BMC/Intel-BMC/linux.git/block/bfq-cgroup.c, branch dev-5.4

block, bfq: invoke flush_idle_tree after reparent_active_queues in pd_offline

2020-04-23T08:36:26+00:00

commit 4d38a87fbb77fb9ff2ff4e914162a8ae6453eff5 upstream. In bfq_pd_offline(), the function bfq_flush_idle_tree() is invoked to flush the rb tree that contains all idle entities belonging to the pd (cgroup) being destroyed. In particular, bfq_flush_idle_tree() is invoked before bfq_reparent_active_queues(). Yet the latter may happen to add some entities to the idle tree. It happens if, in some of the calls to bfq_bfqq_move() performed by bfq_reparent_active_queues(), the queue to move is empty and gets expired. This commit simply reverses the invocation order between bfq_flush_idle_tree() and bfq_reparent_active_queues(). Tested-by: cki-project@redhat.com Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block, bfq: make reparent_leaf_entity actually work only on leaf entities

2020-04-23T08:36:26+00:00

commit 576682fa52cbd95deb3773449566274f206acc58 upstream. bfq_reparent_leaf_entity() reparents the input leaf entity (a leaf entity represents just a bfq_queue in an entity tree). Yet, the input entity is guaranteed to always be a leaf entity only in two-level entity trees. In this respect, because of the error fixed by commit 14afc5936197 ("block, bfq: fix overwrite of bfq_group pointer in bfq_find_set_group()"), all (wrongly collapsed) entity trees happened to actually have only two levels. After the latter commit, this does not hold any longer. This commit fixes this problem by modifying bfq_reparent_leaf_entity(), so that it searches an active leaf entity down the path that stems from the input entity. Such a leaf entity is guaranteed to exist when bfq_reparent_leaf_entity() is invoked. Tested-by: cki-project@redhat.com Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block, bfq: turn put_queue into release_process_ref in __bfq_bic_change_cgroup

2020-04-23T08:36:26+00:00

commit c8997736650060594845e42c5d01d3118aec8d25 upstream. A bfq_put_queue() may be invoked in __bfq_bic_change_cgroup(). The goal of this put is to release a process reference to a bfq_queue. But process-reference releases may trigger also some extra operation, and, to this goal, are handled through bfq_release_process_ref(). So, turn the invocation of bfq_put_queue() into an invocation of bfq_release_process_ref(). Tested-by: cki-project@redhat.com Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block, bfq: move forward the getting of an extra ref in bfq_bfqq_move

2020-04-17T08:50:02+00:00

[ Upstream commit fd1bb3ae54a9a2e0c42709de861c69aa146b8955 ] Commit ecedd3d7e199 ("block, bfq: get extra ref to prevent a queue from being freed during a group move") gets an extra reference to a bfq_queue before possibly deactivating it (temporarily), in bfq_bfqq_move(). This prevents the bfq_queue from disappearing before being reactivated in its new group. Yet, the bfq_queue may also be expired (i.e., its service may be stopped) before the bfq_queue is deactivated. And also an expiration may lead to a premature freeing. This commit fixes this issue by simply moving forward the getting of the extra reference already introduced by commit ecedd3d7e199 ("block, bfq: get extra ref to prevent a queue from being freed during a group move"). Reported-by: cki-project@redhat.com Tested-by: cki-project@redhat.com Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block, bfq: fix overwrite of bfq_group pointer in bfq_find_set_group()

