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[80.230.25.21]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488fb7bf696sm89203495e9.32.2026.04.20.05.50.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Apr 2026 05:50:40 -0700 (PDT) Date: Mon, 20 Apr 2026 08:50:38 -0400 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Andrew Morton , David Hildenbrand , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , linux-mm@kvack.org, virtualization@lists.linux.dev, Johannes Weiner , Zi Yan , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport Subject: [PATCH RFC v2 07/18] mm: post_alloc_hook: use PG_zeroed to skip zeroing, return pghint_t Message-ID: References: MIME-Version: 1.0 In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: XIGqCKfAUiV4RlgEXGleqNZPxWyDurTWPx6c5wO1Uxg_1776689442 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Rspamd-Server: rspam10 X-Stat-Signature: n7ssezxj5apbf995yya7znp6rhps4c76 X-Rspam-User: X-Rspamd-Queue-Id: EF87320003 X-HE-Tag: 1776689444-542792 X-HE-Meta: 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 KDQLrnBG Axu2afDJ62cZ3l7VHg1yqDacm6x7tpnEKCfLjBbjc3IH6taW6nEqgmRyrBDswNTiniEnV/TH1C3kkbUbbkcSOcwuPOYIW/gFjIOJenHCFv0wd3pNNiAzntQNpl58xFBpF3yqTuFYi6C5sH6I7E+Ydud6NhFesPGhenTZXmkvOWdlOx/ruk7H6AZgN/9dbDhbmoqy+HjA6W10q3wUasAe6N5R9Pcih7T39Jx+qKXjHpe9Bav1qMZVr+gIL/k3C/1km75KSIbRDaECUVg6GiKJybOWnbRzA36mnvWbdT35hkRXSvhYoYidiJhKC6uwHZ581XR7kk65gnErjaKq/nOdxxQuB2UTVVTEvNk+2DzRwplVKu101OUGKVuYGxQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Add pghint_t *hints parameter to post_alloc_hook() and prep_new_page(). post_alloc_hook() reads PageZeroed, clears it, and returns PGHINT_ZEROED via hints. This provides a single point where PG_zeroed is consumed and cleared, regardless of whether the page came through PCP or buddy. The flag is set in page_del_and_expand() and survives both paths until post_alloc_hook() consumes it. Only get_page_from_freelist() passes hints through prep_new_page(); all other callers (compaction, bulk alloc, split, contig) pass NULL. Signed-off-by: Michael S. Tsirkin Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- mm/compaction.c | 4 ++-- mm/internal.h | 3 ++- mm/page_alloc.c | 25 +++++++++++++++++-------- 3 files changed, 21 insertions(+), 11 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 1e8f8eca318c..6fcce7756613 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -82,7 +82,7 @@ static inline bool is_via_compact_memory(int order) { return false; } 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, NULL); set_page_refcounted(page); return page; } @@ -1833,7 +1833,7 @@ static struct folio *compaction_alloc_noprof(struct folio *src, unsigned long da } dst = (struct folio *)freepage; - post_alloc_hook(&dst->page, order, __GFP_MOVABLE); + post_alloc_hook(&dst->page, order, __GFP_MOVABLE, NULL); set_page_refcounted(&dst->page); if (order) prep_compound_page(&dst->page, order); diff --git a/mm/internal.h b/mm/internal.h index 686667b956c0..2964cdfcd31f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -887,7 +887,8 @@ static inline void prep_compound_tail(struct page *head, int tail_idx) set_page_private(p, 0); } -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, + pghint_t *hints); extern bool free_pages_prepare(struct page *page, unsigned int order); extern int user_min_free_kbytes; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ece61d02ea96..a4cfd645599a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1863,13 +1863,21 @@ static inline bool should_skip_init(gfp_t flags) } inline void post_alloc_hook(struct page *page, unsigned int order, - gfp_t gfp_flags) + gfp_t gfp_flags, pghint_t *hints) { bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) && !should_skip_init(gfp_flags); bool zero_tags = init && (gfp_flags & __GFP_ZEROTAGS); + bool zeroed = PageZeroed(page); int i; + __ClearPageZeroed(page); + if (hints) + *hints = zeroed ? PGHINT_ZEROED : 0; + + if (zeroed && !zero_tags) + init = false; + set_page_private(page, 0); arch_alloc_page(page, order); @@ -1918,9 +1926,9 @@ inline void post_alloc_hook(struct page *page, unsigned int order, } static void prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags, - unsigned int alloc_flags) + unsigned int alloc_flags, pghint_t *hints) { - post_alloc_hook(page, order, gfp_flags); + post_alloc_hook(page, order, gfp_flags, hints); if (order && (gfp_flags & __GFP_COMP)) prep_compound_page(page, order); @@ -3991,7 +3999,8 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, page = rmqueue(zonelist_zone(ac->preferred_zoneref), zone, order, gfp_mask, alloc_flags, ac->migratetype); if (page) { - prep_new_page(page, order, gfp_mask, alloc_flags); + prep_new_page(page, order, gfp_mask, alloc_flags, + hints); /* * If this is a high-order atomic allocation then check @@ -4227,7 +4236,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, /* Prep a captured page if available */ if (page) - prep_new_page(page, order, gfp_mask, alloc_flags); + prep_new_page(page, order, gfp_mask, alloc_flags, NULL); /* Try get a page from the freelist if available */ if (!page) @@ -5223,7 +5232,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid, } nr_account++; - prep_new_page(page, 0, gfp, 0); + prep_new_page(page, 0, gfp, 0, NULL); set_page_refcounted(page); page_array[nr_populated++] = page; } @@ -6958,7 +6967,7 @@ static void split_free_frozen_pages(struct list_head *list, gfp_t gfp_mask) 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, NULL); if (!order) continue; @@ -7164,7 +7173,7 @@ int alloc_contig_frozen_range_noprof(unsigned long start, unsigned long end, 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, 0, NULL); } else { ret = -EINVAL; WARN(true, "PFN range: requested [%lu, %lu), allocated [%lu, %lu)\n", -- MST