool_ring_lock(), which
causes inconsistency for spin lock pair calling.

This patch fixes it by returning in_softirq state from
page_pool_producer_lock(), and use it to decide which
spin lock variant to use in page_pool_producer_unlock().

As pool-&gt;ring has both producer and consumer lock, so
rename it to page_pool_producer_[un]lock() to reflect
the actual usage. Also move them to page_pool.c as they
are only used there, and remove the 'inline' as the
compiler may have better idea to do inlining or not.

Fixes: 7886244736a4 ("net: page_pool: Add bulk support for ptr_ring")
Signed-off-by: Yunsheng Lin &lt;linyunsheng@huawei.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Link: https://lore.kernel.org/r/20230522031714.5089-1-linyunsheng@huawei.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>page_pool: unlink from napi during destroy</title>
<updated>2023-04-21T02:13:37+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2023-04-19T18:20:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=dd64b232deb8d48812a2ea739d1fedaeaffb59ed'/>
<id>dd64b232deb8d48812a2ea739d1fedaeaffb59ed</id>
<content type='text'>
Jesper points out that we must prevent recycling into cache
after page_pool_destroy() is called, because page_pool_destroy()
is not synchronized with recycling (some pages may still be
outstanding when destroy() gets called).

I assumed this will not happen because NAPI can't be scheduled
if its page pool is being destroyed. But I missed the fact that
NAPI may get reused. For instance when user changes ring configuration
driver may allocate a new page pool, stop NAPI, swap, start NAPI,
and then destroy the old pool. The NAPI is running so old page
pool will think it can recycle to the cache, but the consumer
at that point is the destroy() path, not NAPI.

To avoid extra synchronization let the drivers do "unlinking"
during the "swap" stage while NAPI is indeed disabled.

Fixes: 8c48eea3adf3 ("page_pool: allow caching from safely localized NAPI")
Reported-by: Jesper Dangaard Brouer &lt;jbrouer@redhat.com&gt;
Link: https://lore.kernel.org/all/e8df2654-6a5b-3c92-489d-2fe5e444135f@redhat.com/
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Link: https://lore.kernel.org/r/20230419182006.719923-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Jesper points out that we must prevent recycling into cache
after page_pool_destroy() is called, because page_pool_destroy()
is not synchronized with recycling (some pages may still be
outstanding when destroy() gets called).

I assumed this will not happen because NAPI can't be scheduled
if its page pool is being destroyed. But I missed the fact that
NAPI may get reused. For instance when user changes ring configuration
driver may allocate a new page pool, stop NAPI, swap, start NAPI,
and then destroy the old pool. The NAPI is running so old page
pool will think it can recycle to the cache, but the consumer
at that point is the destroy() path, not NAPI.

To avoid extra synchronization let the drivers do "unlinking"
during the "swap" stage while NAPI is indeed disabled.

Fixes: 8c48eea3adf3 ("page_pool: allow caching from safely localized NAPI")
Reported-by: Jesper Dangaard Brouer &lt;jbrouer@redhat.com&gt;
Link: https://lore.kernel.org/all/e8df2654-6a5b-3c92-489d-2fe5e444135f@redhat.com/
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Link: https://lore.kernel.org/r/20230419182006.719923-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>page_pool: add DMA_ATTR_WEAK_ORDERING on all mappings</title>
<updated>2023-04-19T18:28:15+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2023-04-17T15:28:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8e4c62c7d980eaf0f64c1c0ef0c80f5685af0fb6'/>
<id>8e4c62c7d980eaf0f64c1c0ef0c80f5685af0fb6</id>
<content type='text'>
Commit c519fe9a4f0d ("bnxt: add dma mapping attributes") added
DMA_ATTR_WEAK_ORDERING to DMA attrs on bnxt. It has since spread
to a few more drivers (possibly as a copy'n'paste).

DMA_ATTR_WEAK_ORDERING only seems to matter on Sparc and PowerPC/cell,
the rarity of these platforms is likely why we never bothered adding
the attribute in the page pool, even though it should be safe to add.

