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b=elOH0invuuhKBmLJyo17T5vPdD4BWx9gY9GIpEETdazFh9fzbL6NrkxFMRy7qTq84 W+GFuduX9Z+YzonDV4Q13BqBo9uGm/SP4HP7cHeILofrqI8+/Nt4BmKIDgqJ4uoeSa zKFhJPjqyjaWYv4A1kW1LfxWPPxeIGfC1MMfnRuWH2mdjLOP33I4LYheS3RDUFak5Q lmnWyr9TRHt2rPOdX4FN+I0C85jXLdCbkDN5DHM56xG5Pb8GzhH/CsqRoHrnNBK6vZ xP5CaJt8mc15KxeYxUVCVonHJO/pwZLfXkq/DI1WUET7WhG5n/zcApe/6PB39CG8sL 1cw1gj0CSMDYA== Message-ID: <7e247c67-ea51-4c2e-b02d-8e5ed31cc5e6@kernel.org> Date: Mon, 14 Sep 2026 16:56:30 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 2/2] mm/page_alloc: refactor build_node_zonelist() out of build_zonelists() Content-Language: en-US To: Gregory Price , linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, brendan.jackman@linux.dev, hannes@cmpxchg.org, ziy@nvidia.com References: <20260912030424.2889731-1-gourry@gourry.net> <20260912030424.2889731-3-gourry@gourry.net> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: C843D8000C X-Stat-Signature: 4397d84nk9bpsjgauc3gdmyh7a3a6uip X-Rspam-User: X-HE-Tag: 1789397795-44853 X-HE-Meta: U2FsdGVkX197jRWzRoj+t7gEn5U2Kvrbu25sDgAIl/+URrXoAagm8ce4yxDlHGiQjSFzg5oYDO2ugK9rAixAjuqShCky7R1t6gMl+NfzQL0+swT57ZFs8VKR2hBWXDvAzMPggVrnIhpi/VhgsDk0wC3Q1o3qMy0tExSKbZrj+ucYLZmW90x3SphMeZ73N98vTL8w3vqp74Qy+/lr6JRX5eGCEq7pAI9jfpQgdblEoOn8HM59X96sqEnIFP1SAsj0WsDHEIo7PBaBd2k3LTpGJrctciXSymDo6Kau3C/CXafi2ARageBxuRZ2D9zHxunLsQw1wAav/bXV0tMV63Z20NFkJ89C7FoszjiUfMaQemRfncM2KM9h3Jo2CRCZFMIw50qr6TqgZpz10qPOQxlaoSlI8vE8mD63CLG1TsYjUT1dXCBLpBw0mbGESAYMFP4Mi9DFa93TOmEYQEUr0/OmMqol82DBxSANR0F8+DHvsTPQuJJnDFvPg15WDO8LjS5UeVvyW/jpjDyo1JiQaCefdYVUMomNQmFn0mBVQQ6hwbk49eA1/H0MoDHrH5yw+ApLZtpBt/OwR0yeFCRea7SbMru1uncXr+U91/jN5CuFxdbtOpwtLUIKDMMLe+XfRD+HIWmeTEpDpgK1OKrUOP5v/VlhJXxQ9n1HyXoyHl91u1KOBnRlRwjxQug2iUdCnt38vN3KnKrKRw6NywdRyNKkAwgyo2tYo+7QV80GAC60kZscxby9O0vk6UbvDWe0od+9OalJ8BHc3aHPw8zNvMljg6FXohEgDVzhEg/cpPoWQWovtsRk8xNLfesnRFX3jRLIl1PIWNIfifqSHOJshmizTPghxOT+7v8aqf9g1TExeJrRohikQt1KA5LgZnMKnBm8vl1Qco4Qu5L+Hs5HIiEHVQInPvutd6rVrilRVW1IN/FmyNtUZBQJWHIpFjTW5s1vUjCp8m5RGPEahk6bOy+ HsK4nIj0 ZTv8ezgEPW4+8fmhwmPi/ieuzQWiwKUEh6muDXpg4tth1KxlidaRURGoW/i0eEOoaD949aWyhsHK8l7tBgy7hhm57uewno7azf1DL8nc/Ig5O/01YmO+/rvS6vyY0zeYV3IfrFez2Nx+1/RDvkpNn43Hhp4aSSovLpzbxUchskoulqwmcILUN5crgBJ0AsraGdoE4oc98sxAVHFt2FHK92znDF3ixLKIOilxxIEznXzB8nGxOxxMfnvqVTAkq5XKNFR3MU+82+lcJzvqWVfXvyTo9D1TLUZ8svx8MIGsWyYP/3GY5zwFr/UR/cKnmxrBxrW+H+GlwJY1fS2CXV1E4xzNat71HPt5JExUvIarzRxs8n+CneWBwranqixFey/KzeE86GjQpCYuR0kk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/12/26 05:04, Gregory Price wrote: > Extract per-node fallback-list construction into build_node_zonelist(). > Build each selected node directly into the destination zonelist so no > intermediate node_order array or node count is needed. Print the fallback > order as each node is added. > > This lets us build new zonelists from candidate nodemasks instead of just > the default N_MEMORY node state list. > > No functional change: build_zonelists() builds and prints the same FALLBACK > list over N_MEMORY with node_load updates as before. > > Signed-off-by: Gregory Price Nice, glad this way of refactor was feasible. Reviewed-by: Vlastimil Babka (SUSE) > --- > mm/page_alloc.c | 63 ++++++++++++++++++------------------------------- > 1 file changed, 23 insertions(+), 40 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 7efce139d562..d1888d5630e0 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5857,31 +5857,6 @@ int find_next_best_node_in(int node, nodemask_t *used_node_mask, > } > > > -/* > - * Build zonelists ordered by node and zones within node. > - * This results in maximum locality--normal zone overflows into local > - * DMA zone, if any--but risks exhausting DMA zone. > - */ > -static void build_zonelists_in_node_order(pg_data_t *pgdat, int *node_order, > - unsigned nr_nodes) > -{ > - struct zoneref *zonerefs; > - int i; > - > - zonerefs = pgdat->node_zonelists[ZONELIST_FALLBACK]._zonerefs; > - > - for (i = 0; i < nr_nodes; i++) { > - int nr_zones; > - > - pg_data_t *node = NODE_DATA(node_order[i]); > - > - nr_zones = build_zonerefs_node(node, zonerefs); > - zonerefs += nr_zones; > - } > - zonerefs->zone = NULL; > - zonerefs->zone_idx = 0; > -} > - > /* > * Build __GFP_THISNODE zonelists > */ > @@ -5897,20 +5872,24 @@ static void build_thisnode_zonelists(pg_data_t *pgdat) > zonerefs->zone_idx = 0; > } > > -static void build_zonelists(pg_data_t *pgdat) > +/* > + * Build one zonelist ordered by node and zones within node. This results in > + * maximum locality--normal zone overflows into local DMA zone, if any--but > + * risks exhausting DMA zone. > + */ > +static void build_node_zonelist(pg_data_t *pgdat, const nodemask_t *candidates, > + int zlidx) > { > - static int node_order[MAX_NUMNODES]; > - int node, nr_nodes = 0; > + struct zoneref *zonerefs = pgdat->node_zonelists[zlidx]._zonerefs; > nodemask_t used_mask = NODE_MASK_NONE; > - int local_node, prev_node; > + int local_node = pgdat->node_id; > + int prev_node = local_node; > + int node; > > - /* NUMA-aware ordering of nodes */ > - local_node = pgdat->node_id; > - prev_node = local_node; > + pr_info("Fallback order for Node %d: ", local_node); > > - memset(node_order, 0, sizeof(node_order)); > while ((node = find_next_best_node_in(local_node, &used_mask, > - &node_states[N_MEMORY])) >= 0) { > + candidates)) >= 0) { > /* > * We don't want to pressure a particular node. > * So adding penalty to the first node in same > @@ -5920,18 +5899,22 @@ static void build_zonelists(pg_data_t *pgdat) > node_distance(local_node, prev_node)) > node_load[node] += 1; > > - node_order[nr_nodes++] = node; > + zonerefs += build_zonerefs_node(NODE_DATA(node), zonerefs); > + pr_cont("%d ", node); > prev_node = node; > } > > - build_zonelists_in_node_order(pgdat, node_order, nr_nodes); > - build_thisnode_zonelists(pgdat); > - pr_info("Fallback order for Node %d: ", local_node); > - for (node = 0; node < nr_nodes; node++) > - pr_cont("%d ", node_order[node]); > + zonerefs->zone = NULL; > + zonerefs->zone_idx = 0; > pr_cont("\n"); > } > > +static void build_zonelists(pg_data_t *pgdat) > +{ > + build_node_zonelist(pgdat, &node_states[N_MEMORY], ZONELIST_FALLBACK); > + build_thisnode_zonelists(pgdat); > +} > + > #ifdef CONFIG_HAVE_MEMORYLESS_NODES > /* > * Return node id of node used for "local" allocations.