Re: [PATCH v3] mm/alloc_tag: replace fixed-size early PFN array with dynamic linked list

[Suren Baghdasaryan]

On Wed, Apr 29, 2026 at 12:04 AM Hao Ge <hao.ge@xxxxxxxxx> wrote:
>
> Hi Suren
>
>
> On 2026/4/29 13:47, Suren Baghdasaryan wrote:
> > On Mon, Apr 27, 2026 at 8:01 PM Hao Ge <hao.ge@xxxxxxxxx> wrote:
> >> Hi Suren
> >>
> >>
> >> Thanks a lot for your review and suggestions.
> >>
> >>
> >> On 2026/4/28 00:02, Suren Baghdasaryan wrote:
> >>> On Thu, Apr 23, 2026 at 1:39 AM Hao Ge <hao.ge@xxxxxxxxx> wrote:
> >>>> Pages allocated before page_ext is available have their codetag left
> >>>> uninitialized. Track these early PFNs and clear their codetag in
> >>>> clear_early_alloc_pfn_tag_refs() to avoid "alloc_tag was not set"
> >>>> warnings when they are freed later.
> >>>>
> >>>> Currently a fixed-size array of 8192 entries is used, with a warning if
> >>>> the limit is exceeded. However, the number of early allocations depends
> >>>> on the number of CPUs and can be larger than 8192.
> >>>>
> >>>> Replace the fixed-size array with a dynamically allocated linked list
> >>>> of pages. Each page stores PFNs in its page body and uses page->lru
> >>>> to link to the next page, with page->private tracking the number of
> >>>> used slots.
> >>>>
> >>>> The list pages themselves are allocated via alloc_page(), which would
> >>>> trigger __pgalloc_tag_add() -> alloc_tag_add_early_pfn() and recurse
> >>>> indefinitely. Introduce __GFP_NO_CODETAG (reuses the %__GFP_NO_OBJ_EXT
> >>>> bit) and pass gfp_flags through pgalloc_tag_add() so that the early path
> >>>> can skip recording allocations that carry this flag.
> >>>>
> >>>> Signed-off-by: Hao Ge <hao.ge@xxxxxxxxx>
> >>>> ---
> >>>> v3:
> >>>> - Simplify linked list: use page->lru for chaining and page->private as
> >>>>     slot counter, removing the early_pfn_node struct and freelist (suggested
> >>>>     by Suren Baghdasaryan)
> >>>> - Pass gfp_flags through alloc_tag_add_early_pfn() but strip
> >>>>     __GFP_DIRECT_RECLAIM instead of selecting GFP_KERNEL/GFP_ATOMIC,
> >>>>     because __alloc_tag_add_early_pfn() is invoked under rcu_read_lock().
> >>>>
> >>>> v2:
> >>>> - Use cmpxchg to atomically update early_pfn_pages, preventing page leak under concurrent allocation
> >>>> - Pass gfp_flags through the full call chain and use gfpflags_allow_blocking()
> >>>>     to select GFP_KERNEL vs GFP_ATOMIC, avoiding unnecessary GFP_ATOMIC in process context
> >>>> ---
> >>>>    include/linux/alloc_tag.h |  22 ++++++-
> >>>>    lib/alloc_tag.c           | 118 +++++++++++++++++++++-----------------
> >>>>    mm/page_alloc.c           |  23 ++++----
> >>>>    3 files changed, 97 insertions(+), 66 deletions(-)
> >>>>
> >>>> diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h
> >>>> index 02de2ede560f..ce9b478033bf 100644
> >>>> --- a/include/linux/alloc_tag.h
> >>>> +++ b/include/linux/alloc_tag.h
> >>>> @@ -150,6 +150,23 @@ static inline struct alloc_tag_counters alloc_tag_read(struct alloc_tag *tag)
> >>>>    }
> >>>>
> >>>>    #ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG
> >>>> +/*
> >>>> + * Skip early PFN recording for a page allocation.  Reuses the
> >>>> + * %__GFP_NO_OBJ_EXT bit.  Used by __alloc_tag_add_early_pfn() to avoid
> >>>> + * recursion when allocating pages for the early PFN tracking list
> >>>> + * itself.