To make the page pool migration in drivers which set this flag less
of a risk (of regressing the precious sparc database workloads or
whatever needed this) let's add DMA_ATTR_WEAK_ORDERING on all
page pool DMA mappings.

We could make this a driver opt-in but frankly I don't think it's
worth complicating the API. I can't think of a reason why device
accesses to packet memory would have to be ordered.

Acked-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Acked-by: Somnath Kotur &lt;somnath.kotur@broadcom.com&gt;
Reviewed-by: Alexander Lobakin &lt;aleksander.lobakin@intel.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Link: https://lore.kernel.org/r/20230417152805.331865-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit c519fe9a4f0d ("bnxt: add dma mapping attributes") added
DMA_ATTR_WEAK_ORDERING to DMA attrs on bnxt. It has since spread
to a few more drivers (possibly as a copy'n'paste).

DMA_ATTR_WEAK_ORDERING only seems to matter on Sparc and PowerPC/cell,
the rarity of these platforms is likely why we never bothered adding
the attribute in the page pool, even though it should be safe to add.

To make the page pool migration in drivers which set this flag less
of a risk (of regressing the precious sparc database workloads or
whatever needed this) let's add DMA_ATTR_WEAK_ORDERING on all
page pool DMA mappings.

We could make this a driver opt-in but frankly I don't think it's
worth complicating the API. I can't think of a reason why device
accesses to packet memory would have to be ordered.

Acked-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Acked-by: Somnath Kotur &lt;somnath.kotur@broadcom.com&gt;
Reviewed-by: Alexander Lobakin &lt;aleksander.lobakin@intel.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Link: https://lore.kernel.org/r/20230417152805.331865-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>page_pool: allow caching from safely localized NAPI</title>
<updated>2023-04-15T01:56:12+00:00</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2023-04-13T04:26:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8c48eea3adf3119e0a3fc57bd31f6966f26ee784'/>
<id>8c48eea3adf3119e0a3fc57bd31f6966f26ee784</id>
<content type='text'>
Recent patches to mlx5 mentioned a regression when moving from
driver local page pool to only using the generic page pool code.
Page pool has two recycling paths (1) direct one, which runs in
safe NAPI context (basically consumer context, so producing
can be lockless); and (2) via a ptr_ring, which takes a spin
lock because the freeing can happen from any CPU; producer
and consumer may run concurrently.

Since the page pool code was added, Eric introduced a revised version
of deferred skb freeing. TCP skbs are now usually returned to the CPU
which allocated them, and freed in softirq context. This places the
freeing (producing of pages back to the pool) enticingly close to
the allocation (consumer).

If we can prove that we're freeing in the same softirq context in which
the consumer NAPI will run - lockless use of the cache is perfectly fine,
no need for the lock.

Let drivers link the page pool to a NAPI instance. If the NAPI instance
is scheduled on the same CPU on which we're freeing - place the pages
in the direct cache.

With that and patched bnxt (XDP enabled to engage the page pool, sigh,
bnxt really needs page pool work :() I see a 2.6% perf boost with
a TCP stream test (app on a different physical core than softirq).

The CPU use of relevant functions decreases as expected:

  page_pool_refill_alloc_cache   1.17% -&gt; 0%
  _raw_spin_lock                 2.41% -&gt; 0.98%

Only consider lockless path to be safe when NAPI is scheduled
- in practice this should cover majority if not all of steady state
workloads. It's usually the NAPI kicking in that causes the skb flush.

The main case we'll miss out on is when application runs on the same
CPU as NAPI. In that case we don't use the deferred skb free path.

Reviewed-by: Tariq Toukan &lt;tariqt@nvidia.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Tested-by: Dragos Tatulea &lt;dtatulea@nvidia.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Recent patches to mlx5 mentioned a regression when moving from
driver local page pool to only using the generic page pool code.
Page pool has two recycling paths (1) direct one, which runs in
safe NAPI context (basically consumer context, so producing
can be lockless); and (2) via a ptr_ring, which takes a spin
lock because the freeing can happen from any CPU; producer
and consumer may run concurrently.

