From 9f5d5aef3072a33c6f9bfb954bb0cba1c2541849 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 3 Apr 2024 16:29:14 +0200 Subject: Revert "workqueue: Implement system-wide nr_active enforcement for unbound workqueues" This reverts commit 843288afd3cc6f3342659c6cf81fc47684d25563 which is commit 5797b1c18919cd9c289ded7954383e499f729ce0 upstream. The workqueue patches backported to 6.8.y caused some reported regressions, so revert them for now. Reported-by: Thorsten Leemhuis Cc: Tejun Heo Cc: Marek Szyprowski Cc: Nathan Chancellor Cc: Sasha Levin Cc: Audra Mitchell Link: https://lore.kernel.org/all/ce4c2f67-c298-48a0-87a3-f933d646c73b@leemhuis.info/ Signed-off-by: Greg Kroah-Hartman --- include/linux/workqueue.h | 35 +++-------------------------------- 1 file changed, 3 insertions(+), 32 deletions(-) (limited to 'include') diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 515e7958c6c1..2cc0a9606175 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -391,13 +391,6 @@ enum { WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */ WQ_UNBOUND_MAX_ACTIVE = WQ_MAX_ACTIVE, WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2, - - /* - * Per-node default cap on min_active. Unless explicitly set, min_active - * is set to min(max_active, WQ_DFL_MIN_ACTIVE). For more details, see - * workqueue_struct->min_active definition. - */ - WQ_DFL_MIN_ACTIVE = 8, }; /* @@ -440,33 +433,11 @@ extern struct workqueue_struct *system_freezable_power_efficient_wq; * alloc_workqueue - allocate a workqueue * @fmt: printf format for the name of the workqueue * @flags: WQ_* flags - * @max_active: max in-flight work items, 0 for default + * @max_active: max in-flight work items per CPU, 0 for default * remaining args: args for @fmt * - * For a per-cpu workqueue, @max_active limits the number of in-flight work - * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be - * executing at most one work item for the workqueue. - * - * For unbound workqueues, @max_active limits the number of in-flight work items - * for the whole system. e.g. @max_active of 16 indicates that that there can be - * at most 16 work items executing for the workqueue in the whole system. - * - * As sharing the same active counter for an unbound workqueue across multiple - * NUMA nodes can be expensive, @max_active is distributed to each NUMA node - * according to the proportion of the number of online CPUs and enforced - * independently. - * - * Depending on online CPU distribution, a node may end up with per-node - * max_active which is significantly lower than @max_active, which can lead to - * deadlocks if the per-node concurrency limit is lower than the maximum number - * of interdependent work items for the workqueue. - * - * To guarantee forward progress regardless of online CPU distribution, the - * concurrency limit on every node is guaranteed to be equal to or greater than - * min_active which is set to min(@max_active, %WQ_DFL_MIN_ACTIVE). This means - * that the sum of per-node max_active's may be larger than @max_active. - * - * For detailed information on %WQ_* flags, please refer to + * Allocate a workqueue with the specified parameters. For detailed + * information on WQ_* flags, please refer to * Documentation/core-api/workqueue.rst. * * RETURNS: -- cgit v1.2.3