> >>>> + *
> >>>> + * Callers must set the codetag to CODETAG_EMPTY (via
> >>>> + * clear_page_tag_ref()) before freeing pages allocated with this
> >>>> + * flag once page_ext becomes available, otherwise
> >>>> + * alloc_tag_sub_check() will trigger a warning.
> >>> nit: Callers must... sounds like someone who uses
> >>> __alloc_tag_add_early_pfn() has to do something extra, however
> >>> clear_page_tag_ref() is done by clear_early_alloc_pfn_tag_refs(), so
> >>> callers don't really need to do this. I suggest rephrasing as:
> >>>
> >>> Codetags of the pages allocated with __GFP_NO_CODETAG should be
> >>> cleared (via clear_page_tag_ref()) before freeing the pages to prevent
> >>> alloc_tag_sub_check() from triggering a warning.
> >> That's reasonable.
> >>
> >> I will adjust the wording in v2.
> >>>> + */
> >>>> +#define __GFP_NO_CODETAG       __GFP_NO_OBJ_EXT
> >>>> +
> >>>> +static inline bool should_record_early_pfn(gfp_t gfp_flags)
> >>>> +{
> >>>> +       return !(gfp_flags & __GFP_NO_CODETAG);
> >>>> +}
> >>>>    static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag)
> >>>>    {
> >>>>           WARN_ONCE(ref && ref->ct && !is_codetag_empty(ref),
> >>>> @@ -163,11 +180,12 @@ static inline void alloc_tag_sub_check(union codetag_ref *ref)
> >>>>    {
> >>>>           WARN_ONCE(ref && !ref->ct, "alloc_tag was not set\n");
> >>>>    }
> >>>> -void alloc_tag_add_early_pfn(unsigned long pfn);
> >>>> +void alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags);
> >>>>    #else
> >>>>    static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag) {}
> >>>>    static inline void alloc_tag_sub_check(union codetag_ref *ref) {}
> >>>> -static inline void alloc_tag_add_early_pfn(unsigned long pfn) {}
> >>>> +static inline void alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags) {}
> >>>> +static inline bool should_record_early_pfn(gfp_t gfp_flags) { return false; }
> >>>>    #endif
> >>>>
> >>>>    /* Caller should verify both ref and tag to be valid */
> >>>> diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
> >>>> index ed1bdcf1f8ab..a00dc5a867e4 100644
> >>>> --- a/lib/alloc_tag.c
> >>>> +++ b/lib/alloc_tag.c
> >>>> @@ -766,45 +766,49 @@ static __init bool need_page_alloc_tagging(void)
> >>>>     * Some pages are allocated before page_ext becomes available, leaving
> >>>>     * their codetag uninitialized. Track these early PFNs so we can clear
> >>>>     * their codetag refs later to avoid warnings when they are freed.
> >>>> - *
> >>>> - * Early allocations include:
> >>>> - *   - Base allocations independent of CPU count
> >>>> - *   - Per-CPU allocations (e.g., CPU hotplug callbacks during smp_init,
> >>>> - *     such as trace ring buffers, scheduler per-cpu data)
> >>>> - *
> >>>> - * For simplicity, we fix the size to 8192.
> >>>> - * If insufficient, a warning will be triggered to alert the user.
> >>>> - *
> >>>> - * TODO: Replace fixed-size array with dynamic allocation using
> >>>> - * a GFP flag similar to ___GFP_NO_OBJ_EXT to avoid recursion.
> >>>>     */
> >>>> -#define EARLY_ALLOC_PFN_MAX            8192
> >>>> +#define EARLY_PFNS_PER_PAGE            (PAGE_SIZE / sizeof(unsigned long))
> >>>>
> >>>> -static unsigned long early_pfns[EARLY_ALLOC_PFN_MAX] __initdata;
> >>>> -static atomic_t early_pfn_count __initdata = ATOMIC_INIT(0);
> >>>> +static struct page *early_pfn_current __initdata;
> >>> So, instead of using early_pfn_current as the head page and then
> >>> page->lru.next directly, I would suggest having "struct llist_head
> >>> early_pfn_head;" as the list head and either using page->pcp_llist to
> >>> link the pages or even better, adding a "struct llist_node llist;"
> >>> into the union containing "struct list_head lru;". Note that
> >>> llist_add() uses try_cmpxchg(), so the link addition is atomic.
