From mboxrd@z Thu Jan 1 00:00:00 1970 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 B467C2FDC53; Mon, 8 Sep 2025 22:36:26 +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=1757370986; cv=none; b=IEoDiJ3uYblSXIyYKa6NlR90jZ6NxkVhkzve6iPSdG4HlechD0t/wy5pVNTu4dV8rgXpAFCgshWs3UUglWV3qxGrHL2Z2lAYHhXEKcaUkHi84fg51FiIDi8yvKdceQdlLIPE9VFanSsXUmwKiYd0Qvzf8o2AcICgG9kSPZkRxgs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757370986; c=relaxed/simple; bh=TAsGqH4DAOX0HTEIrw6xgKWHlm76GpSlCpJPhmPD4lc=; h=Date:To:From:Subject:Message-Id; b=M6DbJx/rZThDDeYYkq8jPs/3pfMtva1i0PACIhRx7Btq3QwaV/V++1qLP/rvk1q+PhShrtRSn2yKLvzYDfwevA8vhcoPPuXyopreQo28qqlbEoMF+wfGbQf/CFefiYnpFnkA+D1sQgNQjoSyrmNDHkdQ+LZMJ7i9jnbf9HtQqBk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=dYDEXL+i; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="dYDEXL+i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DCEDC4CEF1; Mon, 8 Sep 2025 22:36:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1757370986; bh=TAsGqH4DAOX0HTEIrw6xgKWHlm76GpSlCpJPhmPD4lc=; h=Date:To:From:Subject:From; b=dYDEXL+iyROp2UP7NBOubvv84tKdH4/A3TeyU9L+Eb4h7hpbKt3twN/m4x4MKWMO7 +GsI7AFPsiIaKm1npBN7ZgGZRQ3RsIv7BxesKgz6BwZl8bklRh9zLN1QruRK0EKo4E zYUFM47sFw+1UYPG9jKtGcvGdlVnwkcqRRT7WXtg= Date: Mon, 08 Sep 2025 15:36:25 -0700 To: mm-commits@vger.kernel.org,yuzhao@google.com,yuanchu@google.com,yangge1116@126.com,willy@infradead.org,will@kernel.org,weixugc@google.com,vbabka@suse.cz,stable@vger.kernel.org,shivankg@amd.com,riel@surriel.com,peterx@redhat.com,lizhe.67@bytedance.com,koct9i@gmail.com,keirf@google.com,jhubbard@nvidia.com,jgg@ziepe.ca,hch@infradead.org,hannes@cmpxchg.org,david@redhat.com,chrisl@kernel.org,axelrasmussen@google.com,aneesh.kumar@kernel.org,hughd@google.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-revert-mm-gup-clear-the-lru-flag-of-a-page-before-adding-to-lru-batch.patch added to mm-hotfixes-unstable branch Message-Id: <20250908223626.5DCEDC4CEF1@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: Revert "mm/gup: clear the LRU flag of a page before adding to LRU batch" has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-revert-mm-gup-clear-the-lru-flag-of-a-page-before-adding-to-lru-batch.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-revert-mm-gup-clear-the-lru-flag-of-a-page-before-adding-to-lru-batch.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Hugh Dickins Subject: mm: Revert "mm/gup: clear the LRU flag of a page before adding to LRU batch" Date: Mon, 8 Sep 2025 15:19:17 -0700 (PDT) This reverts commit 33dfe9204f29: now that collect_longterm_unpinnable_folios() is checking ref_count instead of lru, and mlock/munlock do not participate in the revised LRU flag clearing, those changes are misleading, and enlarge the window during which mlock/munlock may miss an mlock_count update. It is possible (I'd hesitate to claim probable) that the greater likelihood of missed mlock_count updates would explain the "Realtime threads delayed due to kcompactd0" observed on 6.12 in the Link below. If that is the case, this reversion will help; but a complete solution needs also a further patch, beyond the scope of this series. Included some 80-column cleanup around folio_batch_add_and_move(). The role of folio_test_clear_lru() (before taking per-memcg lru_lock) is questionable since 6.13 removed mem_cgroup_move_account() etc; but perhaps there are still some races which need it - not examined here. Link: https://lore.kernel.org/linux-mm/DU0PR01MB10385345F7153F334100981888259A@DU0PR01MB10385.eurprd01.prod.exchangelabs.com/ Link: https://lkml.kernel.org/r/05905d7b-ed14-68b1-79d8-bdec30367eba@google.com Signed-off-by: Hugh Dickins Acked-by: David Hildenbrand Cc: "Aneesh Kumar K.V" Cc: Axel Rasmussen Cc: Chris Li Cc: Christoph Hellwig Cc: Jason Gunthorpe Cc: Johannes Weiner Cc: John Hubbard Cc: Keir Fraser Cc: Konstantin Khlebnikov Cc: Li Zhe Cc: Matthew Wilcox (Oracle) Cc: Peter Xu Cc: Rik van Riel Cc: Shivank Garg Cc: Vlastimil Babka Cc: Wei Xu Cc: Will Deacon Cc: yangge Cc: Yuanchu Xie Cc: Yu Zhao Cc: Signed-off-by: Andrew Morton --- mm/swap.c | 50 ++++++++++++++++++++++++++------------------------ 1 file changed, 26 insertions(+), 24 deletions(-) --- a/mm/swap.c~mm-revert-mm-gup-clear-the-lru-flag-of-a-page-before-adding-to-lru-batch +++ a/mm/swap.c @@ -164,6 +164,10 @@ static void folio_batch_move_lru(struct for (i = 0; i < folio_batch_count(fbatch); i++) { struct