Commit be25d1d4 authored by Suren Baghdasaryan's avatar Suren Baghdasaryan Committed by Andrew Morton
Browse files

mm: create new codetag references during page splitting 

When a high-order page is split into smaller ones, each newly split page
should get its codetag.  After the split each split page will be
referencing the original codetag.  The codetag's "bytes" counter remains
the same because the amount of allocated memory has not changed, however
the "calls" counter gets increased to keep the counter correct when these
individual pages get freed.

Link: https://lkml.kernel.org/r/20240321163705.3067592-20-surenb@google.com


Signed-off-by: default avatarSuren Baghdasaryan <surenb@google.com>
Reviewed-by: default avatarVlastimil Babka <vbabka@suse.cz>
Tested-by: default avatarKees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent b951aaff

include/linux/alloc_tag.h

+9 −0
Original line number Diff line number Diff line
@@ -117,6 +117,15 @@ static inline void __alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag 
	this_cpu_inc(tag->counters->calls);

}



static inline void alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag)

{

	alloc_tag_add_check(ref, tag);

	if (!ref || !tag)

		return;



	__alloc_tag_ref_set(ref, tag);

}



static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag, size_t bytes)

{

	alloc_tag_add_check(ref, tag);

include/linux/pgalloc_tag.h

+30 −0
Original line number Diff line number Diff line
@@ -67,11 +67,41 @@ static inline void pgalloc_tag_sub(struct page *page, unsigned int nr) 
	}

}



static inline void pgalloc_tag_split(struct page *page, unsigned int nr)

{

	int i;

	struct page_ext *page_ext;

	union codetag_ref *ref;

	struct alloc_tag *tag;



	if (!mem_alloc_profiling_enabled())

		return;



	page_ext = page_ext_get(page);

	if (unlikely(!page_ext))

		return;



	ref = codetag_ref_from_page_ext(page_ext);

	if (!ref->ct)

		goto out;



	tag = ct_to_alloc_tag(ref->ct);

	page_ext = page_ext_next(page_ext);

	for (i = 1; i < nr; i++) {

		/* Set new reference to point to the original tag */

		alloc_tag_ref_set(codetag_ref_from_page_ext(page_ext), tag);

		page_ext = page_ext_next(page_ext);

	}

out:

	page_ext_put(page_ext);

}



#else /* CONFIG_MEM_ALLOC_PROFILING */



static inline void pgalloc_tag_add(struct page *page, struct task_struct *task,

				   unsigned int nr) {}

static inline void pgalloc_tag_sub(struct page *page, unsigned int nr) {}

static inline void pgalloc_tag_split(struct page *page, unsigned int nr) {}



#endif /* CONFIG_MEM_ALLOC_PROFILING */

mm/huge_memory.c

+2 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <linux/sched/sysctl.h>

#include <linux/memory-tiers.h>

#include <linux/compat.h>

#include <linux/pgalloc_tag.h>



#include <asm/tlb.h>

#include <asm/pgalloc.h>
@@ -2946,6 +2947,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, 
	/* Caller disabled irqs, so they are still disabled here */



	split_page_owner(head, order, new_order);

	pgalloc_tag_split(head, 1 << order);



	/* See comment in __split_huge_page_tail() */

	if (folio_test_anon(folio)) {

mm/page_alloc.c

+2 −0
Original line number Diff line number Diff line
@@ -2630,6 +2630,7 @@ void split_page(struct page *page, unsigned int order) 
	for (i = 1; i < (1 << order); i++)

		set_page_refcounted(page + i);

	split_page_owner(page, order, 0);

	pgalloc_tag_split(page, 1 << order);

	split_page_memcg(page, order, 0);

}

EXPORT_SYMBOL_GPL(split_page);
@@ -4827,6 +4828,7 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order, 
		struct page *last = page + nr;



		split_page_owner(page, order, 0);

		pgalloc_tag_split(page, 1 << order);

		split_page_memcg(page, order, 0);

		while (page < --last)

			set_page_refcounted(last);