> >> Adding a struct llist_node into the page union only for the
> >> CONFIG_MEM_ALLOC_PROFILING_DEBUG feature,
> >>
> >> which may not be quite appropriate from a design perspective.
> >>
> >>> And you should probably use folios rather than pages to follow the new trends.
> >>>
> >>>> -static void __init __alloc_tag_add_early_pfn(unsigned long pfn)
> >>>> +static void __init __alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags)
> >>>>    {
> >>>> -       int old_idx, new_idx;
> >>>> +       struct page *page;
> >>>> +       unsigned long idx;
> >>>>
> >>>>           do {
> >>>> -               old_idx = atomic_read(&early_pfn_count);
> >>>> -               if (old_idx >= EARLY_ALLOC_PFN_MAX) {
> >>>> -                       pr_warn_once("Early page allocations before page_ext init exceeded EARLY_ALLOC_PFN_MAX (%d)\n",
> >>>> -                                     EARLY_ALLOC_PFN_MAX);
> >>>> -                       return;
> >>>> +               page = READ_ONCE(early_pfn_current);
> >>>> +               if (!page || READ_ONCE(page->private) >= EARLY_PFNS_PER_PAGE) {
> >>>> +                       gfp_t gfp = gfp_flags & ~__GFP_DIRECT_RECLAIM;
> >>>> +                       struct page *new = alloc_page(gfp | __GFP_NO_CODETAG);
> >>>> +
> >>>> +                       if (!new) {
> >>>> +                               pr_warn_once("early PFN tracking page allocation failed\n");
> >>>> +                               return;
> >>>> +                       }
> >>>> +                       new->lru.next = (struct list_head *)page;
> >>>> +                       if (cmpxchg(&early_pfn_current, page, new) != page) {
> >>>> +                               __free_page(new);
> >>>> +                               continue;
> >>>> +                       }
> >>
> >> I also considered using llist_head initially.  like this
> >>
> >> static LLIST_HEAD(early_pfn_pages);
> >>
> >> static void __init __alloc_tag_add_early_pfn(unsigned long pfn, gfp_t
> >> gfp_flags)
> >> {
> >>           struct page *page;
> >>           unsigned long idx;
> >>
> >>           do {
> >>                   page = llist_first(&early_pfn_pages);
> >>                   if (!page || READ_ONCE(page->private) >=
> >> EARLY_PFNS_PER_PAGE) {
> >>                           gfp_t gfp = gfp_flags & ~__GFP_DIRECT_RECLAIM;
> >>                           struct page *new = alloc_page(gfp |
> >> __GFP_NO_CODETAG);
> >>
> >>                           if (!new) {
> >>                                   pr_warn_once("early PFN tracking page
> >> allocation failed\n");
> >>                                   return;
> >>                           }
> >>                           new->private = 0;
> >>                           llist_add(&new->pcp_llist, &early_pfn_pages);
> >>                           page = new;
> >>                   }
> >>                   idx = READ_ONCE(page->private);
> >>                   if (idx >= EARLY_PFNS_PER_PAGE)
> >>                           continue;
> >>                   if (cmpxchg(&page->private, idx, idx + 1) == idx)
> >>                           break;
> >>           } while (1);
> >>
> >>           ((unsigned long *)page_address(page))[idx] = pfn;
> >> }
> >>
> >>
> >> The problem is that llist_add() retries internally until it succeeds.
> >>
> >> When multiple CPUs concurrently see that the head page is NULL or full ,
> >>
> >> they each allocate a new tracking page and all insertions succeed:
> >>
> >> CPU0: head page A is full or NULL, allocates B, llist_add(B) → head=B→A
> >>
> >> CPU1: head page A is full or NULL, allocates C, llist_add(C) → head=C→B→A
> >>
> >> CPU0: claims slot 0 in B
> >>
> >> CPU1: claims slot 0 in C
> >>
> >> Now the head is C. Once C fills up, a new page D is allocated and
> >> becomes the new head. But B still has ~511 unused slots and will never
> >>
> >> be the head again — we only ever look at llist_first(). Those slots are
> >> permanently wasted.
