[PATCH 23/29] mm: shrinker: add refcount and completion_wait fields
From: Qi Zheng <hidden>
Date: 2023-06-22 09:04:31
Also in:
dm-devel, dri-devel, intel-gfx, linux-arm-msm, linux-bcache, linux-btrfs, linux-ext4, linux-fsdevel, linux-mm, linux-nfs, linux-xfs, lkml
Subsystem:
memory management, memory management - mglru (multi-gen lru), memory management - reclaim, shrinker, the rest · Maintainers:
Andrew Morton, Johannes Weiner, Dave Chinner, Linus Torvalds
This commit introduces refcount and completion_wait fields to struct shrinker to manage the life cycle of shrinker instance. Just a preparation work for implementing the lockless slab shrink, no functional changes. Signed-off-by: Qi Zheng <redacted> --- include/linux/shrinker.h | 11 +++++++++++ mm/vmscan.c | 5 +++++ 2 files changed, 16 insertions(+)
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
index 4094e4c44e80..7bfeb2f25246 100644
--- a/include/linux/shrinker.h
+++ b/include/linux/shrinker.h@@ -4,6 +4,8 @@ #include <linux/atomic.h> #include <linux/types.h> +#include <linux/refcount.h> +#include <linux/completion.h> /* * This struct is used to pass information from page reclaim to the shrinkers.
@@ -70,6 +72,9 @@ struct shrinker { int seeks; /* seeks to recreate an obj */ unsigned flags; + refcount_t refcount; + struct completion completion_wait; + void *private_data; /* These are for internal use */
@@ -118,6 +123,12 @@ struct shrinker *shrinker_alloc_and_init(count_objects_cb count, void shrinker_free(struct shrinker *shrinker); void unregister_and_free_shrinker(struct shrinker *shrinker); +static inline void shrinker_put(struct shrinker *shrinker) +{ + if (refcount_dec_and_test(&shrinker->refcount)) + complete(&shrinker->completion_wait); +} + #ifdef CONFIG_SHRINKER_DEBUG extern int shrinker_debugfs_add(struct shrinker *shrinker); extern struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker,
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 3a8d50ad6ff6..6f9c4750effa 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c@@ -740,6 +740,8 @@ void free_prealloced_shrinker(struct shrinker *shrinker) void register_shrinker_prepared(struct shrinker *shrinker) { down_write(&shrinker_rwsem); + refcount_set(&shrinker->refcount, 1); + init_completion(&shrinker->completion_wait); list_add_tail(&shrinker->list, &shrinker_list); shrinker->flags |= SHRINKER_REGISTERED; shrinker_debugfs_add(shrinker);
@@ -794,6 +796,9 @@ void unregister_shrinker(struct shrinker *shrinker) if (!(shrinker->flags & SHRINKER_REGISTERED)) return; + shrinker_put(shrinker); + wait_for_completion(&shrinker->completion_wait); + down_write(&shrinker_rwsem); list_del(&shrinker->list); shrinker->flags &= ~SHRINKER_REGISTERED;
--
2.30.2