2020-03-25T07:25:49+00:00

[ Upstream commit 14afc59361976c0ba39e3a9589c3eaa43ebc7e1d ] The bfq_find_set_group() function takes as input a blkcg (which represents a cgroup) and retrieves the corresponding bfq_group, then it updates the bfq internal group hierarchy (see comments inside the function for why this is needed) and finally it returns the bfq_group. In the hierarchy update cycle, the pointer holding the correct bfq_group that has to be returned is mistakenly used to traverse the hierarchy bottom to top, meaning that in each iteration it gets overwritten with the parent of the current group. Since the update cycle stops at root's children (depth = 2), the overwrite becomes a problem only if the blkcg describes a cgroup at a hierarchy level deeper than that (depth > 2). In this case the root's child that happens to be also an ancestor of the correct bfq_group is returned. The main consequence is that processes contained in a cgroup at depth greater than 2 are wrongly placed in the group described above by BFQ. This commits fixes this problem by using a different bfq_group pointer in the update cycle in order to avoid the overwrite of the variable holding the original group reference. Reported-by: Kwon Je Oh Signed-off-by: Carlo Nonato Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block, bfq: remove ifdefs from around gets/puts of bfq groups

2020-03-12T12:00:32+00:00

commit 4d8340d0d4d90e7ca367d18ec16c2fefa89a339c upstream. ifdefs around gets and puts of bfq groups reduce readability, remove them. Tested-by: Oleksandr Natalenko Reported-by: Jens Axboe Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block, bfq: get a ref to a group when adding it to a service tree

2020-03-12T12:00:32+00:00

commit db37a34c563bf4692b36990ae89005c031385e52 upstream. BFQ schedules generic entities, which may represent either bfq_queues or groups of bfq_queues. When an entity is inserted into a service tree, a reference must be taken, to make sure that the entity does not disappear while still referred in the tree. Unfortunately, such a reference is mistakenly taken only if the entity represents a bfq_queue. This commit takes a reference also in case the entity represents a group. Tested-by: Oleksandr Natalenko Tested-by: Chris Evich Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block, bfq: get extra ref to prevent a queue from being freed during a group move

2020-03-12T12:00:08+00:00

[ Upstream commit ecedd3d7e19911ab8fe42f17b77c0a30fe7f4db3 ] In bfq_bfqq_move(), the bfq_queue, say Q, to be moved to a new group may happen to be deactivated in the scheduling data structures of the source group (and then activated in the destination group). If Q is referred only by the data structures in the source group when the deactivation happens, then Q is freed upon the deactivation. This commit addresses this issue by getting an extra reference before the possible deactivation, and releasing this extra reference after Q has been moved. Tested-by: Chris Evich Tested-by: Oleksandr Natalenko Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

bfq: Add per-device weight

2019-09-06T20:33:52+00:00

This adds to BFQ the missing per-device weight interfaces: blkio.bfq.weight_device on legacy and io.bfq.weight on unified. The implementation pretty closely resembles what we had in CFQ and the parsing code is basically reused. Tests ===== Using two cgroups and three block devices, having weights setup as: Cgroup test1 test2 ============================================ default 100 500 sda 500 100 sdb default default sdc 200 200 cgroup v1 runs -------------- sda.test1.out: READ: bw=913MiB/s sda.test2.out: READ: bw=183MiB/s sdb.test1.out: READ: bw=213MiB/s sdb.test2.out: READ: bw=1054MiB/s sdc.test1.out: READ: bw=650MiB/s sdc.test2.out: READ: bw=650MiB/s cgroup v2 runs -------------- sda.test1.out: READ: bw=915MiB/s sda.test2.out: READ: bw=184MiB/s sdb.test1.out: READ: bw=216MiB/s sdb.test2.out: READ: bw=1069MiB/s sdc.test1.out: READ: bw=621MiB/s sdc.test2.out: READ: bw=622MiB/s Signed-off-by: Fam Zheng Acked-by: Tejun Heo Reviewed-by: Paolo Valente Signed-off-by: Jens Axboe

bfq: Extract bfq_group_set_weight from bfq_io_set_weight_legacy

2019-09-06T20:33:50+00:00

This function will be useful when we update weight from the soon-coming per-device interface. Signed-off-by: Fam Zheng Reviewed-by: Paolo Valente Signed-off-by: Jens Axboe