> >>
> >> That's why I used struct page *early_pfn_current with direct cmpxchg —
> >> the loser frees its page and retries, avoiding the waste.
> >>
> >> That said, I may be missing something. Is there a way to use llist that
> >> avoids this? I'd appreciate your thoughts.
> > No, I think you are right, that retry logic in llist_add() does not
> > work for our case. I think the code you have works, but the way it
> > uses page attributes is kinda hacky and confusing. If we have to open
> > code the linked list handling then maybe just do this:
> >
> > struct pfn_arr_hdr {
> >      struct pfn_arr *next;
> >      atomic_t count;
> > };
> >
> > #define PFN_ARR_SIZE ((PAGE_SIZE - sizeof(struct pfn_arr_hdr)) /
> > sizeof(unsigned long))
> >
> > struct pfn_arr {
> >      struct pfn_arr_hdr hdr;
> >      unsigned long pfns[PFN_ARR_SIZE];
> > };
> >
> > So, instead of allocating pages, you use kmalloc() to allocate struct
> > pfn_arr and fill pfn_arr.pfns until it's full using pfn_arr.hdr.count
> > to track the array size. When current pfn_arr is full, you allocate a
> > new pfn_arr and link them via pfn_arr.hdr.next atomically, the way you
> > are doing with pages. That seems cleaner to me. WDYT?
>
> Actually, using kmalloc() would not be safe either, as page allocations
> can occur before kmalloc() becomes available.

I see.

>
> For example:
>
> memblock_free_all()       ← buddy allocator ready
>
> mem_init()
>
>      preallocate_vmalloc_pages()
>
>          p4d_alloc() / pud_alloc()
>
>              alloc_pages() -> triggers alloc_tag_add_early_pfn()
>
> kmem_cache_init() -> kmalloc becomes available
>
> Using alloc_page() is the safest choice — the very fact that we reach
> alloc_tag_add_early_pfn() means a page allocation via the buddy
>
> allocator has already succeeded, so the buddy allocator is guaranteed to
> be ready.
>
> How about keeping alloc_page() but mapping the page body to a proper struct?
>
> struct pfn_pool {
>
>      struct pfn_pool *next;
>
>      atomic_t count;
>
>      unsigned long pfns[];
>
> };
>
> The first few bytes of the page hold metadata (next pointer and slot
> count), the remainder stores PFNs.
>
> WDYT?

Yeah, that sounds good to me.

>
> Thanks.
>
> Best regards.
>
> Hao
>
> >
> >>
> >>>> +                       page = new;
> >>>>                   }
> >>>> -               new_idx = old_idx + 1;
> >>>> -       } while (!atomic_try_cmpxchg(&early_pfn_count, &old_idx, new_idx));
> >>>> +               idx = READ_ONCE(page->private);
> >>>> +               if (idx >= EARLY_PFNS_PER_PAGE)
> >>>> +                       continue;
> >>>> +               if (cmpxchg(&page->private, idx, idx + 1) != idx)
> >>>> +                       continue;
> >>>> +               break;
> >>> nit: This would read more easily:
> >>>
> >>>                  if (cmpxchg(&page->private, idx, idx + 1) == idx)
> >>>                           break;
> >> will fix in the next version.
