From nobody Sat Feb 7 14:34:29 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8518319DF48 for ; Fri, 4 Apr 2025 21:07:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743800829; cv=none; b=jxfktDmtLK+z1AjD24CLl3wPj4HaVuV/eATMmXEjuHaadsG5oYWUcQ4gVTNKZGFhZX2FWK7qI4wboCOIV0EJjR8xo9OqbPKNxzCVJWoKttkTTc86pRvsGk4LJpYzHWqDxxGI6kzsGubV31rdPf3bR9+iNOAfEP+17V7qe6Ptr0E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743800829; c=relaxed/simple; bh=x25eIUo6VkYoCUtqxJ6hHhPHU0LH2iMLq4u6rDb9zDQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Ah+XThd89s+TgoAee3+M7GrJo1xChwXj1PD7Gh9+vnvdSPEzicqdV9Q+eay1czcFd5ydxfFXtza3sxw56hbXEZwgUnnoLesyxnwhkK261Px0cBk9+S58l4PbZL/SFtc1Tw0IL+j5/9JJbRWe+sBJfU7SxjjG02Roa6iQvHEPzbc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HjPrYRhr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HjPrYRhr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE601C4CEDD; Fri, 4 Apr 2025 21:07:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743800828; bh=x25eIUo6VkYoCUtqxJ6hHhPHU0LH2iMLq4u6rDb9zDQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HjPrYRhr9Z7oTIv0r/O7mTYr2szq9bcvmUiqSzHwAamexSCI1B7OB5tAvTdgqr0XR r4iSWr7knMRVGPyCELhZTjQ0tUwZ11hqg76RYMy9LVzWdswC/c+ylC/P0JHcQLFSDG E9IbbpFZufhnMH1G0a39KdFFJVp0bjta7evjxrdnBXqW8BEwyzF9j3iAN/GWwG/zLI hdo8SNtiKK2HZYRGX+Be77WnsEYlwaiUr8SVsIX8mJXlP0+UJhNsbTxNvLmdTrhcQT GO/1FlgMgpcnvX1R5vu+kp5GhVqW6w9Hn4uaLTZGaIXSyzda+5QCKU7+A7trNNM8sZ PN6QwXfiSmTqw== From: SeongJae Park To: Andrew Morton Cc: SeongJae Park , "Liam R.Howlett" , David Hildenbrand , Lorenzo Stoakes , Rik van Riel , Shakeel Butt , Vlastimil Babka , kernel-team@meta.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2 2/4] mm/madvise: batch tlb flushes for MADV_FREE Date: Fri, 4 Apr 2025 14:06:58 -0700 Message-Id: <20250404210700.2156-3-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250404210700.2156-1-sj@kernel.org> References: <20250404210700.2156-1-sj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" MADV_FREE handling for [process_]madvise() flushes tlb for each vma of each address range. Update the logic to do tlb flushes in a batched way. Initialize an mmu_gather object from do_madvise() and vector_madvise(), which are the entry level functions for [process_]madvise(), respectively. And pass those objects to the function for per-vma work, via madvise_behavior struct. Make the per-vma logic not flushes tlb on their own but just saves the tlb entries to the received mmu_gather object. Finally, the entry level functions flush the tlb entries that gathered for the entire user request, at once. Signed-off-by: SeongJae Park Reviewed-by: Lorenzo Stoakes --- mm/madvise.c | 59 +++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 47 insertions(+), 12 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 8bcfdd995d18..564095e381b2 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -799,12 +799,13 @@ static const struct mm_walk_ops madvise_free_walk_ops= =3D { .walk_lock =3D PGWALK_RDLOCK, }; =20 -static int madvise_free_single_vma(struct vm_area_struct *vma, - unsigned long start_addr, unsigned long end_addr) +static int madvise_free_single_vma( + struct madvise_behavior *behavior, struct vm_area_struct *vma, + unsigned long start_addr, unsigned long end_addr) { struct mm_struct *mm =3D vma->vm_mm; struct mmu_notifier_range range; - struct mmu_gather tlb; + struct mmu_gather *tlb =3D behavior->tlb; =20 /* MADV_FREE works for only anon vma