folio *folio = fbatch->folios[i]; + /* block memcg migration while the folio moves between lru */ + if (move_fn != lru_add && !folio_test_clear_lru(folio)) + continue; + folio_lruvec_relock_irqsave(folio, &lruvec, &flags); move_fn(lruvec, folio); @@ -176,14 +180,10 @@ static void folio_batch_move_lru(struct } static void __folio_batch_add_and_move(struct folio_batch __percpu *fbatch, - struct folio *folio, move_fn_t move_fn, - bool on_lru, bool disable_irq) + struct folio *folio, move_fn_t move_fn, bool disable_irq) { unsigned long flags; - if (on_lru && !folio_test_clear_lru(folio)) - return; - folio_get(folio); if (disable_irq) @@ -191,8 +191,8 @@ static void __folio_batch_add_and_move(s else local_lock(&cpu_fbatches.lock); - if (!folio_batch_add(this_cpu_ptr(fbatch), folio) || folio_test_large(folio) || - lru_cache_disabled()) + if (!folio_batch_add(this_cpu_ptr(fbatch), folio) || + folio_test_large(folio) || lru_cache_disabled()) folio_batch_move_lru(this_cpu_ptr(fbatch), move_fn); if (disable_irq) @@ -201,13 +201,13 @@ static void __folio_batch_add_and_move(s local_unlock(&cpu_fbatches.lock); } -#define folio_batch_add_and_move(folio, op, on_lru) \ - __folio_batch_add_and_move( \ - &cpu_fbatches.op, \ - folio, \ - op, \ - on_lru, \ - offsetof(struct cpu_fbatches, op) >= offsetof(struct cpu_fbatches, lock_irq) \ +#define folio_batch_add_and_move(folio, op) \ + __folio_batch_add_and_move( \ + &cpu_fbatches.op, \ + folio, \ + op, \ + offsetof(struct cpu_fbatches, op) >= \ + offsetof(struct cpu_fbatches, lock_irq) \ ) static void lru_move_tail(struct lruvec *lruvec, struct folio *folio) @@ -231,10 +231,10 @@ static void lru_move_tail(struct lruvec void folio_rotate_reclaimable(struct folio *folio) { if (folio_test_locked(folio) || folio_test_dirty(folio) || - folio_test_unevictable(folio)) + folio_test_unevictable(folio) || !folio_test_lru(folio)) return; - folio_batch_add_and_move(folio, lru_move_tail, true); + folio_batch_add_and_move(folio, lru_move_tail); } void lru_note_cost_unlock_irq(struct lruvec *lruvec, bool file, @@ -328,10 +328,11 @@ static void folio_activate_drain(int cpu void folio_activate(struct folio *folio) { - if (folio_test_active(folio) || folio_test_unevictable(folio)) + if (folio_test_active(folio) || folio_test_unevictable(folio) || + !folio_test_lru(folio)) return; - folio_batch_add_and_move(folio, lru_activate, true); + folio_batch_add_and_move(folio, lru_activate); } #else @@ -507,7 +508,7 @@ void folio_add_lru(struct folio *folio) lru_gen_in_fault() && !(current->flags & PF_MEMALLOC)) folio_set_active(folio); - folio_batch_add_and_move(folio, lru_add, false); + folio_batch_add_and_move(folio, lru_add); } EXPORT_SYMBOL(folio_add_lru); @@ -685,13 +686,13 @@ void lru_add_drain_cpu(int cpu) void deactivate_file_folio(struct folio *folio) { /* Deactivating an unevictable folio will not accelerate reclaim */ - if (folio_test_unevictable(folio)) + if (folio_test_unevictable(folio) || !folio_test_lru(folio)) return; if (lru_gen_enabled() && lru_gen_clear_refs(folio)) return; - folio_batch_add_and_move(folio, lru_deactivate_file, true); + folio_batch_add_and_move(folio, lru_deactivate_file); } /* @@ -704,13 +705,13 @@ void deactivate_file_folio(struct folio */ void folio_deactivate(struct folio *folio) { - if (folio_test_unevictable(folio)) + if (folio_test_unevictable(folio) || !folio_test_lru(folio)) return; if (lru_gen_enabled() ? lru_gen_clear_refs(folio) : !folio_test_active(folio)) return; - folio_batch_add_and_move(folio, lru_deactivate, true); + folio_batch_add_and_move(folio, lru_deactivate); } /** @@ -723,10 +724,11 @@ void folio_deactivate(struct folio *foli void folio_mark_lazyfree(struct folio *folio) { if (!folio_test_anon(folio) || !folio_test_swapbacked(folio) || + !folio_test_lru(folio) || folio_test_swapcache(folio) || folio_test_unevictable(folio)) return; - folio_batch_add_and_move(folio, lru_lazyfree, true); + folio_batch_add_and_move(folio, lru_lazyfree); } void lru_add_drain(void) _ Patches currently in -mm which might be from hughd@google.com are mm-gup-check-ref_count-instead-of-lru-before-migration.patch mm-gup-local-lru_add_drain-to-avoid-lru_add_drain_all.patch mm-revert-mm-gup-clear-the-lru-flag-of-a-page-before-adding-to-lru-batch.patch mm-revert-mm-vmscanc-fix-oom-on-swap-stress-test.patch mm-folio_may_be_lru_cached-unless-folio_test_large.patch mm-lru_add_drain_all-do-local-lru_add_drain-first.patch