+ mm-replace-__gfp_no_codetag-with-alloc_no_codetag.patch added to mm-new branch

+ mm-replace-__gfp_no_codetag-with-alloc_no_codetag.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: replace __GFP_NO_CODETAG with ALLOC_NO_CODETAG
has been added to the -mm mm-new branch.  Its filename is
     mm-replace-__gfp_no_codetag-with-alloc_no_codetag.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-replace-__gfp_no_codetag-with-alloc_no_codetag.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: Brendan Jackman <jackmanb@google.com>
Subject: mm: replace __GFP_NO_CODETAG with ALLOC_NO_CODETAG
Date: Fri, 03 Jul 2026 12:31:55 +0000

Now that alloc_pages has an entrypoint that allows passing alloc_flags, we
can take advantage of this to start removing GFP flags that are only used
for mm-internal stuff.

This requires also plumbing the alloc_flags into some more of the
allocator code, in particular __alloc_pages[_noprof]() gets an alloc_flags
arg to go along with its callees, and we now need to pass those flags
deeper into the allocator so they can reach the alloc_tag code.

While moving the flag definition into page_alloc.h, also update the
comment per Hao's suggestion.

No functional change intended.

Link: https://lore.kernel.org/all/b4916118-3537-4e19-8bc8-1d103dd0d225@linux.dev/
Link: https://lore.kernel.org/20260703-alloc-trylock-v5-15-c87b714e19d3@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Tested-by: Hao Ge <hao.ge@linux.dev>
Acked-by: Hao Ge <hao.ge@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/alloc_tag.h |    4 +-
 mm/alloc_tag.c            |   23 ++++-----------
 mm/compaction.c           |    4 +-
 mm/page_alloc.c           |   52 ++++++++++++++++++++----------------
 mm/page_alloc.h           |   14 ++++++++-
 mm/page_frag_cache.c      |    4 +-
 6 files changed, 55 insertions(+), 46 deletions(-)

--- a/include/linux/alloc_tag.h~mm-replace-__gfp_no_codetag-with-alloc_no_codetag
+++ a/include/linux/alloc_tag.h
@@ -163,11 +163,11 @@ static inline void alloc_tag_sub_check(u
 {
 	WARN_ONCE(ref && !ref->ct, "alloc_tag was not set\n");
 }
-void alloc_tag_add_early_pfn(unsigned long pfn, gfp_t gfp_flags);
+void alloc_tag_add_early_pfn(unsigned long pfn, unsigned int alloc_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, gfp_t gfp_flags) {}
+static inline void alloc_tag_add_early_pfn(unsigned long pfn, unsigned int alloc_flags) {}
 #endif
 
 /* Caller should verify both ref and tag to be valid */
--- a/mm/alloc_tag.c~mm-replace-__gfp_no_codetag-with-alloc_no_codetag
+++ a/mm/alloc_tag.c
@@ -15,6 +15,9 @@
 #include <linux/vmalloc.h>
 #include <linux/kmemleak.h>
 
+#include "internal.h"
+#include "page_alloc.h"
+
 #define ALLOCINFO_FILE_NAME		"allocinfo"
 #define MODULE_ALLOC_TAG_VMAP_SIZE	(100000UL * sizeof(struct alloc_tag))
 #define SECTION_START(NAME)		(CODETAG_SECTION_START_PREFIX NAME)
@@ -783,19 +786,6 @@ struct pfn_pool {
 
 #define PFN_POOL_SIZE			((PAGE_SIZE - offsetof(struct pfn_pool, pfns)) / \
 					 sizeof(unsigned long))
-
-/*
- * 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.
- *
- * 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.
- */
-#define __GFP_NO_CODETAG		__GFP_NO_OBJ_EXT
-
 static struct pfn_pool *current_pfn_pool __initdata;
 
 static void __init __alloc_tag_add_early_pfn(unsigned long pfn)
@@ -806,7 +796,8 @@ static void __init __alloc_tag_add_early
 	do {
 		pool = READ_ONCE(current_pfn_pool);
 		if (!pool || atomic_read(&pool->count) >= PFN_POOL_SIZE) {
-			struct page *new_page = alloc_page(__GFP_HIGH | __GFP_NO_CODETAG);
+			struct page *new_page = __alloc_pages(__GFP_HIGH, 0, numa_mem_id(),
+							      NULL, ALLOC_NO_CODETAG);
 			struct pfn_pool *new;
 
 			if (!new_page) {
@@ -837,7 +828,7 @@ typedef void alloc_tag_add_func(unsigned
 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, gfp_t gfp_flags)
+void alloc_tag_add_early_pfn(unsigned long pfn, unsigned int alloc_flags)
 {
 	alloc_tag_add_func *alloc_tag_add;
 
