Re: [f2fs-dev] [PATCH v1] f2fs: Improve large section GC by locating valid block segments

From: yohan.joung
Date: Wed Apr 09 2025 - 20:18:20 EST

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hi jeageuk, chao
How about changing the large section gc in this direction?
Thanks

> Change the large section GC to locate valid block segments instead of
> performing a sequential search. This modification enhances performance
> by reducing unnecessary block scanning in large storage sections.
>
> example :
> [invalid seg 0] [invalid seg 1] [invalid seg 2]
> [ valid seg 3] [ valid seg 4] [ valid seg 5]
>
> Current: In the first GC, nothing is moved,
> but in the second GC, segments 3, 4, and 5 are moved.
> Change: In the first GC, segments 3, 4, and 5 are moved.
>
> Signed-off-by: yohan.joung <yohan.joung@xxxxxx>
> ---
> fs/f2fs/f2fs.h | 2 ++
> fs/f2fs/gc.c | 92 +++++++++++++++++++++++++++++++++++--------------
> fs/f2fs/gc.h | 6 ++++
> fs/f2fs/super.c | 8 ++++-
> 4 files changed, 82 insertions(+), 26 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index f1576dc6ec67..348417edac25 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -4008,6 +4008,8 @@ int f2fs_gc_range(struct f2fs_sb_info *sbi,
> int f2fs_resize_fs(struct file *filp, __u64 block_count);
> int __init f2fs_create_garbage_collection_cache(void);
> void f2fs_destroy_garbage_collection_cache(void);
> +int __init f2fs_init_garbage_collection_summary_cache(void);
> +void f2fs_destroy_garbage_collection_summary_cache(void);
> /* victim selection function for cleaning and SSR */
> int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,
> int gc_type, int type, char alloc_mode,
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 2b8f9239bede..3b63e85fa038 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -24,6 +24,7 @@
> #include <trace/events/f2fs.h>
>
> static struct kmem_cache *victim_entry_slab;
> +static struct kmem_cache *gc_page_entry_slab;
>
> static unsigned int count_bits(const unsigned long *addr,
> unsigned int offset, unsigned int len);
> @@ -711,6 +712,30 @@ static void release_victim_entry(struct f2fs_sb_info *sbi)
> f2fs_bug_on(sbi, !list_empty(&am->victim_list));
> }
>
> +static struct gc_page_entry *add_gc_page_entry(struct list_head *gc_page_list,
> + struct page *sum_page, unsigned int segno)
> +{
> + struct gc_page_entry *gpe;
> +
> + gpe = f2fs_kmem_cache_alloc(gc_page_entry_slab, GFP_NOFS, true, NULL);
> + gpe->segno = segno;
> + gpe->sum_page = sum_page;
> + list_add_tail(&gpe->list, gc_page_list);
> + return gpe;
> +}
> +
> +static void release_gc_page_entry(struct list_head *gc_page_list, bool putpage)
> +{
> + struct gc_page_entry *gpe, *tmp;
> +
> + list_for_each_entry_safe(gpe, tmp, gc_page_list, list) {
> + if (putpage)
> + f2fs_put_page(gpe->sum_page, 0);
> + list_del(&gpe->list);
> + kmem_cache_free(gc_page_entry_slab, gpe);
> + }
> +}
> +
> static bool f2fs_pin_section(struct f2fs_sb_info *sbi, unsigned int segno)
> {
> struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
> @@ -1721,14 +1746,18 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
> struct page *sum_page;
> struct f2fs_summary_block *sum;
> struct blk_plug plug;
> + struct gc_page_entry *gpe;
> unsigned int segno = start_segno;
> unsigned int end_segno = start_segno + SEGS_PER_SEC(sbi);
> unsigned int sec_end_segno;
> + unsigned int window_granularity = 1;
> int seg_freed = 0, migrated = 0;
> unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
> SUM_TYPE_DATA : SUM_TYPE_NODE;
> unsigned char data_type = (type == SUM_TYPE_DATA) ? DATA : NODE;
> int submitted = 0;
> + int gc_list_count = 0;
> + LIST_HEAD(gc_page_list);
>
> if (__is_large_section(sbi)) {
> sec_end_segno = rounddown(end_segno, SEGS_PER_SEC(sbi));
> @@ -1744,7 +1773,7 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
> f2fs_usable_segs_in_sec(sbi);
>
> if (gc_type == BG_GC || one_time) {
> - unsigned int window_granularity =
> + window_granularity =
> sbi->migration_window_granularity;
>
> if (f2fs_sb_has_blkzoned(sbi) &&
> @@ -1752,8 +1781,6 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
> sbi->gc_thread->boost_zoned_gc_percent))
> window_granularity *=
> BOOST_GC_MULTIPLE;
> -
> - end_segno = start_segno + window_granularity;
> }
>
> if (end_segno > sec_end_segno)
> @@ -1762,37 +1789,38 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
>
> sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
>
> - /* readahead multi ssa blocks those have contiguous address */
> - if (__is_large_section(sbi))
> + for (segno = start_segno; segno < end_segno; segno++) {
> + if (!get_valid_blocks(sbi, segno, false))
> + continue;
> +
