On Tue, 27 Oct 2026 17:40:14 +0800
Xuewen Wang <[email protected]> wrote:
> index 7a0050a1686f..72b20d6b3caf 100644
> --- a/include/trace/events/shmem.h
> +++ b/include/trace/events/shmem.h
> @@ -80,6 +80,61 @@ TRACE_EVENT(shmem_swapin_folio,
> __entry->fallback_error, __entry->error)
> );
>
> +#define SHMEM_ALLOC_ALLOC 0
> +#define SHMEM_ALLOC_CHARGE 1
> +#define SHMEM_ALLOC_CACHE 2
> +#define SHMEM_ALLOC_ACCOUNT 3
> +#define SHMEM_ALLOC_DONE 4
> +#define SHMEM_ALLOC_FILTER 5
> +
> +TRACE_EVENT(shmem_alloc_folio_finish,
> +
> + TP_PROTO(struct inode *inode, pgoff_t index,
> + int requested_order, int suitable_order, int actual_order,
> + unsigned int stage, int error, int ret),
> +
> + TP_ARGS(inode, index, requested_order, suitable_order, actual_order,
> + stage, error, ret),
> +
> + TP_STRUCT__entry(
> + __field(dev_t, dev)
> + __field(unsigned long, ino)
> + __field(unsigned long, index)
Same here. Move dev to after index.
-- Steve
> + __field(int, requested_order)
> + __field(int, suitable_order)
> + __field(int, actual_order)
> + __field(unsigned int, stage)
> + __field(int, error)
> + __field(int, ret)
> + ),
> +
> + TP_fast_assign(
> + __entry->dev = inode->i_sb->s_dev;
> + __entry->ino = inode->i_ino;
> + __entry->index = index;
> + __entry->requested_order = requested_order;
> + __entry->suitable_order = suitable_order;
> + __entry->actual_order = actual_order;
> + __entry->stage = stage;
> + __entry->error = error;
> + __entry->ret = ret;
> + ),
> +
> + TP_printk("dev=%d:%d ino=%lu index=%lu requested_order=%d
> suitable_order=%d actual_order=%d stage=%s error=%d ret=%d",
> + MAJOR(__entry->dev), MINOR(__entry->dev),
> + __entry->ino, __entry->index,
> + __entry->requested_order, __entry->suitable_order,
> + __entry->actual_order,
> + __print_symbolic(__entry->stage,
> + { SHMEM_ALLOC_ALLOC, "alloc" },
> + { SHMEM_ALLOC_CHARGE, "charge" },
> + { SHMEM_ALLOC_CACHE, "cache" },
> + { SHMEM_ALLOC_ACCOUNT, "account" },
> + { SHMEM_ALLOC_DONE, "done" },
> + { SHMEM_ALLOC_FILTER, "filter" }),
> + __entry->error, __entry->ret)
> +);
> +
> #endif /* _TRACE_SHMEM_H */
>
> /* This part must be outside protection */
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 3b910aec5bcf..68321d61dfdb 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2155,17 +2155,23 @@ static struct folio *shmem_alloc_and_add_folio(struct
> vm_fault *vmf,
> unsigned long suitable_orders = 0;
> struct folio *folio = NULL;
> pgoff_t aligned_index;
> + pgoff_t orig_index = index;
> long pages;
> int error, order;
> + int requested_order, suitable_order;
> + int charge_error = 0;
> + unsigned int stage;
>
> if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
> orders = 0;
>
> + requested_order = orders ? highest_order(orders) : 0;
> if (orders > 0) {
> suitable_orders = shmem_suitable_orders(inode, vmf,
> mapping, index, orders);
>
> order = highest_order(suitable_orders);
> + suitable_order = order;
> while (suitable_orders) {
> pages = 1UL << order;
> aligned_index = round_down(index, pages);
> @@ -2181,19 +2187,35 @@ static struct folio *shmem_alloc_and_add_folio(struct
> vm_fault *vmf,
> order = next_order(&suitable_orders, order);
> }
> } else {
> + suitable_order = 0;
> pages = 1;
> folio = shmem_alloc_folio(gfp, 0, info, index);
> }
> - if (!folio)
> + if (!folio) {
> + if (suitable_order < 0)
> + trace_shmem_alloc_folio_finish(inode, orig_index,
> + requested_order,
> + suitable_order, -1,
> + SHMEM_ALLOC_FILTER, 0,
> + -ENOMEM);
> + else
> + trace_shmem_alloc_folio_finish(inode, orig_index,
> + requested_order,
> + suitable_order, -1,
> + SHMEM_ALLOC_ALLOC,
> -ENOMEM,
> + -ENOMEM);
> return ERR_PTR(-ENOMEM);
> + }
>
> allocated:
> __folio_set_locked(folio);
> __folio_set_swapbacked(folio);
>
> gfp &= GFP_RECLAIM_MASK;
> + stage = SHMEM_ALLOC_CHARGE;
> error = mem_cgroup_charge(folio, fault_mm, gfp);
> if (error) {
> + charge_error = error;
> if (xa_find(&mapping->i_pages, &index,
> index + pages - 1, XA_PRESENT)) {
> error = -EEXIST;
> @@ -2208,10 +2230,12 @@ static struct folio *shmem_alloc_and_add_folio(struct
> vm_fault *vmf,
> goto unlock;
> }
>
> + stage = SHMEM_ALLOC_CACHE;
> error = shmem_add_to_page_cache(folio, mapping, index, NULL, gfp);
> if (error)
> goto unlock;
>
> + stage = SHMEM_ALLOC_ACCOUNT;
> error = shmem_inode_acct_blocks(inode, pages);
> if (error) {
> struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
> @@ -2242,9 +2266,17 @@ static struct folio *shmem_alloc_and_add_folio(struct
> vm_fault *vmf,
>
> shmem_recalc_inode(inode, pages, 0);
> folio_add_lru(folio);
> + if (folio_order(folio) < requested_order)
> + trace_shmem_alloc_folio_finish(inode, orig_index,
> + requested_order, suitable_order,
> + folio_order(folio),
> + SHMEM_ALLOC_DONE, 0, 0);
> return folio;
>
> unlock:
> + trace_shmem_alloc_folio_finish(inode, orig_index, requested_order,
> + suitable_order, folio_order(folio),
> stage,
> + charge_error ?: error, error);
> folio_unlock(folio);
> folio_put(folio);
> return ERR_PTR(error);
