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Tue, 11 Feb 2025 00:31:14 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.88.129]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id EA485180035E; Tue, 11 Feb 2025 00:31:04 +0000 (UTC) From: Nico Pache To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-mm@kvack.org Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, srivatsa@csail.mit.edu, haowenchao22@gmail.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, wangkefeng.wang@huawei.com, ziy@nvidia.com, jglisse@google.com, surenb@google.com, vishal.moola@gmail.com, zokeefe@google.com, zhengqi.arch@bytedance.com, jhubbard@nvidia.com, 21cnbao@gmail.com, willy@infradead.org, kirill.shutemov@linux.intel.com, david@redhat.com, aarcange@redhat.com, raquini@redhat.com, dev.jain@arm.com, sunnanyong@huawei.com, usamaarif642@gmail.com, audra@redhat.com, akpm@linux-foundation.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, tiwai@suse.de Subject: [RFC v2 1/9] introduce khugepaged_collapse_single_pmd to unify khugepaged and madvise_collapse Date: Mon, 10 Feb 2025 17:30:20 -0700 Message-ID: <20250211003028.213461-2-npache@redhat.com> In-Reply-To: <20250211003028.213461-1-npache@redhat.com> References: <20250211003028.213461-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 The khugepaged daemon and madvise_collapse have two different implementations that do almost the same thing. Create khugepaged_collapse_single_pmd to increase code reuse and create an entry point for future khugepaged changes. Refactor madvise_collapse and khugepaged_scan_mm_slot to use the new khugepaged_collapse_single_pmd function. Signed-off-by: Nico Pache --- mm/khugepaged.c | 96 +++++++++++++++++++++++++------------------------ 1 file changed, 50 insertions(+), 46 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 5f0be134141e..46faee67378b 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2365,6 +2365,52 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, } #endif +/* + * Try to collapse a single PMD starting at a PMD aligned addr, and return + * the results. + */ +static int khugepaged_collapse_single_pmd(unsigned long addr, struct mm_struct *mm, + struct vm_area_struct *vma, bool *mmap_locked, + struct collapse_control *cc) +{ + int result = SCAN_FAIL; + unsigned long tva_flags = cc->is_khugepaged ? TVA_ENFORCE_SYSFS : 0; + + if (!*mmap_locked) { + mmap_read_lock(mm); + *mmap_locked = true; + } + + if (thp_vma_allowable_order(vma, vma->vm_flags, + tva_flags, PMD_ORDER)) { + if (IS_ENABLED(CONFIG_SHMEM) && !vma_is_anonymous(vma)) { + struct file *file = get_file(vma->vm_file); + pgoff_t pgoff = linear_page_index(vma, addr); + + mmap_read_unlock(mm); + *mmap_locked = false; + result = hpage_collapse_scan_file(mm, addr, file, pgoff, + cc); + fput(file); + if (result == SCAN_PTE_MAPPED_HUGEPAGE) { + mmap_read_lock(mm); + if (hpage_collapse_test_exit_or_disable(mm)) + goto end; + result = collapse_pte_mapped_thp(mm, addr, + !cc->is_khugepaged); + mmap_read_unlock(mm); + } + } else { + result = hpage_collapse_scan_pmd(mm, vma, addr, + mmap_locked, cc); + } + if (result == SCAN_SUCCEED || result == SCAN_PMD_MAPPED) + ++khugepaged_pages_collapsed; + } +end: + return result; +} + static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, struct collapse_control *cc) __releases(&khugepaged_mm_lock) @@ -2439,33 +2485,9 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, VM_BUG_ON(khugepaged_scan.address < hstart || khugepaged_scan.address + HPAGE_PMD_SIZE > hend); - if (IS_ENABLED(CONFIG_SHMEM) && !vma_is_anonymous(vma)) { - struct file *file = get_file(vma->vm_file); - pgoff_t pgoff = linear_page_index(vma, - khugepaged_scan.address); - mmap_read_unlock(mm); - mmap_locked = false; - *result = hpage_collapse_scan_file(mm, - khugepaged_scan.address, file, pgoff, cc); - fput(file); - if (*result == SCAN_PTE_MAPPED_HUGEPAGE) { - mmap_read_lock(mm); - if (hpage_collapse_test_exit_or_disable(mm)) - goto breakouterloop; - *result = collapse_pte_mapped_thp(mm, - khugepaged_scan.address, false); - if (*result == SCAN_PMD_MAPPED) - *result = SCAN_SUCCEED; - mmap_read_unlock(mm); - } - } else { - *result = hpage_collapse_scan_pmd(mm, vma, - khugepaged_scan.address, &mmap_locked, cc); - } - - if (*result == SCAN_SUCCEED) - ++khugepaged_pages_collapsed; + *result = khugepaged_collapse_single_pmd(khugepaged_scan.address, + mm, vma, &mmap_locked, cc); /* move to next address */ khugepaged_scan.address += HPAGE_PMD_SIZE; @@ -2785,36 +2807,18 @@ int madvise_collapse(struct vm_area_struct *vma, struct vm_area_struct **prev, mmap_assert_locked(mm); memset(cc->node_load, 0, sizeof(cc->node_load)); nodes_clear(cc->alloc_nmask); - if (IS_ENABLED(CONFIG_SHMEM) && !vma_is_anonymous(vma)) { - struct file *file = get_file(vma->vm_file); - pgoff_t pgoff = linear_page_index(vma, addr); - mmap_read_unlock(mm); - mmap_locked = false; - result = hpage_collapse_scan_file(mm, addr, file, pgoff, - cc); - fput(file); - } else { - result = hpage_collapse_scan_pmd(mm, vma, addr, - &mmap_locked, cc); - } + result = khugepaged_collapse_single_pmd(addr, mm, vma, &mmap_locked, cc); + if (!mmap_locked) *prev = NULL; /* Tell caller we dropped mmap_lock */ -handle_result: switch (result) { case SCAN_SUCCEED: case SCAN_PMD_MAPPED: ++thps; break; case SCAN_PTE_MAPPED_HUGEPAGE: - BUG_ON(mmap_locked); - BUG_ON(*prev); - mmap_read_lock(mm); - result = collapse_pte_mapped_thp(mm, addr, true); - mmap_read_unlock(mm); - goto handle_result; - /* Whitelisted set of results where continuing OK */ case SCAN_PMD_NULL: case SCAN_PTE_NON_PRESENT: case SCAN_PTE_UFFD_WP: