From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8CAFA390C8A for ; Wed, 23 Sep 2026 02:43:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790131422; cv=none; b=AO/1ic1SuzW+UGC3e5mX+aL6hT6Vb7cdt7DppBJdwjqmhGbKINPUUpfZpAf5d9l5Vur31MTLKzltJDw21G+udd+BSV77CSEmlukcDMSKDqXjPBJrwWvT6rbh8EmutXy+qUW6Np1LS1wdbQAslGPWzg5UdyYGoh/i322ASFg0LIE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790131422; c=relaxed/simple; bh=JK2K0NvEz0itV4dWAfjjugcWgJVwF8gbcg8Xjul9Dcw=; h=Date:To:From:Subject:Message-Id; b=U1czTQKtyu+XpGwzeV9H/CLytMbJmpmXzu+stY/t0iSUp9bFokhFHr7GJFsRcPF9ijjw3MnfLCU8F0mnt0lER3pGH3gU1on+2M8ap7SsFh/tETdyqZVPAES81YB/LDN6FVt+NOjxlJXDHkz9upd+L5K8Uc6U+YbTyy1bGa6fnVs= 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=qhKUCwi8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="qhKUCwi8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2605E1F000FF; Wed, 23 Sep 2026 02:43:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1790131414; bh=6FWHXFfD01zr6bpltC6lUqEoPj34LFQ64kslquyNb8I=; h=Date:To:From:Subject; b=qhKUCwi8ZFGbO3XVcx/DkX0oR68IyY/x17eg2qtLI0plGYBBE+UCxM5C5C8HKXgOB WQyMmnEAZ+OzK8+CBRYseSBK7l4UXUHpVaxNevDc1GAWL65vFNeMOaAU2Mp4sABDEO YBIK04LRwkhGbMTZGoLZtNEBD34DriuEraedgGDE= Date: Tue, 22 Sep 2026 19:43:33 -0700 To: mm-commits@vger.kernel.org,gourry@gourry.net,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-refactor-find_next_best_node-to-find_next_best_node_in.patch added to mm-unstable branch Message-Id: <20260923024334.2605E1F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: refactor find_next_best_node to find_next_best_node_in has been added to the -mm mm-unstable branch. Its filename is mm-refactor-find_next_best_node-to-find_next_best_node_in.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-refactor-find_next_best_node-to-find_next_best_node_in.patch This patch will later appear in the mm-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 various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Gregory Price Subject: mm: refactor find_next_best_node to find_next_best_node_in Date: Tue, 22 Sep 2026 22:29:01 -0400 Patch series "mm: refactor zonelist constructors and iterators", v3. find_next_best_node() picks the next-closest node when building a fallback list, and hardcodes N_MEMORY as the set it picks from. Refactor it into find_next_best_node_in(), which takes the candidate set explicitly. This makes the existing behaviour explicit at both mm/memory-tiers.c call sites - they select demotion targets in fallback order from N_MEMORY - and lets callers narrow that set. Then extract the per-node construction loop out of build_zonelists() into build_node_zonelist(), parameterised on the candidate nodemask and destination zonelist index. Together these allow a zonelist to be built over a candidate set other than N_MEMORY, into a zonelist other than FALLBACK, and iterated in fallback order over a caller-defined subset. These are prerequisites for generating a private node zonelist (nodes unreachable by default), but are otherwise general improvements to the existing interfaces so I'm proposing them separately. No functional change intended - purely refactor commits. This patch (of 2): find_next_best_node() picks the next-closest node for a fallback list from the full N_MEMORY set. Refactor it into find_next_best_node_in(), which takes an explicit candidates nodemask. This enables building fallback lists with non-N_MEMORY candidates. No functional change: every caller still selects from N_MEMORY. Link: https://lore.kernel.org/20260923022902.2433614-1-gourry@gourry.net Link: https://lore.kernel.org/20260923022902.2433614-2-gourry@gourry.net Signed-off-by: Gregory Price Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka (SUSE) Acked-by: Balbir Singh Reviewed-by: Zi Yan Reviewed-by: Zenghui Yu (Huawei) Cc: David Hildenbrand Cc: Lorenzo Stoakes Cc: Liam R. Howlett Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Joshua Hahn Cc: Rakie Kim Cc: Ying Huang Cc: Brendan Jackman Cc: Johannes Weiner --- mm/internal.h | 6 ++++-- mm/memory-tiers.c | 7 ++++--- mm/page_alloc.c | 13 ++++++++----- 3 files changed, 16 insertions(+), 10 deletions(-) --- a/mm/internal.h~mm-refactor-find_next_best_node-to-find_next_best_node_in +++ a/mm/internal.h @@ -1124,7 +1124,8 @@ extern int node_reclaim_mode; extern unsigned long node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned int order); -extern int find_next_best_node(int node, nodemask_t *used_node_mask); +int find_next_best_node_in(int node, nodemask_t *used_node_mask, + const nodemask_t *candidates); #else #define node_reclaim_mode 0 @@ -1133,7 +1134,8 @@ static inline unsigned long node_reclaim { return 0; } -static inline int find_next_best_node(int node, nodemask_t *used_node_mask) +static inline int find_next_best_node_in(int node, nodemask_t *used_node_mask, + const nodemask_t *candidates) { return NUMA_NO_NODE; } --- a/mm/memory-tiers.c~mm-refactor-find_next_best_node-to-find_next_best_node_in +++ a/mm/memory-tiers.c @@ -370,7 +370,7 @@ int next_demotion_node(int node, const n * closest demotion target. */ nodes_complement(mask, *allowed_mask); - return find_next_best_node(node, &mask); + return find_next_best_node_in(node, &mask, &node_states[N_MEMORY]); } static void disable_all_demotion_targets(void) @@ -450,7 +450,7 @@ static void establish_demotion_targets(v memtier = list_next_entry(memtier, list); tier_nodes = get_memtier_nodemask(memtier); /* - * find_next_best_node, use 'used' nodemask as a skip list. + * find_next_best_node_in, use 'used' nodemask as a skip list. * Add all memory nodes except the selected memory tier * nodelist to skip list so that we find the best node from the * memtier nodelist. @@ -463,7 +463,8 @@ static void establish_demotion_targets(v * in the preferred mask when allocating pages during demotion. */ do { - target = find_next_best_node(node, &tier_nodes); + target = find_next_best_node_in(node, &tier_nodes, + &node_states[N_MEMORY]); if (target == NUMA_NO_NODE) break; --- a/mm/page_alloc.c~mm-refactor-find_next_best_node-to-find_next_best_node_in +++ a/mm/page_alloc.c @@ -5793,9 +5793,10 @@ static int numa_zonelist_order_handler(c static int node_load[MAX_NUMNODES]; /** - * find_next_best_node - find the next node that should appear in a given node's fallback list + * find_next_best_node_in - find the next node that should appear in a given node's fallback list * @node: node whose fallback list we're appending * @used_node_mask: nodemask_t of already used nodes + * @candidates: nodemask_t of nodes eligible for selection * * We use a number of factors to determine which is the next node that should * appear on a given node's fallback list. The node should not have appeared @@ -5807,7 +5808,8 @@ static int node_load[MAX_NUMNODES]; * * Return: node id of the found node or %NUMA_NO_NODE if no node is found. */ -int find_next_best_node(int node, nodemask_t *used_node_mask) +int find_next_best_node_in(int node, nodemask_t *used_node_mask, + const nodemask_t *candidates) { int n, val; int min_val = INT_MAX; @@ -5817,12 +5819,12 @@ int find_next_best_node(int node, nodema * Use the local node if we haven't already, but for memoryless local * node, we should skip it and fall back to other nodes. */ - if (!node_isset(node, *used_node_mask) && node_state(node, N_MEMORY)) { + if (!node_isset(node, *used_node_mask) && node_isset(node, *candidates)) { node_set(node, *used_node_mask); return node; } - for_each_node_state(n, N_MEMORY) { + for_each_node_mask(n, *candidates) { /* Don't want a node to appear more than once */ if (node_isset(n, *used_node_mask)) @@ -5907,7 +5909,8 @@ static void build_zonelists(pg_data_t *p prev_node = local_node; memset(node_order, 0, sizeof(node_order)); - while ((node = find_next_best_node(local_node, &used_mask)) >= 0) { + while ((node = find_next_best_node_in(local_node, &used_mask, + &node_states[N_MEMORY])) >= 0) { /* * We don't want to pressure a particular node. * So adding penalty to the first node in same _ Patches currently in -mm which might be from gourry@gourry.net are mm-mempolicy-take-a-cpuset-cookie-for-the-interleave-node-count.patch mm-mempolicy-use-srcu-for-the-weighted-interleave-state.patch mm-mempolicy-stop-copying-the-nodemask-in-the-interleave-paths.patch mm-huge_memory-skip-zone-device-folios-in-madvise_free_huge_pmd.patch mm-madvise-skip-zone-device-folios-in-cold-pageout-pmd-range.patch mm-mempolicy-skip-zone-device-folios-when-queueing-folios.patch mm-memory_hotplug-factor-out-node_is_memoryless.patch mm-mempolicy-use-vm_normal_folio_pmd-in-queue_folios_pmd.patch mm-madvise-use-vm_normal_folio_pmd-in-cold-pageout-pmd-range.patch mm-refactor-find_next_best_node-to-find_next_best_node_in.patch mm-page_alloc-refactor-build_node_zonelist-out-of-build_zonelists.patch proc-task_mmu-handle-special-pmds-in-clear_refs-and-pagemap.patch mm-madvise-reclaim-isolated-folios-if-pte-restart-fails.patch mm-madvise-use-folio_trylock-in-the-cold-pageout-pmd-split.patch