> + /* readahead multi ssa blocks those have contiguous address */
> f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
> - end_segno - segno, META_SSA, true);
> + window_granularity, META_SSA, true);
>
> - /* reference all summary page */
> - while (segno < end_segno) {
> - sum_page = f2fs_get_sum_page(sbi, segno++);
> + /* reference all summary page */
> + sum_page = f2fs_get_sum_page(sbi, segno);
> if (IS_ERR(sum_page)) {
> int err = PTR_ERR(sum_page);
> -
> - end_segno = segno - 1;
> - for (segno = start_segno; segno < end_segno; segno++) {
> - sum_page = find_get_page(META_MAPPING(sbi),
> - GET_SUM_BLOCK(sbi, segno));
> - f2fs_put_page(sum_page, 0);
> - f2fs_put_page(sum_page, 0);
> - }
> + release_gc_page_entry(&gc_page_list, true);
> return err;
> }
> + add_gc_page_entry(&gc_page_list, sum_page, segno);
> unlock_page(sum_page);
> + if (++gc_list_count >= window_granularity)
> + break;
> }
>
> blk_start_plug(&plug);
>
> - for (segno = start_segno; segno < end_segno; segno++) {
> + list_for_each_entry(gpe, &gc_page_list, list) {
>
> /* find segment summary of victim */
> - sum_page = find_get_page(META_MAPPING(sbi),
> - GET_SUM_BLOCK(sbi, segno));
> - f2fs_put_page(sum_page, 0);
> + sum_page = gpe->sum_page;
> + segno = gpe->segno;
> + if (!sum_page) {
> + f2fs_err(sbi, "Failed to get summary page for segment %u", segno);
> + goto skip;
> + }
>
> if (get_valid_blocks(sbi, segno, false) == 0)
> goto freed;
> @@ -1835,18 +1863,20 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
> get_valid_blocks(sbi, segno, false) == 0)
> seg_freed++;
>
> - if (__is_large_section(sbi))
> - sbi->next_victim_seg[gc_type] =
> - (segno + 1 < sec_end_segno) ?
> - segno + 1 : NULL_SEGNO;
> skip:
> f2fs_put_page(sum_page, 0);
> }
>
> + if (__is_large_section(sbi) && !list_empty(&gc_page_list))
> + sbi->next_victim_seg[gc_type] =
> + (segno + 1 < sec_end_segno) ?
> + segno + 1 : NULL_SEGNO;
> +
> if (submitted)
> f2fs_submit_merged_write(sbi, data_type);
>
> blk_finish_plug(&plug);
> + release_gc_page_entry(&gc_page_list, false);
>
> if (migrated)
> stat_inc_gc_sec_count(sbi, data_type, gc_type);
> @@ -2008,6 +2038,18 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
> return ret;
> }
>
> +int __init f2fs_init_garbage_collection_summary_cache(void)
> +{
> + gc_page_entry_slab = f2fs_kmem_cache_create("f2fs_gc_page_entry",
> + sizeof(struct gc_page_entry));
> + return gc_page_entry_slab ? 0 : -ENOMEM;
> +}
> +
> +void f2fs_destroy_garbage_collection_summary_cache(void)
> +{
> + kmem_cache_destroy(gc_page_entry_slab);
> +}
> +
> int __init f2fs_create_garbage_collection_cache(void)
> {
> victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
> diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
> index 5c1eaf55e127..9c8695efe394 100644
> --- a/fs/f2fs/gc.h
> +++ b/fs/f2fs/gc.h
> @@ -82,6 +82,12 @@ struct victim_entry {
> struct list_head list;
> };
>
> +struct gc_page_entry {
> + unsigned int segno;
> + struct page *sum_page;
> + struct list_head list;
> +};
> +
> /*
> * inline functions
> */
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index f087b2b71c89..a3241730fe4f 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -5090,9 +5090,12 @@ static int __init init_f2fs_fs(void)
> err = f2fs_create_garbage_collection_cache();
> if (err)
> goto free_extent_cache;
> - err = f2fs_init_sysfs();
> + err = f2fs_init_garbage_collection_summary_cache();
> if (err)
> goto free_garbage_collection_cache;
> + err = f2fs_init_sysfs();
> + if (err)
> + goto free_garbage_collection_summary_cache;
> err = f2fs_init_shrinker();
> if (err)
> goto free_sysfs;
> @@ -5141,6 +5144,8 @@ static int __init init_f2fs_fs(void)
> f2fs_exit_shrinker();
> free_sysfs:
> f2fs_exit_sysfs();
> +free_garbage_collection_summary_cache:
> + f2fs_destroy_garbage_collection_summary_cache();
> free_garbage_collection_cache:
> f2fs_destroy_garbage_collection_cache();
> free_extent_cache:
> @@ -5172,6 +5177,7 @@ static void __exit exit_f2fs_fs(void)
> f2fs_destroy_root_stats();
> f2fs_exit_shrinker();
> f2fs_exit_sysfs();
> + f2fs_destroy_garbage_collection_summary_cache();
> f2fs_destroy_garbage_collection_cache();
> f2fs_destroy_extent_cache();
> f2fs_destroy_recovery_cache();
> --
> 2.33.0
>
>
>
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx

Next message: Andy Yan: "Re:[PATCH] media: verisilicono: Enable NV15 support for Rockchip VDPU981"
Previous message: Jakub Kicinski: "Re: [PATCH v2 00/14] Add Microchip ZL3073x support (part 1)"
Next in thread: Chao Yu: "Re: [f2fs-dev] [PATCH v1] f2fs: Improve large section GC by locating valid block segments"
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