at the moment */ if (!vma_is_anonymous(vma)) @@ -820,17 +821,14 @@ static int madvise_free_single_vma(struct vm_area_str= uct *vma, range.start, range.end); =20 lru_add_drain(); - tlb_gather_mmu(&tlb, mm); update_hiwater_rss(mm); =20 mmu_notifier_invalidate_range_start(&range); - tlb_start_vma(&tlb, vma); + tlb_start_vma(tlb, vma); walk_page_range(vma->vm_mm, range.start, range.end, - &madvise_free_walk_ops, &tlb); - tlb_end_vma(&tlb, vma); + &madvise_free_walk_ops, tlb); + tlb_end_vma(tlb, vma); mmu_notifier_invalidate_range_end(&range); - tlb_finish_mmu(&tlb); - return 0; } =20 @@ -953,7 +951,7 @@ static long madvise_dontneed_free(struct vm_area_struct= *vma, if (action =3D=3D MADV_DONTNEED || action =3D=3D MADV_DONTNEED_LOCKED) return madvise_dontneed_single_vma(vma, start, end); else if (action =3D=3D MADV_FREE) - return madvise_free_single_vma(vma, start, end); + return madvise_free_single_vma(behavior, vma, start, end); else return -EINVAL; } @@ -1626,6 +1624,29 @@ static void madvise_unlock(struct mm_struct *mm, int= behavior) mmap_read_unlock(mm); } =20 +static bool madvise_batch_tlb_flush(int behavior) +{ + switch (behavior) { + case MADV_FREE: + return true; + default: + return false; + } +} + +static void madvise_init_tlb(struct madvise_behavior *madv_behavior, + struct mm_struct *mm) +{ + if (madvise_batch_tlb_flush(madv_behavior->behavior)) + tlb_gather_mmu(madv_behavior->tlb, mm); +} + +static void madvise_finish_tlb(struct madvise_behavior *madv_behavior) +{ + if (madvise_batch_tlb_flush(madv_behavior->behavior)) + tlb_finish_mmu(madv_behavior->tlb); +} + static bool is_valid_madvise(unsigned long start, size_t len_in, int behav= ior) { size_t len; @@ -1782,14 +1803,20 @@ static int madvise_do_behavior(struct mm_struct *mm, int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, i= nt behavior) { int error; - struct madvise_behavior madv_behavior =3D {.behavior =3D behavior}; + struct mmu_gather tlb; + struct madvise_behavior madv_behavior =3D { + .behavior =3D behavior, + .tlb =3D &tlb, + }; =20 if (madvise_should_skip(start, len_in, behavior, &error)) return error; error =3D madvise_lock(mm, behavior); if (error) return error; + madvise_init_tlb(&madv_behavior, mm); error =3D madvise_do_behavior(mm, start, len_in, &madv_behavior); + madvise_finish_tlb(&madv_behavior); madvise_unlock(mm, behavior); =20 return error; @@ -1806,13 +1833,18 @@ static ssize_t vector_madvise(struct mm_struct *mm,= struct iov_iter *iter, { ssize_t ret =3D 0; size_t total_len; - struct madvise_behavior madv_behavior =3D {.behavior =3D behavior}; + struct mmu_gather tlb; + struct madvise_behavior madv_behavior =3D { + .behavior =3D behavior, + .tlb =3D &tlb, + }; =20 total_len =3D iov_iter_count(iter); =20 ret =3D madvise_lock(mm, behavior); if (ret) return ret; + madvise_init_tlb(&madv_behavior, mm); =20 while (iov_iter_count(iter)) { unsigned long start =3D (unsigned long)iter_iov_addr(iter); @@ -1841,14 +1873,17 @@ static ssize_t vector_madvise(struct mm_struct *mm,= struct iov_iter *iter, } =20 /* Drop and reacquire lock to unwind race. */ + madvise_finish_tlb(&madv_behavior); madvise_unlock(mm, behavior); madvise_lock(mm, behavior); + madvise_init_tlb(&madv_behavior, mm); continue; } if (ret < 0) break; iov_iter_advance(iter, iter_iov_len(iter)); } + madvise_finish_tlb(&madv_behavior); madvise_unlock(mm, behavior); =20 ret =3D (total_len - iov_iter_count(iter)) ? : ret; --=20 2.39.5