Re: [PATCH 1/4] mm: rearrange node_stat_item to put memcg stats at start

[Chris Li <chrisl@kernel.org>]

On Mon, Apr 22, 2024 at 10:19 PM Shakeel Butt <shakeel.butt@linux.dev> wrote:
>
> At the moment the memcg stats are sized based on the size of enum
> node_stat_item but not all fields in node_stat_item corresponds to memcg
> stats. So, rearrage the contents of node_stat_item such that all the
> memcg specific stats are at the top and then the later patches will make
> sure that the memcg code will not waste space for non-memcg stats.

Is this patch meant to have no functional change other than the output order?
It would be better to clarify it in the commit message if that is the case.

Chris

>
> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
> ---
>  include/linux/mmzone.h | 25 +++++++++++++------------
>  mm/vmstat.c            | 24 ++++++++++++------------
>  2 files changed, 25 insertions(+), 24 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 8f9c9590a42c..989ca97402c6 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -166,9 +166,6 @@ enum node_stat_item {
>         NR_UNEVICTABLE,         /*  "     "     "   "       "         */
>         NR_SLAB_RECLAIMABLE_B,
>         NR_SLAB_UNRECLAIMABLE_B,
> -       NR_ISOLATED_ANON,       /* Temporary isolated pages from anon lru */
> -       NR_ISOLATED_FILE,       /* Temporary isolated pages from file lru */
> -       WORKINGSET_NODES,
>         WORKINGSET_REFAULT_BASE,
>         WORKINGSET_REFAULT_ANON = WORKINGSET_REFAULT_BASE,
>         WORKINGSET_REFAULT_FILE,
> @@ -179,39 +176,43 @@ enum node_stat_item {
>         WORKINGSET_RESTORE_ANON = WORKINGSET_RESTORE_BASE,
>         WORKINGSET_RESTORE_FILE,
>         WORKINGSET_NODERECLAIM,
> +       NR_PAGETABLE,           /* used for pagetables */
> +       NR_SECONDARY_PAGETABLE, /* secondary pagetables, KVM & IOMMU */
> +       NR_KERNEL_STACK_KB,     /* measured in KiB */
>         NR_ANON_MAPPED, /* Mapped anonymous pages */
>         NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
>                            only modified from process context */
>         NR_FILE_PAGES,
> +#ifdef CONFIG_SWAP
> +       NR_SWAPCACHE,
> +#endif
>         NR_FILE_DIRTY,
>         NR_WRITEBACK,
> -       NR_WRITEBACK_TEMP,      /* Writeback using temporary buffers */
>         NR_SHMEM,               /* shmem pages (included tmpfs/GEM pages) */
>         NR_SHMEM_THPS,
> -       NR_SHMEM_PMDMAPPED,
>         NR_FILE_THPS,
> -       NR_FILE_PMDMAPPED,
>         NR_ANON_THPS,
> +       /* No memcg stats for the following fields. */
> +       NR_SHMEM_PMDMAPPED,
> +       NR_FILE_PMDMAPPED,
> +       NR_WRITEBACK_TEMP,      /* Writeback using temporary buffers */
>         NR_VMSCAN_WRITE,
>         NR_VMSCAN_IMMEDIATE,    /* Prioritise for reclaim when writeback ends */
> +       NR_ISOLATED_ANON,       /* Temporary isolated pages from anon lru */
> +       NR_ISOLATED_FILE,       /* Temporary isolated pages from file lru */
> +       WORKINGSET_NODES,
>         NR_DIRTIED,             /* page dirtyings since bootup */
>         NR_WRITTEN,             /* page writings since bootup */
>         NR_THROTTLED_WRITTEN,   /* NR_WRITTEN while reclaim throttled */
>         NR_KERNEL_MISC_RECLAIMABLE,     /* reclaimable non-slab kernel pages */
>         NR_FOLL_PIN_ACQUIRED,   /* via: pin_user_page(), gup flag: FOLL_PIN */
>         NR_FOLL_PIN_RELEASED,   /* pages returned via unpin_user_page() */
> -       NR_KERNEL_STACK_KB,     /* measured in KiB */
>  #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
>         NR_KERNEL_SCS_KB,       /* measured in KiB */
>  #endif
> -       NR_PAGETABLE,           /* used for pagetables */
> -       NR_SECONDARY_PAGETABLE, /* secondary pagetables, KVM & IOMMU */
>  #ifdef CONFIG_IOMMU_SUPPORT
>         NR_IOMMU_PAGES,         /* # of pages allocated by IOMMU */
>  #endif
> -#ifdef CONFIG_SWAP
> -       NR_SWAPCACHE,
> -#endif
>  #ifdef CONFIG_NUMA_BALANCING
>         PGPROMOTE_SUCCESS,      /* promote successfully */
>         PGPROMOTE_CANDIDATE,    /* candidate pages to promote */
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 8507c497218b..4eac2f6322a3 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1206,9 +1206,6 @@ const char * const vmstat_text[] = {
>         "nr_unevictable",
>         "nr_slab_reclaimable",
>         "nr_slab_unreclaimable",
> -       "nr_isolated_anon",
> -       "nr_isolated_file",
> -       "workingset_nodes",
>         "workingset_refault_anon",
>         "workingset_refault_file",
>         "workingset_activate_anon",
> @@ -1216,38 +1213,41 @@ const char * const vmstat_text[] = {
>         "workingset_restore_anon",
>         "workingset_restore_file",
>         "workingset_nodereclaim",
> +       "nr_page_table_pages",
> +       "nr_sec_page_table_pages",
> +       "nr_kernel_stack",
>         "nr_anon_pages",
>         "nr_mapped",
>         "nr_file_pages",
> +#ifdef CONFIG_SWAP
> +       "nr_swapcached",
> +#endif
>         "nr_dirty",
>         "nr_writeback",
> -       "nr_writeback_temp",
>         "nr_shmem",
>         "nr_shmem_hugepages",
> -       "nr_shmem_pmdmapped",
>         "nr_file_hugepages",
> -       "nr_file_pmdmapped",
>         "nr_anon_transparent_hugepages",
> +       "nr_shmem_pmdmapped",
> +       "nr_file_pmdmapped",
> +       "nr_writeback_temp",
>         "nr_vmscan_write",
>         "nr_vmscan_immediate_reclaim",
> +       "nr_isolated_anon",
> +       "nr_isolated_file",
> +       "workingset_nodes",
>         "nr_dirtied",
>         "nr_written",
>         "nr_throttled_written",
>         "nr_kernel_misc_reclaimable",
>         "nr_foll_pin_acquired",
>         "nr_foll_pin_released",
> -       "nr_kernel_stack",
>  #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
>         "nr_shadow_call_stack",
>  #endif
> -       "nr_page_table_pages",
> -       "nr_sec_page_table_pages",
>  #ifdef CONFIG_IOMMU_SUPPORT
>         "nr_iommu_pages",
>  #endif
> -#ifdef CONFIG_SWAP
> -       "nr_swapcached",
> -#endif
>  #ifdef CONFIG_NUMA_BALANCING
>         "pgpromote_success",
>         "pgpromote_candidate",
> --
> 2.43.0
>
>