| Message ID | 20240112154621.261852-1-frederic@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | rcu: Fix expedited GP deadlock | expand |
On Fri, Jan 12, 2024 at 04:46:14PM +0100, Frederic Weisbecker wrote: > TREE04 can trigger a writer stall if run with memory pressure. This > is due to a circular dependency between waiting for expedited grace > period and polling on expedited grace period when workqueues go back > to mayday serialization. > > Here is a proposal fix. > > Changes since v2 (no functional changes, just renames and reorganization): > > _ Move nocb cleanups to their own series > _ Rename can_queue parameter to use_worker [2/7] > _ Better explain the rename of the mutex [3/7] > _ New commit with just code move to ease review [4/7] > _ Comment declaration of the new rnp->exp_worker field [5/7] > > Thanks. Hearing no objections, queued for testing and further review, thank you! Thanx, Paul > Frederic Weisbecker (7): > rcu/exp: Fix RCU expedited parallel grace period kworker allocation > failure recovery > rcu/exp: Handle RCU expedited grace period kworker allocation failure > rcu: s/boost_kthread_mutex/kthread_mutex > rcu/exp: Move expedited kthread worker creation functions above > rcutree_prepare_cpu() > rcu/exp: Make parallel exp gp kworker per rcu node > rcu/exp: Handle parallel exp gp kworkers affinity > rcu/exp: Remove rcu_par_gp_wq > > kernel/rcu/rcu.h | 5 -- > kernel/rcu/tree.c | 175 +++++++++++++++++++++++++++------------ > kernel/rcu/tree.h | 11 ++- > kernel/rcu/tree_exp.h | 78 +++-------------- > kernel/rcu/tree_plugin.h | 52 ++---------- > 5 files changed, 142 insertions(+), 179 deletions(-) > > -- > 2.34.1 > >
TREE04 can trigger a writer stall if run with memory pressure. This is due to a circular dependency between waiting for expedited grace period and polling on expedited grace period when workqueues go back to mayday serialization. Here is a proposal fix. Changes since v2 (no functional changes, just renames and reorganization): _ Move nocb cleanups to their own series _ Rename can_queue parameter to use_worker [2/7] _ Better explain the rename of the mutex [3/7] _ New commit with just code move to ease review [4/7] _ Comment declaration of the new rnp->exp_worker field [5/7] Thanks. Frederic Weisbecker (7): rcu/exp: Fix RCU expedited parallel grace period kworker allocation failure recovery rcu/exp: Handle RCU expedited grace period kworker allocation failure rcu: s/boost_kthread_mutex/kthread_mutex rcu/exp: Move expedited kthread worker creation functions above rcutree_prepare_cpu() rcu/exp: Make parallel exp gp kworker per rcu node rcu/exp: Handle parallel exp gp kworkers affinity rcu/exp: Remove rcu_par_gp_wq kernel/rcu/rcu.h | 5 -- kernel/rcu/tree.c | 175 +++++++++++++++++++++++++++------------ kernel/rcu/tree.h | 11 ++- kernel/rcu/tree_exp.h | 78 +++-------------- kernel/rcu/tree_plugin.h | 52 ++---------- 5 files changed, 142 insertions(+), 179 deletions(-)