Since the page pool code was added, Eric introduced a revised version
of deferred skb freeing. TCP skbs are now usually returned to the CPU
which allocated them, and freed in softirq context. This places the
freeing (producing of pages back to the pool) enticingly close to
the allocation (consumer).

If we can prove that we're freeing in the same softirq context in which
the consumer NAPI will run - lockless use of the cache is perfectly fine,
no need for the lock.

Let drivers link the page pool to a NAPI instance. If the NAPI instance
is scheduled on the same CPU on which we're freeing - place the pages
in the direct cache.

With that and patched bnxt (XDP enabled to engage the page pool, sigh,
bnxt really needs page pool work :() I see a 2.6% perf boost with
a TCP stream test (app on a different physical core than softirq).

The CPU use of relevant functions decreases as expected:

  page_pool_refill_alloc_cache   1.17% -&gt; 0%
  _raw_spin_lock                 2.41% -&gt; 0.98%

Only consider lockless path to be safe when NAPI is scheduled
- in practice this should cover majority if not all of steady state
workloads. It's usually the NAPI kicking in that causes the skb flush.

The main case we'll miss out on is when application runs on the same
CPU as NAPI. In that case we don't use the deferred skb free path.

Reviewed-by: Tariq Toukan &lt;tariqt@nvidia.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Tested-by: Dragos Tatulea &lt;dtatulea@nvidia.com&gt;
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: page_pool: use in_softirq() instead</title>
<updated>2023-02-06T09:15:22+00:00</updated>
<author>
<name>Qingfang DENG</name>
<email>qingfang.deng@siflower.com.cn</email>
</author>
<published>2023-02-03T01:16:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=542bcea4be866b14b3a5c8e90773329066656c43'/>
<id>542bcea4be866b14b3a5c8e90773329066656c43</id>
<content type='text'>
We use BH context only for synchronization, so we don't care if it's
actually serving softirq or not.

As a side node, in case of threaded NAPI, in_serving_softirq() will
return false because it's in process context with BH off, making
page_pool_recycle_in_cache() unreachable.

Signed-off-by: Qingfang DENG &lt;qingfang.deng@siflower.com.cn&gt;
Tested-by: Felix Fietkau &lt;nbd@nbd.name&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We use BH context only for synchronization, so we don't care if it's
actually serving softirq or not.

As a side node, in case of threaded NAPI, in_serving_softirq() will
return false because it's in process context with BH off, making
page_pool_recycle_in_cache() unreachable.

Signed-off-by: Qingfang DENG &lt;qingfang.deng@siflower.com.cn&gt;
Tested-by: Felix Fietkau &lt;nbd@nbd.name&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2022-08-05T23:32:45+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-08-05T23:32:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6614a3c3164a5df2b54abb0b3559f51041cf705b'/>
<id>6614a3c3164a5df2b54abb0b3559f51041cf705b</id>
<content type='text'>
Pull MM updates from Andrew Morton:
 "Most of the MM queue. A few things are still pending.

  Liam's maple tree rework didn't make it. This has resulted in a few
  other minor patch series being held over for next time.

  Multi-gen LRU still isn't merged as we were waiting for mapletree to
  stabilize. The current plan is to merge MGLRU into -mm soon and to
  later reintroduce mapletree, with a view to hopefully getting both
  into 6.1-rc1.

  Summary:

   - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
     Lin, Yang Shi, Anshuman Khandual and Mike Rapoport

   - Some kmemleak fixes from Patrick Wang and Waiman Long

   - DAMON updates from SeongJae Park

   - memcg debug/visibility work from Roman Gushchin

   - vmalloc speedup from Uladzislau Rezki

   - more folio conversion work from Matthew Wilcox

   - enhancements for coherent device memory mapping from Alex Sierra

   - addition of shared pages tracking and CoW support for fsdax, from
     Shiyang Ruan

   - hugetlb optimizations from Mike Kravetz

   - Mel Gorman has contributed some pagealloc changes to improve
     latency and realtime behaviour.