@@ -845,7 +836,7 @@ void alloc_tag_add_early_pfn(unsigned lo
 		return;
 
 	/* Skip allocations for the tracking list itself to avoid recursion. */
-	if (gfp_flags & __GFP_NO_CODETAG)
+	if (alloc_flags & ALLOC_NO_CODETAG)
 		return;
 
 	rcu_read_lock();
--- a/mm/compaction.c~mm-replace-__gfp_no_codetag-with-alloc_no_codetag
+++ a/mm/compaction.c
@@ -83,7 +83,7 @@ static inline bool is_via_compact_memory
 
 static struct page *mark_allocated_noprof(struct page *page, unsigned int order, gfp_t gfp_flags)
 {
-	post_alloc_hook(page, order, __GFP_MOVABLE);
+	post_alloc_hook(page, order, __GFP_MOVABLE, ALLOC_DEFAULT);
 	set_page_refcounted(page);
 	return page;
 }
@@ -1851,7 +1851,7 @@ again:
 	}
 	dst = (struct folio *)freepage;
 
-	post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
+	post_alloc_hook(&dst->page, order, __GFP_MOVABLE, ALLOC_DEFAULT);
 	set_page_refcounted(&dst->page);
 	if (order)
 		prep_compound_page(&dst->page, order);
--- a/mm/page_alloc.c~mm-replace-__gfp_no_codetag-with-alloc_no_codetag
+++ a/mm/page_alloc.c
@@ -1249,7 +1249,7 @@ void __clear_page_tag_ref(struct page *p
 /* 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, gfp_t gfp_flags)
+		       unsigned int nr, unsigned int alloc_flags)
 {
 	union pgtag_ref_handle handle;
 	union codetag_ref ref;
@@ -1263,17 +1263,17 @@ void __pgalloc_tag_add(struct page *page
 		 * 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), gfp_flags);
+		alloc_tag_add_early_pfn(page_to_pfn(page), alloc_flags);
 		if (task->alloc_tag)
 			alloc_tag_set_inaccurate(task->alloc_tag);
 	}
 }
 
 static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,
-				   unsigned int nr, gfp_t gfp_flags)
+				   unsigned int nr, unsigned int alloc_flags)
 {
 	if (mem_alloc_profiling_enabled())
-		__pgalloc_tag_add(page, task, nr, gfp_flags);
+		__pgalloc_tag_add(page, task, nr, alloc_flags);
 }
 
 /* Should be called only if mem_alloc_profiling_enabled() */
@@ -1306,7 +1306,7 @@ static inline void pgalloc_tag_sub_pages
 #else /* CONFIG_MEM_ALLOC_PROFILING */
 
 static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,
-				   unsigned int nr, gfp_t gfp_flags) {}
+				   unsigned int nr, unsigned int alloc_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) {}
 
@@ -1810,7 +1810,7 @@ static inline bool should_skip_init(gfp_
 }
 
 inline void post_alloc_hook(struct page *page, unsigned int order,
-				gfp_t gfp_flags)
+				gfp_t gfp_flags, unsigned int alloc_flags)
 {
 	const bool zero_tags = gfp_flags & __GFP_ZEROTAGS;
 	bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) &&
@@ -1861,13 +1861,13 @@ inline void post_alloc_hook(struct page
 
 	set_page_owner(page, order, gfp_flags);
 	page_table_check_alloc(page, order);
-	pgalloc_tag_add(page, current, 1 << order, gfp_flags);
+	pgalloc_tag_add(page, current, 1 << order, alloc_flags);
 }
 
 static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
 							unsigned int alloc_flags)
 {
-	post_alloc_hook(page, order, gfp_flags);
+	post_alloc_hook(page, order, gfp_flags, alloc_flags);
 
 	if (order && (gfp_flags & __GFP_COMP))
 		prep_compound_page(page, order);
@@ -4078,7 +4078,7 @@ __alloc_pages_may_oom(gfp_t gfp_mask, un
 	 */
 	page = get_page_from_freelist((gfp_mask | __GFP_HARDWALL) &
 				      ~__GFP_DIRECT_RECLAIM, order,
-				      ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
+				      ac->alloc_flags|ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
 	if (page)
 		goto out;
 
@@ -4124,7 +4124,7 @@ __alloc_pages_may_oom(gfp_t gfp_mask, un
 		 */
 		if (gfp_mask & __GFP_NOFAIL)
 			page = __alloc_pages_cpuset_fallback(gfp_mask, order,
-					ALLOC_NO_WATERMARKS, ac);
+					ac->alloc_flags|ALLOC_NO_WATERMARKS, ac);
 	}
 out:
 	mutex_unlock(&oom_lock);
@@ -4791,8 +4791,12 @@ restart:
 	 * The fast path uses conservative alloc_flags to succeed only until
 	 * kswapd needs to be woken up, and to avoid the cost of setting up
 	 * alloc_flags precisely. So we do that now.
+	 *
+	 * Can't just or alloc_flags if it contains WMARK bits, but those flags
+	 * shouldn't be set in ac->alloc_flags.
 	 */
-	alloc_flags = alloc_flags_slowpath(gfp_mask, order);
+	VM_WARN_ON(ac->alloc_flags & ALLOC_WMARK_MASK);
+	alloc_flags = ac->alloc_flags | alloc_flags_slowpath(gfp_mask, order);
 
