Hi Barry, Thanks for taking time to review! On Mon, Jul 1, 2024 at 8:02 AM Barry Song <21cnbao@xxxxxxxxx> wrote: > > On Sat, Jun 29, 2024 at 1:09 AM Lance Yang <ioworker0@xxxxxxxxx> wrote: > > > > Currently, the split counters in THP statistics no longer include > > PTE-mapped mTHP. Therefore, we propose introducing per-order mTHP split > > counters to monitor the frequency of mTHP splits. This will help developers > > better analyze and optimize system performance. > > > > /sys/kernel/mm/transparent_hugepage/hugepages-<size>/stats > > split > > split_failed > > split_deferred > > > > Signed-off-by: Mingzhe Yang <mingzhe.yang@xxxxxx> > > Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx> > > Personally, I'm not convinced that using a temporary variable order > makes the code > more readable. Functions like folio_test_pmd_mappable() seem more readable to Agreed. Using functions like folio_test_pmd_mappable() is more readable for THP checks. > me. In any case, it's a minor issue. I'd like to hear other opinions as well ;) > > Acked-by: Barry Song <baohua@xxxxxxxxxx> Thanks again for your time! Lance > > > --- > > include/linux/huge_mm.h | 3 +++ > > mm/huge_memory.c | 19 ++++++++++++++----- > > 2 files changed, 17 insertions(+), 5 deletions(-) > > > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > > index 212cca384d7e..cee3c5da8f0e 100644 > > --- a/include/linux/huge_mm.h > > +++ b/include/linux/huge_mm.h > > @@ -284,6 +284,9 @@ enum mthp_stat_item { > > MTHP_STAT_FILE_ALLOC, > > MTHP_STAT_FILE_FALLBACK, > > MTHP_STAT_FILE_FALLBACK_CHARGE, > > + MTHP_STAT_SPLIT, > > + MTHP_STAT_SPLIT_FAILED, > > + MTHP_STAT_SPLIT_DEFERRED, > > __MTHP_STAT_COUNT > > }; > > > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > > index c7ce28f6b7f3..a633206375af 100644 > > --- a/mm/huge_memory.c > > +++ b/mm/huge_memory.c > > @@ -559,6 +559,9 @@ DEFINE_MTHP_STAT_ATTR(swpout_fallback, MTHP_STAT_SWPOUT_FALLBACK); > > DEFINE_MTHP_STAT_ATTR(file_alloc, MTHP_STAT_FILE_ALLOC); > > DEFINE_MTHP_STAT_ATTR(file_fallback, MTHP_STAT_FILE_FALLBACK); > > DEFINE_MTHP_STAT_ATTR(file_fallback_charge, MTHP_STAT_FILE_FALLBACK_CHARGE); > > +DEFINE_MTHP_STAT_ATTR(split, MTHP_STAT_SPLIT); > > +DEFINE_MTHP_STAT_ATTR(split_failed, MTHP_STAT_SPLIT_FAILED); > > +DEFINE_MTHP_STAT_ATTR(split_deferred, MTHP_STAT_SPLIT_DEFERRED); > > > > static struct attribute *stats_attrs[] = { > > &anon_fault_alloc_attr.attr, > > @@ -569,6 +572,9 @@ static struct attribute *stats_attrs[] = { > > &file_alloc_attr.attr, > > &file_fallback_attr.attr, > > &file_fallback_charge_attr.attr, > > + &split_attr.attr, > > + &split_failed_attr.attr, > > + &split_deferred_attr.attr, > > NULL, > > }; > > > > @@ -3068,7 +3074,7 @@ 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; > > @@ -3076,7 +3082,7 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, > > VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); > > VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); > > > > - if (new_order >= folio_order(folio)) > > + if (new_order >= order) > > return -EINVAL; > > > > if (folio_test_anon(folio)) { > > @@ -3253,8 +3259,9 @@ 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 : MTHP_STAT_SPLIT_FAILED); > > return ret; > > } > > > > @@ -3278,13 +3285,14 @@ void deferred_split_folio(struct folio *folio) > > #ifdef CONFIG_MEMCG > > struct mem_cgroup *memcg = folio_memcg(folio); > > #endif > > + int order = folio_order(folio); > > unsigned long flags; > > > > /* > > * 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; > > > > /* > > @@ -3305,8 +3313,9 @@ 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_SPLIT_DEFERRED); > > list_add_tail(&folio->_deferred_list, &ds_queue->split_queue); > > ds_queue->split_queue_len++; > > #ifdef CONFIG_MEMCG > > -- > > 2.45.2 > >