   - mprotect soft-dirty checking has been improved by Peter Xu

   - Many other singleton patches all over the place"

 [ XFS merge from hell as per Darrick Wong in

   https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]

* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
  tools/testing/selftests/vm/hmm-tests.c: fix build
  mm: Kconfig: fix typo
  mm: memory-failure: convert to pr_fmt()
  mm: use is_zone_movable_page() helper
  hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
  hugetlbfs: cleanup some comments in inode.c
  hugetlbfs: remove unneeded header file
  hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
  hugetlbfs: use helper macro SZ_1{K,M}
  mm: cleanup is_highmem()
  mm/hmm: add a test for cross device private faults
  selftests: add soft-dirty into run_vmtests.sh
  selftests: soft-dirty: add test for mprotect
  mm/mprotect: fix soft-dirty check in can_change_pte_writable()
  mm: memcontrol: fix potential oom_lock recursion deadlock
  mm/gup.c: fix formatting in check_and_migrate_movable_page()
  xfs: fail dax mount if reflink is enabled on a partition
  mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
  userfaultfd: don't fail on unrecognized features
  hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull MM updates from Andrew Morton:
 "Most of the MM queue. A few things are still pending.

  Liam's maple tree rework didn't make it. This has resulted in a few
  other minor patch series being held over for next time.

  Multi-gen LRU still isn't merged as we were waiting for mapletree to
  stabilize. The current plan is to merge MGLRU into -mm soon and to
  later reintroduce mapletree, with a view to hopefully getting both
  into 6.1-rc1.

  Summary:

   - The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
     Lin, Yang Shi, Anshuman Khandual and Mike Rapoport

   - Some kmemleak fixes from Patrick Wang and Waiman Long

   - DAMON updates from SeongJae Park

   - memcg debug/visibility work from Roman Gushchin

   - vmalloc speedup from Uladzislau Rezki

   - more folio conversion work from Matthew Wilcox

   - enhancements for coherent device memory mapping from Alex Sierra

   - addition of shared pages tracking and CoW support for fsdax, from
     Shiyang Ruan

   - hugetlb optimizations from Mike Kravetz

   - Mel Gorman has contributed some pagealloc changes to improve
     latency and realtime behaviour.

   - mprotect soft-dirty checking has been improved by Peter Xu

   - Many other singleton patches all over the place"

 [ XFS merge from hell as per Darrick Wong in

   https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]

* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
  tools/testing/selftests/vm/hmm-tests.c: fix build
  mm: Kconfig: fix typo
  mm: memory-failure: convert to pr_fmt()
  mm: use is_zone_movable_page() helper
  hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
  hugetlbfs: cleanup some comments in inode.c
  hugetlbfs: remove unneeded header file
  hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
  hugetlbfs: use helper macro SZ_1{K,M}
  mm: cleanup is_highmem()
  mm/hmm: add a test for cross device private faults
  selftests: add soft-dirty into run_vmtests.sh
  selftests: soft-dirty: add test for mprotect
  mm/mprotect: fix soft-dirty check in can_change_pte_writable()
  mm: memcontrol: fix potential oom_lock recursion deadlock
  mm/gup.c: fix formatting in check_and_migrate_movable_page()
  xfs: fail dax mount if reflink is enabled on a partition
  mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
  userfaultfd: don't fail on unrecognized features
  hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>net: page_pool: optimize page pool page allocation in NUMA scenario</title>
<updated>2022-07-08T00:03:16+00:00</updated>
<author>
<name>Jie Wang</name>
<email>wangjie125@huawei.com</email>
</author>
<published>2022-07-05T11:35:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=d810d367ec40a1031173a447bd0146cf48e98733'/>
<id>d810d367ec40a1031173a447bd0146cf48e98733</id>
<content type='text'>
Currently NIC packet receiving performance based on page pool deteriorates
occasionally. To analysis the causes of this problem page allocation stats
are collected. Here are the stats when NIC rx performance deteriorates:

