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Shutemov" , "Kirill A. Shutemov" , Mike Rapoport , Jeremy Cline , Linux Kernel Mailing List , Linux MM Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Mar 6, 2020 at 2:22 PM David Rientjes wrote: > > The thp_fault_fallback and thp_file_fallback vmstats are incremented if > either the hugepage allocation fails through the page allocator or the > hugepage charge fails through mem cgroup. > > This patch leaves this field untouched but adds two new fields, > thp_{fault,file}_fallback_charge, which is incremented only when the mem > cgroup charge fails. > > This distinguishes between attempted hugepage allocations that fail due to > fragmentation (or low memory conditions) and those that fail due to mem > cgroup limits. That can be used to determine the impact of fragmentation > on the system by excluding faults that failed due to memcg usage. Yes, it makes sense to me. Reviewed-by: Yang Shi > > Signed-off-by: David Rientjes > --- > Documentation/admin-guide/mm/transhuge.rst | 10 ++++++++++ > include/linux/vm_event_item.h | 3 +++ > mm/huge_memory.c | 2 ++ > mm/shmem.c | 4 +++- > mm/vmstat.c | 2 ++ > 5 files changed, 20 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst > --- a/Documentation/admin-guide/mm/transhuge.rst > +++ b/Documentation/admin-guide/mm/transhuge.rst > @@ -310,6 +310,11 @@ thp_fault_fallback > is incremented if a page fault fails to allocate > a huge page and instead falls back to using small pages. > > +thp_fault_fallback_charge > + is incremented if a page fault fails to charge a huge page and > + instead falls back to using small pages even though the > + allocation was successful. > + > thp_collapse_alloc_failed > is incremented if khugepaged found a range > of pages that should be collapsed into one huge page but failed > @@ -323,6 +328,11 @@ thp_file_fallback > is incremented if a file huge page is attempted to be allocated > but fails and instead falls back to using small pages. > > +thp_file_fallback_charge > + is incremented if a file huge page cannot be charged and instead > + falls back to using small pages even though the allocation was > + successful. > + > thp_file_mapped > is incremented every time a file huge page is mapped into > user address space. > diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h > --- a/include/linux/vm_event_item.h > +++ b/include/linux/vm_event_item.h > @@ -73,10 +73,12 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > THP_FAULT_ALLOC, > THP_FAULT_FALLBACK, > + THP_FAULT_FALLBACK_CHARGE, > THP_COLLAPSE_ALLOC, > THP_COLLAPSE_ALLOC_FAILED, > THP_FILE_ALLOC, > THP_FILE_FALLBACK, > + THP_FILE_FALLBACK_CHARGE, > THP_FILE_MAPPED, > THP_SPLIT_PAGE, > THP_SPLIT_PAGE_FAILED, > @@ -117,6 +119,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, > #ifndef CONFIG_TRANSPARENT_HUGEPAGE > #define THP_FILE_ALLOC ({ BUILD_BUG(); 0; }) > #define THP_FILE_FALLBACK ({ BUILD_BUG(); 0; }) > +#define THP_FILE_FALLBACK_CHARGE ({ BUILD_BUG(); 0; }) > #define THP_FILE_MAPPED ({ BUILD_BUG(); 0; }) > #endif > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -597,6 +597,7 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf, > if (mem_cgroup_try_charge_delay(page, vma->vm_mm, gfp, &memcg, true)) { > put_page(page); > count_vm_event(THP_FAULT_FALLBACK); > + count_vm_event(THP_FAULT_FALLBACK_CHARGE); > return VM_FAULT_FALLBACK; > } > > @@ -1406,6 +1407,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd) > put_page(page); > ret |= VM_FAULT_FALLBACK; > count_vm_event(THP_FAULT_FALLBACK); > + count_vm_event(THP_FAULT_FALLBACK_CHARGE); > goto out; > } > > diff --git a/mm/shmem.c b/mm/shmem.c > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1871,8 +1871,10 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, > error = mem_cgroup_try_charge_delay(page, charge_mm, gfp, &memcg, > PageTransHuge(page)); > if (error) { > - if (PageTransHuge(page)) > + if (PageTransHuge(page)) { > count_vm_event(THP_FILE_FALLBACK); > + count_vm_event(THP_FILE_FALLBACK_CHARGE); > + } > goto unacct; > } > error = shmem_add_to_page_cache(page, mapping, hindex, > diff --git a/mm/vmstat.c b/mm/vmstat.c > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -1254,10 +1254,12 @@ const char * const vmstat_text[] = { > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > "thp_fault_alloc", > "thp_fault_fallback", > + "thp_fault_fallback_charge", > "thp_collapse_alloc", > "thp_collapse_alloc_failed", > "thp_file_alloc", > "thp_file_fallback", > + "thp_file_fallback_charge", > "thp_file_mapped", > "thp_split_page", > "thp_split_page_failed",