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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky Subject: [PATCHv2] mm: khugepaged: make scan loops suspend aware Date: Wed, 11 Feb 2026 12:15:00 +0900 Message-ID: <20260211031512.261127-1-senozhatsky@chromium.org> X-Mailer: git-send-email 2.53.0.239.g8d8fc8a987-goog 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" A number of khugepaaged's loops, e.g. khugepaged_scan_mm_slot(), are time unbound, which can become problematic during system suspend: PM: suspend entry (s2idle) Filesystems sync: 0.003 seconds Freezing user space processes Freezing user space processes completed (elapsed 0.003 seconds) OOM killer disabled. Freezing remaining freezable tasks Freezing remaining freezable tasks failed after 20.004 seconds (1 tasks ref= using to freeze, wq_busy=3D0): task:khugepaged state:D stack:0 pid:1345 ppid:2 flags:0x0000= 4000 Call Trace: schedule+0x523/0x16a0 schedule_timeout+0x23b/0x6e0 io_schedule_timeout+0x3f/0x80 wait_for_completion_io_timeout+0xe4/0x170 submit_bio_wait+0x79/0xc0 swap_readpage+0x150/0x2d0 swap_cluster_readahead+0x3be/0x750 shmem_swapin+0xa7/0x100 shmem_swapin_folio+0xcd/0x2e0 shmem_get_folio+0x237/0x580 collapse_file+0x247/0x1280 hpage_collapse_scan_file+0x26e/0x380 khugepaged+0x43b/0x810 kthread+0xfb/0x120 Make hpage_collapse_test_exit_or_disable() suspend aware so that khugepaaged's scan loops can terminate in a timely manner and let system enter the sleep state. Co-developed-by: Baolin Wang Signed-off-by: Sergey Senozhatsky --- v1->v2: Actually pass "cc" to hpage_collapse_test_exit_or_disable() mm/khugepaged.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index eff9e3061925..d32a5ad27097 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -392,10 +392,18 @@ static inline int hpage_collapse_test_exit(struct mm_= struct *mm) return atomic_read(&mm->mm_users) =3D=3D 0; } =20 -static inline int hpage_collapse_test_exit_or_disable(struct mm_struct *mm) +static inline int hpage_collapse_test_exit_or_disable(struct mm_struct *mm, + struct collapse_control *cc) { + bool was_frozen =3D false; + + if (cc->is_khugepaged && + unlikely(kthread_freezable_should_stop(&was_frozen))) + return 1; + return hpage_collapse_test_exit(mm) || - mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm); + mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm) || + was_frozen; } =20 static bool hugepage_pmd_enabled(void) @@ -895,7 +903,7 @@ static enum scan_result hugepage_vma_revalidate(struct = mm_struct *mm, unsigned l enum tva_type type =3D cc->is_khugepaged ? TVA_KHUGEPAGED : TVA_FORCED_COLLAPSE; =20 - if (unlikely(hpage_collapse_test_exit_or_disable(mm))) + if (unlikely(hpage_collapse_test_exit_or_disable(mm, cc))) return SCAN_ANY_PROCESS; =20 *vmap =3D vma =3D find_vma(mm, address); @@ -2420,7 +2428,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned = int pages, enum scan_result goto breakouterloop_mmap_lock; =20 progress++; - if (unlikely(hpage_collapse_test_exit_or_disable(mm))) + if (unlikely(hpage_collapse_test_exit_or_disable(mm, cc))) goto breakouterloop; =20 vma_iter_init(&vmi, mm, khugepaged_scan.address); @@ -2428,7 +2436,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned = int pages, enum scan_result unsigned long hstart, hend; =20 cond_resched(); - if (unlikely(hpage_collapse_test_exit_or_disable(mm))) { + if (unlikely(hpage_collapse_test_exit_or_disable(mm, cc))) { progress++; break; } @@ -2450,7 +2458,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned = int pages, enum scan_result bool mmap_locked =3D true; =20 cond_resched(); - if (unlikely(hpage_collapse_test_exit_or_disable(mm))) + if (unlikely(hpage_collapse_test_exit_or_disable(mm, cc))) goto breakouterloop; =20 VM_BUG_ON(khugepaged_scan.address < hstart || @@ -2468,7 +2476,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned = int pages, enum scan_result fput(file); if (*result =3D=3D SCAN_PTE_MAPPED_HUGEPAGE) { mmap_read_lock(mm); - if (hpage_collapse_test_exit_or_disable(mm)) + if (hpage_collapse_test_exit_or_disable(mm, cc)) goto breakouterloop; *result =3D try_collapse_pte_mapped_thp(mm, khugepaged_scan.address, false); --=20 2.53.0.239.g8d8fc8a987-goog