bandwidth(Gbits/s)		16.8		6.91
rx_pp_alloc_fast		13794308	21141869
rx_pp_alloc_slow		108625		166481
rx_pp_alloc_slow_h		0		0
rx_pp_alloc_empty		8192		8192
rx_pp_alloc_refill		0		0
rx_pp_alloc_waive		100433		158289
rx_pp_recycle_cached		0		0
rx_pp_recycle_cache_full	0		0
rx_pp_recycle_ring		362400		420281
rx_pp_recycle_ring_full		6064893		9709724
rx_pp_recycle_released_ref	0		0

The rx_pp_alloc_waive count indicates that a large number of pages' numa
node are inconsistent with the NIC device numa node. Therefore these pages
can't be reused by the page pool. As a result, many new pages would be
allocated by __page_pool_alloc_pages_slow which is time consuming. This
causes the NIC rx performance fluctuations.

The main reason of huge numa mismatch pages in page pool is that page pool
uses alloc_pages_bulk_array to allocate original pages. This function is
not suitable for page allocation in NUMA scenario. So this patch uses
alloc_pages_bulk_array_node which has a NUMA id input parameter to ensure
the NUMA consistent between NIC device and allocated pages.

Repeated NIC rx performance tests are performed 40 times. NIC rx bandwidth
is higher and more stable compared to the datas above. Here are three test
stats, the rx_pp_alloc_waive count is zero and rx_pp_alloc_slow which
indicates pages allocated from slow patch is relatively low.

bandwidth(Gbits/s)		93		93.9		93.8
rx_pp_alloc_fast		60066264	61266386	60938254
rx_pp_alloc_slow		16512		16517		16539
rx_pp_alloc_slow_ho		0		0		0
rx_pp_alloc_empty		16512		16517		16539
rx_pp_alloc_refill		473841		481910		481585
rx_pp_alloc_waive		0		0		0
rx_pp_recycle_cached		0		0		0
rx_pp_recycle_cache_full	0		0		0
rx_pp_recycle_ring		29754145	30358243	30194023
rx_pp_recycle_ring_full		0		0		0
rx_pp_recycle_released_ref	0		0		0

Signed-off-by: Jie Wang &lt;wangjie125@huawei.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Link: https://lore.kernel.org/r/20220705113515.54342-1-huangguangbin2@huawei.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently NIC packet receiving performance based on page pool deteriorates
occasionally. To analysis the causes of this problem page allocation stats
are collected. Here are the stats when NIC rx performance deteriorates:

bandwidth(Gbits/s)		16.8		6.91
rx_pp_alloc_fast		13794308	21141869
rx_pp_alloc_slow		108625		166481
rx_pp_alloc_slow_h		0		0
rx_pp_alloc_empty		8192		8192
rx_pp_alloc_refill		0		0
rx_pp_alloc_waive		100433		158289
rx_pp_recycle_cached		0		0
rx_pp_recycle_cache_full	0		0
rx_pp_recycle_ring		362400		420281
rx_pp_recycle_ring_full		6064893		9709724
rx_pp_recycle_released_ref	0		0

The rx_pp_alloc_waive count indicates that a large number of pages' numa
node are inconsistent with the NIC device numa node. Therefore these pages
can't be reused by the page pool. As a result, many new pages would be
allocated by __page_pool_alloc_pages_slow which is time consuming. This
causes the NIC rx performance fluctuations.

The main reason of huge numa mismatch pages in page pool is that page pool
uses alloc_pages_bulk_array to allocate original pages. This function is
not suitable for page allocation in NUMA scenario. So this patch uses
alloc_pages_bulk_array_node which has a NUMA id input parameter to ensure
the NUMA consistent between NIC device and allocated pages.