> >>>> +       } while (1);
> >>>>
> >>>> -       early_pfns[old_idx] = pfn;
> >>>> +       ((unsigned long *)page_address(page))[idx] = pfn;
> >>>>    }
> >>>>
> >>>> -typedef void alloc_tag_add_func(unsigned long pfn);
> >>>> +typedef void alloc_tag_add_func(unsigned long pfn, gfp_t gfp_flags);
> >>>>    static alloc_tag_add_func __rcu *alloc_tag_add_early_pfn_ptr __refdata =
> >>>>           RCU_INITIALIZER(__alloc_tag_add_early_pfn);
> >>>>
> >>>> -void alloc_tag_add_early_pfn(unsigned long pfn)
> >>>> +void alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags)
> >>>>    {
> >>>>           alloc_tag_add_func *alloc_tag_add;
> >>>>
> >>>> @@ -814,13 +818,14 @@ void alloc_tag_add_early_pfn(unsigned long pfn)
> >>>>           rcu_read_lock();
> >>>>           alloc_tag_add = rcu_dereference(alloc_tag_add_early_pfn_ptr);
> >>>>           if (alloc_tag_add)
> >>>> -               alloc_tag_add(pfn);
> >>>> +               alloc_tag_add(pfn, gfp_flags);
> >>>>           rcu_read_unlock();
> >>>>    }
> >>>>
> >>>>    static void __init clear_early_alloc_pfn_tag_refs(void)
> >>>>    {
> >>>> -       unsigned int i;
> >>>> +       struct page *page, *next;
> >>>> +       unsigned long i;
> >>>>
> >>>>           if (static_key_enabled(&mem_profiling_compressed))
> >>>>                   return;
> >>>> @@ -829,37 +834,42 @@ static void __init clear_early_alloc_pfn_tag_refs(void)
> >>>>           /* Make sure we are not racing with __alloc_tag_add_early_pfn() */
> >>>>           synchronize_rcu();
> >>>>
> >>>> -       for (i = 0; i < atomic_read(&early_pfn_count); i++) {
> >>>> -               unsigned long pfn = early_pfns[i];
> >>>> -
> >>>> -               if (pfn_valid(pfn)) {
> >>>> -                       struct page *page = pfn_to_page(pfn);
> >>>> -                       union pgtag_ref_handle handle;
> >>>> -                       union codetag_ref ref;
> >>>> -
> >>>> -                       if (get_page_tag_ref(page, &ref, &handle)) {
> >>>> -                               /*
> >>>> -                                * An early-allocated page could be freed and reallocated
> >>>> -                                * after its page_ext is initialized but before we clear it.
> >>>> -                                * In that case, it already has a valid tag set.
> >>>> -                                * We should not overwrite that valid tag with CODETAG_EMPTY.
> >>>> -                                *
> >>>> -                                * Note: there is still a small race window between checking
> >>>> -                                * ref.ct and calling set_codetag_empty(). We accept this
> >>>> -                                * race as it's unlikely and the extra complexity of atomic
> >>>> -                                * cmpxchg is not worth it for this debug-only code path.
> >>>> -                                */
> >>>> -                               if (ref.ct) {
> >>>> +       for (page = early_pfn_current; page; page = next) {
> >>>> +               for (i = 0; i < page->private; i++) {
> >>>> +                       unsigned long pfn = ((unsigned long *)page_address(page))[i];
> >>> This page_address() can be done in the outer loop since the page does
> >>> not change inside the inner loop.
> >> will fix in the next version.
> >>>> +
> >>>> +                       if (pfn_valid(pfn)) {
> >>>> +                               union pgtag_ref_handle handle;
> >>>> +                               union codetag_ref ref;
> >>>> +
> >>>> +                               if (get_page_tag_ref(pfn_to_page(pfn), &ref, &handle)) {
> >>>> +                                       /*
> >>>> +                                        * An early-allocated page could be freed and reallocated
> >>>> +                                        * after its page_ext is initialized but before we clear it.
> >>>> +                                        * In that case, it already has a valid tag set.
> >>>> +                                        * We should not overwrite that valid tag
> >>>> +                                        * with CODETAG_EMPTY.
> >>>> +                                        *
> >>>> +                                        * Note: there is still a small race window between checking
> >>>> +                                        * ref.ct and calling set_codetag_empty(). We accept this
> >>>> +                                        * race as it's unlikely and the extra complexity of atomic
> >>>> +                                        * cmpxchg is not worth it for this debug-only code path.