 	/*
 	 * We need to recalculate the starting point for the zonelist iterator
@@ -4834,7 +4838,7 @@ retry:
 	reserve_flags = __gfp_pfmemalloc_flags(gfp_mask);
 	if (reserve_flags)
 		alloc_flags = alloc_flags_cma(gfp_mask, reserve_flags) |
-					  (alloc_flags & ALLOC_KSWAPD);
+				ac->alloc_flags | (alloc_flags & ALLOC_KSWAPD);
 
 	/*
 	 * Reset the nodemask and zonelist iterators if memory policies can be
@@ -5003,6 +5007,8 @@ nopage:
 	 * we always retry
 	 */
 	if (unlikely(nofail)) {
+		unsigned int alloc_flags = ac->alloc_flags | ALLOC_MIN_RESERVE;
+
 		/*
 		 * Lacking direct_reclaim we can't do anything to reclaim memory,
 		 * we disregard these unreasonable nofail requests and still
@@ -5018,7 +5024,7 @@ nopage:
 		 * could deplete whole memory reserves which would just make
 		 * the situation worse.
 		 */
-		page = __alloc_pages_cpuset_fallback(gfp_mask, order, ALLOC_MIN_RESERVE, ac);
+		page = __alloc_pages_cpuset_fallback(gfp_mask, order, alloc_flags, ac);
 		if (page)
 			goto got_pg;
 
@@ -5236,7 +5242,7 @@ out:
 	return nr_populated;
 
 failed:
-	page = __alloc_pages_noprof(gfp, 0, preferred_nid, nodemask);
+	page = __alloc_pages_noprof(gfp, 0, preferred_nid, nodemask, ALLOC_DEFAULT);
 	if (page)
 		page_array[nr_populated++] = page;
 	goto out;
@@ -5344,11 +5350,13 @@ struct page *__alloc_frozen_pages_noprof
 {
 	struct page *page;
 	gfp_t alloc_gfp; /* The gfp_t that was actually used for allocation */
-	struct alloc_context ac = { };
+	struct alloc_context ac = {
+		.alloc_flags = alloc_flags,
+	};
 	unsigned int fastpath_alloc_flags = alloc_flags;
 
 	/* Other flags could be supported later if needed. */
-	if (WARN_ON(alloc_flags & ~ALLOC_NOLOCK))
+	if (WARN_ON(alloc_flags & ~(ALLOC_NOLOCK | ALLOC_NO_CODETAG)))
 		return NULL;
 
 	if (!alloc_order_allowed(gfp, order, alloc_flags))
@@ -5421,12 +5429,12 @@ out:
 EXPORT_SYMBOL(__alloc_frozen_pages_noprof);
 
 struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order,
-		int preferred_nid, nodemask_t *nodemask)
+		int preferred_nid, nodemask_t *nodemask, unsigned int alloc_flags)
 {
 	struct page *page;
 
 	page = __alloc_frozen_pages_noprof(gfp, order, preferred_nid, nodemask,
-					   ALLOC_DEFAULT);
+					   alloc_flags);
 	if (page)
 		set_page_refcounted(page);
 	return page;
@@ -5440,7 +5448,7 @@ struct page *alloc_pages_node_noprof(int
 	VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
 	warn_if_node_offline(nid, gfp_mask);
 
-	return __alloc_pages_noprof(gfp_mask, order, nid, NULL);
+	return __alloc_pages_noprof(gfp_mask, order, nid, NULL, ALLOC_DEFAULT);
 }
 EXPORT_SYMBOL(alloc_pages_node_noprof);
 
@@ -5448,7 +5456,7 @@ struct folio *__folio_alloc_noprof(gfp_t
 		nodemask_t *nodemask)
 {
 	struct page *page = __alloc_pages_noprof(gfp | __GFP_COMP, order,
-					preferred_nid, nodemask);
+					preferred_nid, nodemask, ALLOC_DEFAULT);
 	return page_rmappable_folio(page);
 }
 EXPORT_SYMBOL(__folio_alloc_noprof);
@@ -7130,7 +7138,7 @@ static void split_free_frozen_pages(stru
 		list_for_each_entry_safe(page, next, &list[order], lru) {
 			int i;
 