Repeated NIC rx performance tests are performed 40 times. NIC rx bandwidth
is higher and more stable compared to the datas above. Here are three test
stats, the rx_pp_alloc_waive count is zero and rx_pp_alloc_slow which
indicates pages allocated from slow patch is relatively low.

bandwidth(Gbits/s)		93		93.9		93.8
rx_pp_alloc_fast		60066264	61266386	60938254
rx_pp_alloc_slow		16512		16517		16539
rx_pp_alloc_slow_ho		0		0		0
rx_pp_alloc_empty		16512		16517		16539
rx_pp_alloc_refill		473841		481910		481585
rx_pp_alloc_waive		0		0		0
rx_pp_recycle_cached		0		0		0
rx_pp_recycle_cache_full	0		0		0
rx_pp_recycle_ring		29754145	30358243	30194023
rx_pp_recycle_ring_full		0		0		0
rx_pp_recycle_released_ref	0		0		0

Signed-off-by: Jie Wang &lt;wangjie125@huawei.com&gt;
Acked-by: Jesper Dangaard Brouer &lt;brouer@redhat.com&gt;
Acked-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Link: https://lore.kernel.org/r/20220705113515.54342-1-huangguangbin2@huawei.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/swap: convert __put_page() to __folio_put()</title>
<updated>2022-07-04T01:08:47+00:00</updated>
<author>
<name>Matthew Wilcox (Oracle)</name>
<email>willy@infradead.org</email>
</author>
<published>2022-06-17T17:50:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8d29c7036f5ff360ea1f51b9fed5d909be7c8094'/>
<id>8d29c7036f5ff360ea1f51b9fed5d909be7c8094</id>
<content type='text'>
Saves 11 bytes of text by removing a check of PageTail.

Link: https://lkml.kernel.org/r/20220617175020.717127-16-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Saves 11 bytes of text by removing a check of PageTail.

Link: https://lkml.kernel.org/r/20220617175020.717127-16-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) &lt;willy@infradead.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: page_pool: add page allocation stats for two fast page allocate path</title>
<updated>2022-05-13T10:28:55+00:00</updated>
<author>
<name>Jie Wang</name>
<email>wangjie125@huawei.com</email>
</author>
<published>2022-05-12T06:56:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0f6deac3a07958195173119627502350925dce78'/>
<id>0f6deac3a07958195173119627502350925dce78</id>
<content type='text'>
Currently If use page pool allocation stats to analysis a RX performance
degradation problem. These stats only count for pages allocate from
page_pool_alloc_pages. But nic drivers such as hns3 use
page_pool_dev_alloc_frag to allocate pages, so page stats in this API
should also be counted.

Signed-off-by: Jie Wang &lt;wangjie125@huawei.com&gt;
Signed-off-by: Guangbin Huang &lt;huangguangbin2@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Currently If use page pool allocation stats to analysis a RX performance
degradation problem. These stats only count for pages allocate from
page_pool_alloc_pages. But nic drivers such as hns3 use
page_pool_dev_alloc_frag to allocate pages, so page stats in this API
should also be counted.

Signed-off-by: Jie Wang &lt;wangjie125@huawei.com&gt;
Signed-off-by: Guangbin Huang &lt;huangguangbin2@huawei.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: page_pool: introduce ethtool stats</title>
<updated>2022-04-15T09:43:47+00:00</updated>
<author>
<name>Lorenzo Bianconi</name>
<email>lorenzo@kernel.org</email>
</author>
<published>2022-04-12T16:31:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f3c5264f452a5b0ac1de1f2f657efbabdea3c76a'/>
<id>f3c5264f452a5b0ac1de1f2f657efbabdea3c76a</id>
<content type='text'>
Introduce page_pool APIs to report stats through ethtool and reduce
duplicated code in each driver.

Signed-off-by: Lorenzo Bianconi &lt;lorenzo@kernel.org&gt;
Reviewed-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Reviewed-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Introduce page_pool APIs to report stats through ethtool and reduce
duplicated code in each driver.

Signed-off-by: Lorenzo Bianconi &lt;lorenzo@kernel.org&gt;
Reviewed-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Reviewed-by: Ilias Apalodimas &lt;ilias.apalodimas@linaro.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
