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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 1467F4000B X-Stat-Signature: uoan8oboesiecbnb5ijygp4gfpepnqwy X-Rspam-User: X-HE-Tag: 1706516399-332284 X-HE-Meta: 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 53XBxcQq Ug+MP6D8w94rgzcPQimkD9lHd+1RfFJ3Sus5fZary1fj1mzSr9UIL7RjtV8aTDHaMAWgpUT2VmMNLi4oI/7OYHsy/pUQ6kJYhMRQKvh8MWWYCZ4ux4Be2e/Py/F2loY9FjkmhzT8MbxjhS32osmA4L2/l0hhaUmmTjJDH65eHYD+yp30wqDEAxtjK/7D0VPROr3W+Yhp+riUs5PoiR3uTlpPAdDObY3R40UWDKyC4tIwU3LZpKsmhprdcCX/JwzCx8INi X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/25/24 22:12, Alexandru Elisei wrote: > The arm64 MTE code uses the PG_arch_2 page flag, which it renames to > PG_mte_tagged, to track if a page has been mapped with tagging enabled. > That flag is cleared by free_pages_prepare() by doing: > > page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; > > When tag storage management is added, tag storage will be reserved for a > page if and only if the page is mapped as tagged (the page flag > PG_mte_tagged is set). When a page is freed, likewise, the code will have > to look at the the page flags to determine if the page has tag storage > reserved, which should also be freed. > > For this purpose, add an arch_free_pages_prepare() hook that is called > before that page flags are cleared. The function arch_free_page() has also > been considered for this purpose, but it is called after the flags are > cleared. arch_free_pages_prepare() makes sense as a prologue to arch_free_page(). s/arch_free_pages_prepare/arch_free_page_prepare to match similar functions. > > Signed-off-by: Alexandru Elisei > --- > > Changes since rfc v2: > > * Expanded commit message (David Hildenbrand). > > include/linux/pgtable.h | 4 ++++ > mm/page_alloc.c | 1 + > 2 files changed, 5 insertions(+) > > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > index f6d0e3513948..6d98d5fdd697 100644 > --- a/include/linux/pgtable.h > +++ b/include/linux/pgtable.h > @@ -901,6 +901,10 @@ static inline void arch_do_swap_page(struct mm_struct *mm, > } > #endif > > +#ifndef __HAVE_ARCH_FREE_PAGES_PREPARE I guess new __HAVE_ARCH_ constructs are not being added lately. Instead something like '#ifndef arch_free_pages_prepare' might be better suited. > +static inline void arch_free_pages_prepare(struct page *page, int order) { } > +#endif > + > #ifndef __HAVE_ARCH_UNMAP_ONE > /* > * Some architectures support metadata associated with a page. When a > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 2c140abe5ee6..27282a1c82fe 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1092,6 +1092,7 @@ static __always_inline bool free_pages_prepare(struct page *page, > > trace_mm_page_free(page, order); > kmsan_free_page(page, order); > + arch_free_pages_prepare(page, order); > > if (memcg_kmem_online() && PageMemcgKmem(page)) > __memcg_kmem_uncharge_page(page, order);