-			post_alloc_hook(page, order, gfp_mask);
+			post_alloc_hook(page, order, gfp_mask, ALLOC_DEFAULT);
 			if (!order)
 				continue;
 
@@ -7335,7 +7343,7 @@ int alloc_contig_frozen_range_noprof(uns
 		struct page *head = pfn_to_page(start);
 
 		check_new_pages(head, order);
-		prep_new_page(head, order, gfp_mask, 0);
+		prep_new_page(head, order, gfp_mask, ALLOC_DEFAULT);
 	} else {
 		ret = -EINVAL;
 		WARN(true, "PFN range: requested [%lu, %lu), allocated [%lu, %lu)\n",
--- a/mm/page_alloc.h~mm-replace-__gfp_no_codetag-with-alloc_no_codetag
+++ a/mm/page_alloc.h
@@ -49,6 +49,13 @@
 #define ALLOC_HIGHATOMIC	0x200 /* Allows access to MIGRATE_HIGHATOMIC */
 #define ALLOC_NOLOCK		0x400 /* Only use spin_trylock in allocation path */
 #define ALLOC_KSWAPD		0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */
+/*
+ * Avoid alloc_tag recursion for internal allocations.
+ *
+ * Callers must clear_page_tag_ref() before freeing to avoid warnings from
+ * alloc_tag_sub_check().
+ */
+#define ALLOC_NO_CODETAG       0x1000
 
 /* Flags that allow allocations below the min watermark. */
 #define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM)
@@ -84,6 +91,8 @@ struct alloc_context {
 	 */
 	enum zone_type highest_zoneidx;
 	bool spread_dirty_pages;
+	/* Only flags that are global to the whole allocation go here. */
+	unsigned int alloc_flags;
 };
 
 /*
@@ -214,7 +223,8 @@ static inline struct page *pageblock_pfn
 extern void __free_pages_core(struct page *page, unsigned int order,
 		enum meminit_context context);
 
-void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags);
+void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags,
+		     unsigned int alloc_flags);
 extern bool free_pages_prepare(struct page *page, unsigned int order);
 
 extern int user_min_free_kbytes;
@@ -245,7 +255,7 @@ struct page *alloc_frozen_pages_nolock_n
 void free_frozen_pages_nolock(struct page *page, unsigned int order);
 
 struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order, int preferred_nid,
-		nodemask_t *nodemask);
+		nodemask_t *nodemask, unsigned int alloc_flags);
 #define __alloc_pages(...)			alloc_hooks(__alloc_pages_noprof(__VA_ARGS__))
 
 extern void zone_pcp_reset(struct zone *zone);
--- a/mm/page_frag_cache.c~mm-replace-__gfp_no_codetag-with-alloc_no_codetag
+++ a/mm/page_frag_cache.c
@@ -57,10 +57,10 @@ static struct page *__page_frag_cache_re
 	gfp_mask = (gfp_mask & ~__GFP_DIRECT_RECLAIM) |  __GFP_COMP |
 		   __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC;
 	page = __alloc_pages(gfp_mask, PAGE_FRAG_CACHE_MAX_ORDER,
-			     numa_mem_id(), NULL);
+			     numa_mem_id(), NULL, ALLOC_DEFAULT);
 #endif
 	if (unlikely(!page)) {
-		page = __alloc_pages(gfp, 0, numa_mem_id(), NULL);
+		page = __alloc_pages(gfp, 0, numa_mem_id(), NULL, ALLOC_DEFAULT);
 		order = 0;
 	}
 
_

Patches currently in -mm which might be from jackmanb@google.com are

mm-page_alloc-drop-flag-conversion-optimisation.patch
mm-secretmem-disable-under-highmem.patch
mm-page_alloc-rename-alloc_trylock-alloc_nolock.patch
mm-page_alloc-some-renames-to-clarify-alloc_flags-scopes.patch
mm-name-some-args-in-a-function-declaration.patch
mm-split-out-internal-page_alloch.patch
mm-page_alloc-unify-__alloc_frozen_pages_noprof.patch
mm-page_alloc-relax-gfp-warn-in-nolock-allocs.patch
mm-move-some-stuff-to-mm-page_alloch.patch
perf-x86-intel-use-higher-level-allocator-api.patch
kvm-vmx-use-higher-level-allocator-api.patch
x86-virt-use-higher-level-allocator-api.patch
sgi-xp-use-higher-level-allocator-api.patch
net-funeth-switch-to-higher-level-allocator-api.patch
mm-remove-__alloc_pages_node.patch
mm-move-__alloc_pages-to-mm-page_alloch.patch
mm-replace-__gfp_no_codetag-with-alloc_no_codetag.patch
mm-page_alloc-drop-alloc_flags-arg-from-alloc_flags_cma.patch
mm-factor-out-can_spin_trylock.patch