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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-06-09 04:52:54 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-06-09 04:52:54 +0300 |
commit | 9cd6357f100b3eb0f5027b1ff1a5eebb9f785145 (patch) | |
tree | a09d8c6a7f52edae589990f27ef07071bfa92e9a | |
parent | 8d15d5e1851b1bbb9cd3289b84c7f32399e06ac5 (diff) | |
parent | 5647e53f7856bb39dae781fe26aa65a699e2fc9f (diff) | |
download | linux-9cd6357f100b3eb0f5027b1ff1a5eebb9f785145.tar.xz |
Merge tag 'cgroup-for-6.4-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- Fix css_set reference leaks on fork failures
- Fix CPU hotplug locking in cgroup_transfer_tasks() which is used by
cgroup1 cpuset
- Doc update
* tag 'cgroup-for-6.4-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: Documentation: Clarify usage of memory limits
cgroup: always put cset in cgroup_css_set_put_fork
cgroup: fix missing cpus_read_{lock,unlock}() in cgroup_transfer_tasks()
-rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 22 | ||||
-rw-r--r-- | kernel/cgroup/cgroup-v1.c | 4 | ||||
-rw-r--r-- | kernel/cgroup/cgroup.c | 17 |
3 files changed, 20 insertions, 23 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index f67c0829350b..e592a9364473 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1213,23 +1213,25 @@ PAGE_SIZE multiple when read back. A read-write single value file which exists on non-root cgroups. The default is "max". - Memory usage throttle limit. This is the main mechanism to - control memory usage of a cgroup. If a cgroup's usage goes + Memory usage throttle limit. If a cgroup's usage goes over the high boundary, the processes of the cgroup are throttled and put under heavy reclaim pressure. Going over the high limit never invokes the OOM killer and - under extreme conditions the limit may be breached. + under extreme conditions the limit may be breached. The high + limit should be used in scenarios where an external process + monitors the limited cgroup to alleviate heavy reclaim + pressure. memory.max A read-write single value file which exists on non-root cgroups. The default is "max". - Memory usage hard limit. This is the final protection - mechanism. If a cgroup's memory usage reaches this limit and - can't be reduced, the OOM killer is invoked in the cgroup. - Under certain circumstances, the usage may go over the limit - temporarily. + Memory usage hard limit. This is the main mechanism to limit + memory usage of a cgroup. If a cgroup's memory usage reaches + this limit and can't be reduced, the OOM killer is invoked in + the cgroup. Under certain circumstances, the usage may go + over the limit temporarily. In default configuration regular 0-order allocations always succeed unless OOM killer chooses current task as a victim. @@ -1238,10 +1240,6 @@ PAGE_SIZE multiple when read back. Caller could retry them differently, return into userspace as -ENOMEM or silently ignore in cases like disk readahead. - This is the ultimate protection mechanism. As long as the - high limit is used and monitored properly, this limit's - utility is limited to providing the final safety net. - memory.reclaim A write-only nested-keyed file which exists for all cgroups. diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c index aeef06c465ef..5407241dbb45 100644 --- a/kernel/cgroup/cgroup-v1.c +++ b/kernel/cgroup/cgroup-v1.c @@ -108,7 +108,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) cgroup_lock(); - percpu_down_write(&cgroup_threadgroup_rwsem); + cgroup_attach_lock(true); /* all tasks in @from are being moved, all csets are source */ spin_lock_irq(&css_set_lock); @@ -144,7 +144,7 @@ int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) } while (task && !ret); out_err: cgroup_migrate_finish(&mgctx); - percpu_up_write(&cgroup_threadgroup_rwsem); + cgroup_attach_unlock(true); cgroup_unlock(); return ret; } diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 625d7483951c..245cf62ce85a 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6486,19 +6486,18 @@ err: static void cgroup_css_set_put_fork(struct kernel_clone_args *kargs) __releases(&cgroup_threadgroup_rwsem) __releases(&cgroup_mutex) { + struct cgroup *cgrp = kargs->cgrp; + struct css_set *cset = kargs->cset; + cgroup_threadgroup_change_end(current); - if (kargs->flags & CLONE_INTO_CGROUP) { - struct cgroup *cgrp = kargs->cgrp; - struct css_set *cset = kargs->cset; + if (cset) { + put_css_set(cset); + kargs->cset = NULL; + } + if (kargs->flags & CLONE_INTO_CGROUP) { cgroup_unlock(); - - if (cset) { - put_css_set(cset); - kargs->cset = NULL; - } - if (cgrp) { cgroup_put(cgrp); kargs->cgrp = NULL; |