> >>>> +                                        */
> >>>> +                                       if (ref.ct) {
> >>>> +                                               put_page_tag_ref(handle);
> >>>> +                                               continue;
> >>>> +                                       }
> >>>> +
> >>>> +                                       set_codetag_empty(&ref);
> >>>> +                                       update_page_tag_ref(handle, &ref);
> >>>>                                           put_page_tag_ref(handle);
> >>>> -                                       continue;
> >>>>                                   }
> >>>> -
> >>>> -                               set_codetag_empty(&ref);
> >>>> -                               update_page_tag_ref(handle, &ref);
> >>>> -                               put_page_tag_ref(handle);
> >>>>                           }
> >>>>                   }
> >>>>
> >>>> +               next = (struct page *)page->lru.next;
> >>>> +               clear_page_tag_ref(page);
> >>>> +               __free_page(page);
> >>>>           }
> >>>>    }
> >>>>    #else /* !CONFIG_MEM_ALLOC_PROFILING_DEBUG */
> >>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> >>>> index 04494bc2e46f..5b7b234967a5 100644
> >>>> --- a/mm/page_alloc.c
> >>>> +++ b/mm/page_alloc.c
> >>>> @@ -1284,7 +1284,7 @@ void __clear_page_tag_ref(struct page *page)
> >>>>    /* Should be called only if mem_alloc_profiling_enabled() */
> >>>>    static noinline
> >>>>    void __pgalloc_tag_add(struct page *page, struct task_struct *task,
> >>>> -                      unsigned int nr)
> >>>> +                      unsigned int nr, gfp_t gfp_flags)
> >>>>    {
> >>>>           union pgtag_ref_handle handle;
> >>>>           union codetag_ref ref;
> >>>> @@ -1294,21 +1294,24 @@ void __pgalloc_tag_add(struct page *page, struct task_struct *task,
> >>>>                   update_page_tag_ref(handle, &ref);
> >>>>                   put_page_tag_ref(handle);
> >>>>           } else {
> >>>> -               /*
> >>>> -                * page_ext is not available yet, record the pfn so we can
> >>>> -                * clear the tag ref later when page_ext is initialized.
> >>>> -                */
> >>>> -               alloc_tag_add_early_pfn(page_to_pfn(page));
> >>>> +
> >>>>                   if (task->alloc_tag)
> >>>>                           alloc_tag_set_inaccurate(task->alloc_tag);
> >>>> +
> >>>> +               /*
> >>>> +                * page_ext is not available yet, record the pfn so the
> >>>> +                * tag ref can be cleared later when page_ext is initialized.
> >>>> +                */
> >>>> +               if (should_record_early_pfn(gfp_flags))
> >>>> +                       alloc_tag_add_early_pfn(page_to_pfn(page), gfp_flags);
> >>> Any reason for changing the order of alloc_tag_add_early_pfn() and
> >>> alloc_tag_set_inaccurate()? I liked the previous version where we
> >>> explain why this is done at the very beginning of the block. You could
> >>> also call should_record_early_pfn() from inside
> >>> alloc_tag_add_early_pfn(), which would keep both
> >>> should_record_early_pfn() and __GFP_NO_CODETAG definitions local to
> >>> alloc_tag.c.
> >>>
> >> will fix in the next version.
> >>
> >> Thanks
> >>
> >> Best regards.
> >>
> >> Hao
> >>
> >>>>           }
> >>>>    }
> >>>>
> >>>>    static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,
> >>>> -                                  unsigned int nr)
> >>>> +                                  unsigned int nr, gfp_t gfp_flags)
> >>>>    {
> >>>>           if (mem_alloc_profiling_enabled())
> >>>> -               __pgalloc_tag_add(page, task, nr);
> >>>> +               __pgalloc_tag_add(page, task, nr, gfp_flags);
> >>>>    }
> >>>>
> >>>>    /* Should be called only if mem_alloc_profiling_enabled() */
> >>>> @@ -1341,7 +1344,7 @@ static inline void pgalloc_tag_sub_pages(struct alloc_tag *tag, unsigned int nr)
> >>>>    #else /* CONFIG_MEM_ALLOC_PROFILING */
> >>>>
> >>>>    static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,
> >>>> -                                  unsigned int nr) {}
> >>>> +                                  unsigned int nr, gfp_t gfp_flags) {}
> >>>>    static inline void pgalloc_tag_sub(struct page *page, unsigned int nr) {}
> >>>>    static inline void pgalloc_tag_sub_pages(struct alloc_tag *tag, unsigned int nr) {}
> >>>>
> >>>> @@ -1896,7 +1899,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
> >>>>
> >>>>           set_page_owner(page, order, gfp_flags);
> >>>>           page_table_check_alloc(page, order);
> >>>> -       pgalloc_tag_add(page, current, 1 << order);
> >>>> +       pgalloc_tag_add(page, current, 1 << order, gfp_flags);
> >>>>    }
> >>>>
> >>>>    static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
> >>>> --
> >>>> 2.25.1
> >>>>