Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Thu, 25 Apr 2024 01:12:49 +0800 | Subject | Re: [PATCH 1/2] mm: add per-order mTHP split counters | From | Bang Li <> |
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Hey Lance,
On 2024/4/24 21:51, Lance Yang wrote:
> At present, the split counters in THP statistics no longer include > PTE-mapped mTHP. Therefore, this commit introduces per-order mTHP split > counters to monitor the frequency of mTHP splits. This will assist > developers in better analyzing and optimizing system performance. > > /sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats > split_page > split_page_failed > deferred_split_page > > Signed-off-by: Lance Yang <ioworker0@gmail.com> > --- > include/linux/huge_mm.h | 3 +++ > mm/huge_memory.c | 14 ++++++++++++-- > 2 files changed, 15 insertions(+), 2 deletions(-) > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index 56c7ea73090b..7b9c6590e1f7 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -272,6 +272,9 @@ enum mthp_stat_item { > MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE, > MTHP_STAT_ANON_SWPOUT, > MTHP_STAT_ANON_SWPOUT_FALLBACK, > + MTHP_STAT_SPLIT_PAGE, > + MTHP_STAT_SPLIT_PAGE_FAILED, > + MTHP_STAT_DEFERRED_SPLIT_PAGE, > __MTHP_STAT_COUNT > }; > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 055df5aac7c3..52db888e47a6 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -557,6 +557,9 @@ DEFINE_MTHP_STAT_ATTR(anon_fault_fallback, MTHP_STAT_ANON_FAULT_FALLBACK); > DEFINE_MTHP_STAT_ATTR(anon_fault_fallback_charge, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE); > DEFINE_MTHP_STAT_ATTR(anon_swpout, MTHP_STAT_ANON_SWPOUT); > DEFINE_MTHP_STAT_ATTR(anon_swpout_fallback, MTHP_STAT_ANON_SWPOUT_FALLBACK); > +DEFINE_MTHP_STAT_ATTR(split_page, MTHP_STAT_SPLIT_PAGE); > +DEFINE_MTHP_STAT_ATTR(split_page_failed, MTHP_STAT_SPLIT_PAGE_FAILED); > +DEFINE_MTHP_STAT_ATTR(deferred_split_page, MTHP_STAT_DEFERRED_SPLIT_PAGE); > > static struct attribute *stats_attrs[] = { > &anon_fault_alloc_attr.attr, > @@ -564,6 +567,9 @@ static struct attribute *stats_attrs[] = { > &anon_fault_fallback_charge_attr.attr, > &anon_swpout_attr.attr, > &anon_swpout_fallback_attr.attr, > + &split_page_attr.attr, > + &split_page_failed_attr.attr, > + &deferred_split_page_attr.attr, > NULL, > }; > > @@ -3083,7 +3089,7 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, > XA_STATE_ORDER(xas, &folio->mapping->i_pages, folio->index, new_order); > struct anon_vma *anon_vma = NULL; > struct address_space *mapping = NULL; > - bool is_thp = folio_test_pmd_mappable(folio); > + int order = folio_order(folio); > int extra_pins, ret; > pgoff_t end; > bool is_hzp; > @@ -3262,8 +3268,10 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, > i_mmap_unlock_read(mapping); > out: > xas_destroy(&xas); > - if (is_thp) > + if (order >= HPAGE_PMD_ORDER) > count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED); > + count_mthp_stat(order, !ret ? MTHP_STAT_SPLIT_PAGE : > + MTHP_STAT_SPLIT_PAGE_FAILED); > return ret; > } > > @@ -3327,6 +3335,8 @@ void deferred_split_folio(struct folio *folio) > if (list_empty(&folio->_deferred_list)) { > if (folio_test_pmd_mappable(folio)) > count_vm_event(THP_DEFERRED_SPLIT_PAGE); > + count_mthp_stat(folio_order(folio), > + MTHP_STAT_DEFERRED_SPLIT_PAGE); > list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); > ds_queue->split_queue_len++; > #ifdef CONFIG_MEMCG
My opinion can be ignored :). Would it be better to modify the deferred_split_folio function as follows? I'm not sure.
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 055df5aac7c3..e8562e8630b1 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3299,12 +3299,13 @@ void deferred_split_folio(struct folio *folio) struct mem_cgroup *memcg = folio_memcg(folio); #endif unsigned long flags; + int order = folio_order(folio); /* * Order 1 folios have no space for a deferred list, but we also * won't waste much memory by not adding them to the deferred list. */ - if (folio_order(folio) <= 1) + if (order <= 1) return; /* @@ -3325,8 +3326,9 @@ void deferred_split_folio(struct folio *folio) spin_lock_irqsave(&ds_queue->split_queue_lock, flags); if (list_empty(&folio->_deferred_list)) { - if (folio_test_pmd_mappable(folio)) + if (order >= HPAGE_PMD_ORDER) count_vm_event(THP_DEFERRED_SPLIT_PAGE); + count_mthp_stat(order, MTHP_STAT_DEFERRED_SPLIT_PAGE); list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); ds_queue->split_queue_len++; #ifdef CONFIG_MEMCG thanks, bang
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