Linux-stable-mirror September 2025

linux-stable-mirror@lists.linaro.org

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2 discussions

[PATCH] coresight: trbe: Fix incorrect error check for devm_kzalloc

by Miaoqian Lin

Fix incorrect use of IS_ERR() to check devm_kzalloc() return value. devm_kzalloc() returns NULL on failure, not an error pointer. This issue was introduced by commit 4277f035d227 ("coresight: trbe: Add a representative coresight_platform_data for TRBE") which replaced the original function but didn't update the error check. Fixes: 4277f035d227 ("coresight: trbe: Add a representative coresight_platform_data for TRBE") Cc: stable(a)vger.kernel.org Signed-off-by: Miaoqian Lin <linmq006(a)gmail.com> --- drivers/hwtracing/coresight/coresight-trbe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c index 8267dd1a2130..caf873adfc3a 100644 --- a/drivers/hwtracing/coresight/coresight-trbe.c +++ b/drivers/hwtracing/coresight/coresight-trbe.c @@ -1279,7 +1279,7 @@ static void arm_trbe_register_coresight_cpu(struct trbe_drvdata *drvdata, int cp * into the device for that purpose. */ desc.pdata = devm_kzalloc(dev, sizeof(*desc.pdata), GFP_KERNEL); - if (IS_ERR(desc.pdata)) + if (!desc.pdata) goto cpu_clear; desc.type = CORESIGHT_DEV_TYPE_SINK; -- 2.35.1

25 minutes

[PATCH v2] mm: memory-tiering: fix PGPROMOTE_CANDIDATE counting

by Ruan Shiyang

Goto-san reported confusing pgpromote statistics where the pgpromote_success count significantly exceeded pgpromote_candidate. On a system with three nodes (nodes 0-1: DRAM 4GB, node 2: NVDIMM 4GB): # Enable demotion only echo 1 > /sys/kernel/mm/numa/demotion_enabled numactl -m 0-1 memhog -r200 3500M >/dev/null & pid=$! sleep 2 numactl memhog -r100 2500M >/dev/null & sleep 10 kill -9 $pid # terminate the 1st memhog # Enable promotion echo 2 > /proc/sys/kernel/numa_balancing After a few seconds, we observeed `pgpromote_candidate < pgpromote_success` $ grep -e pgpromote /proc/vmstat pgpromote_success 2579 pgpromote_candidate 0 In this scenario, after terminating the first memhog, the conditions for pgdat_free_space_enough() are quickly met, and triggers promotion. However, these migrated pages are only counted for in PGPROMOTE_SUCCESS, not in PGPROMOTE_CANDIDATE. To solve these confusing statistics, introduce PGPROMOTE_CANDIDATE_NRL to count the missed promotion pages. And also, not counting these pages into PGPROMOTE_CANDIDATE is to avoid changing the existing algorithm or performance of the promotion rate limit. Link: https://lkml.kernel.org/r/20250729035101.1601407-1-ruansy.fnst@fujitsu.com Co-developed-by: Li Zhijian <lizhijian(a)fujitsu.com> Signed-off-by: Ruan Shiyang <ruansy.fnst(a)fujitsu.com> Reported-by: Yasunori Gotou (Fujitsu) <y-goto(a)fujitsu.com> Suggested-by: Huang Ying <ying.huang(a)linux.alibaba.com> Acked-by: Vlastimil Babka <vbabka(a)suse.cz> Cc: Ingo Molnar <mingo(a)redhat.com> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Juri Lelli <juri.lelli(a)redhat.com> Cc: Vincent Guittot <vincent.guittot(a)linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann(a)arm.com> Cc: Steven Rostedt <rostedt(a)goodmis.org> Cc: Ben Segall <bsegall(a)google.com> Cc: Mel Gorman <mgorman(a)suse.de> Cc: Valentin Schneider <vschneid(a)redhat.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- Changes since v1: 1. change Li Zhijian from 'Signed-off-by' to 'Co-developed-by' per Vlastimil. 2. add Acked-by: Vlastimil Babka <vbabka(a)suse.cz> --- include/linux/mmzone.h | 16 +++++++++++++++- kernel/sched/fair.c | 5 +++-- mm/vmstat.c | 1 + 3 files changed, 19 insertions(+), 3 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 0c5da9141983..9d3ea9085556 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -234,7 +234,21 @@ enum node_stat_item { #endif #ifdef CONFIG_NUMA_BALANCING PGPROMOTE_SUCCESS, /* promote successfully */ - PGPROMOTE_CANDIDATE, /* candidate pages to promote */ + /** + * Candidate pages for promotion based on hint fault latency. This + * counter is used to control the promotion rate and adjust the hot + * threshold. + */ + PGPROMOTE_CANDIDATE, + /** + * Not rate-limited (NRL) candidate pages for those can be promoted + * without considering hot threshold because of enough free pages in + * fast-tier node. These promotions bypass the regular hotness checks + * and do NOT influence the promotion rate-limiter or + * threshold-adjustment logic. + * This is for statistics/monitoring purposes. + */ + PGPROMOTE_CANDIDATE_NRL, #endif /* PGDEMOTE_*: pages demoted */ PGDEMOTE_KSWAPD, diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index b173a059315c..82c8d804c54c 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1923,11 +1923,13 @@ bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, struct pglist_data *pgdat; unsigned long rate_limit; unsigned int latency, th, def_th; + long nr = folio_nr_pages(folio); pgdat = NODE_DATA(dst_nid); if (pgdat_free_space_enough(pgdat)) { /* workload changed, reset hot threshold */ pgdat->nbp_threshold = 0; + mod_node_page_state(pgdat, PGPROMOTE_CANDIDATE_NRL, nr); return true; } @@ -1941,8 +1943,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct folio *folio, if (latency >= th) return false; - return !numa_promotion_rate_limit(pgdat, rate_limit, - folio_nr_pages(folio)); + return !numa_promotion_rate_limit(pgdat, rate_limit, nr); } this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid); diff --git a/mm/vmstat.c b/mm/vmstat.c index 71cd1ceba191..e74f0b2a1021 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1280,6 +1280,7 @@ const char * const vmstat_text[] = { #ifdef CONFIG_NUMA_BALANCING [I(PGPROMOTE_SUCCESS)] = "pgpromote_success", [I(PGPROMOTE_CANDIDATE)] = "pgpromote_candidate", + [I(PGPROMOTE_CANDIDATE_NRL)] = "pgpromote_candidate_nrl", #endif [I(PGDEMOTE_KSWAPD)] = "pgdemote_kswapd", [I(PGDEMOTE_DIRECT)] = "pgdemote_direct", -- 2.43.0

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Linux-stable-mirror September 2025