From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-145.mta1.migadu.com [95.215.58.145]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D434468C06 for ; Fri, 2 Oct 2026 09:57:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.145 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790935032; cv=none; b=IsvqFxNKnoMEzxrs8SJOZpyI5rvwzHhQOoIDjh9USVYVBvgis6lTsb5QEqGdrOr12rtP+Sub6b3xGoN6LMz7RreUHTzCwWu/E4vKAx0ihb6EPBQnxB+NQZsRIVdltvd0CplStgyZgmn2hMC+ovcwpw0b3qdMFtQaKS7rxf2Cz2A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790935032; c=relaxed/simple; bh=7cWRiY61ttsBLvX5i9ElmLypjZl7WDBKL9U4yzhj3UM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=f7gwIuf0wY4TZ7eky8AmsFZK0dCbrIlVODwACTN4CmjcHrtCp6/YKt1EuQ0EfVQBKsXbngNIj/6BjnSKr/m4vu8polgQW7vXf32/ObWVrpqxjxC2y+iRPPTFYhpLNOK7AsLpfKj2wFIrt3WFi3eWdFxZx2ZNSdNdDaKuKB+nzRc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=ms8P+k99; arc=none smtp.client-ip=95.215.58.145 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="ms8P+k99" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=7cWRiY61ttsBLvX5i9ElmLypjZl7WDBKL9U4yzhj3UM=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790935028; v=1; x=1791539828; b=ms8P+k99mL4Xm5d2JSr4KWzr5ADzTLyRHvqnZWLFRi+qbq6LtHEHQzT30/NQsWLysPHSlu2J 7rcgonHAR8/J27x64Ew1vIUJNQp8XDZttQUq9e0f6Ux4y+Y7Za8D2se7xP2CaKxwaC/wKlt6K7R ulCXxjMu8RGSQts99+zniTlA= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta11.migadu.com with ESMTPS id 0f29b55ffbe886d7; Fri, 02 Oct 2026 09:57:08 +0000 X-Mizu-Trace-ID: 0f29b55ffbe886d7 X-Migadu-Flow: FLOW_OUT From: Usama Arif To: Andrew Morton , david@kernel.org, chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, ziy@nvidia.com, linux-mm@kvack.org Cc: ying.huang@linux.alibaba.com, Baoquan He , willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr, kas@kernel.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, Nico Pache , Liam R. Howlett , ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, linux-kernel@vger.kernel.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, yosry@kernel.org, qi.zheng@linux.dev, luizcap@redhat.com, kernel-team@meta.com, Usama Arif Subject: [PATCH v8 20/30] mm/madvise: free PMD swap entries with MADV_FREE Date: Fri, 2 Oct 2026 02:52:34 -0700 Message-ID: <20261002095503.3585565-21-usama.arif@linux.dev> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261002095503.3585565-1-usama.arif@linux.dev> References: <20261002095503.3585565-1-usama.arif@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit madvise_free_pte_range() only calls madvise_free_huge_pmd() for a present THP, and its PTE loop cannot descend into a non-present PMD, so MADV_FREE over a swapped-out THP silently does nothing. Over the same range as PTE swap entries it frees every slot, which is what userspace gets today. Free it at PMD granularity when the advice covers the whole PMD, and split and let the PTE path handle the subrange when it does not. zap_deposited_table() moves above its new caller; it is otherwise unchanged. Signed-off-by: Usama Arif --- mm/huge_memory.c | 34 +++++++++++++++++++++++++--------- mm/madvise.c | 2 +- 2 files changed, 26 insertions(+), 10 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9cf7c4747cac9..c3d37dd84f523 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2424,6 +2424,15 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) return 0; } +static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) +{ + pgtable_t pgtable; + + pgtable = pgtable_trans_huge_withdraw(mm, pmd); + pte_free_defer(mm, pgtable); + mm_dec_nr_ptes(mm); +} + /* * Return true if we do MADV_FREE successfully on entire pmd page. * Otherwise, return false. @@ -2448,6 +2457,22 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, goto out; if (unlikely(!pmd_present(orig_pmd))) { + if (pmd_is_swap_entry(orig_pmd)) { + softleaf_t entry = softleaf_from_pmd(orig_pmd); + + if (next - addr != HPAGE_PMD_SIZE) { + spin_unlock(ptl); + __split_huge_pmd(vma, pmd, addr); + goto out_unlocked; + } + + pmdp_huge_get_and_clear(mm, addr, pmd); + zap_deposited_table(mm, pmd); + spin_unlock(ptl); + swap_put_entries_direct(entry, HPAGE_PMD_NR); + add_mm_counter(mm, MM_SWAPENTS, -HPAGE_PMD_NR); + return true; + } VM_WARN_ON_ONCE(!pmd_is_migration_entry(orig_pmd) && !pmd_is_device_private_entry(orig_pmd)); goto out; @@ -2502,15 +2527,6 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, return ret; } -static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) -{ - pgtable_t pgtable; - - pgtable = pgtable_trans_huge_withdraw(mm, pmd); - pte_free_defer(mm, pgtable); - mm_dec_nr_ptes(mm); -} - static void zap_huge_pmd_folio(struct mm_struct *mm, struct vm_area_struct *vma, pmd_t pmdval, struct folio *folio, bool is_present) { diff --git a/mm/madvise.c b/mm/madvise.c index fbb72ab49aa64..70acb39b8b3dd 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -678,7 +678,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, int nr, max_nr; next = pmd_addr_end(addr, end); - if (pmd_trans_huge(*pmd)) + if (pmd_trans_huge(*pmd) || pmd_is_swap_entry(*pmd)) if (madvise_free_huge_pmd(tlb, vma, pmd, addr, next)) return 0; -- 2.53.0-Meta