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memobj: transform memobj lock to refcounting

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We had a deadlock between:
 - free_process_memory_range (take lock) -> ihk_mc_pt_free_range ->
... -> remote_flush_tlb_array_cpumask -> "/* Wait for all cores */"
and
 - obj_list_lookup() under fileobj_list_lock that disabled irqs
and thus never ack'd the remote flush

The rework is quite big but removes the need for the big lock,
although devobj and shmobj needed a new smaller lock to be
introduced - the new locks are used much more locally and
should not cause problems.

On the bright side, refcounting being moved to memobj level means
we could remove refcounting implemented separately in all object
types and simplifies code a bit.

Change-Id: I6bc8438a98b1d8edddc91c4ac33c11b88e097ebb
This commit is contained in:
Dominique Martinet
2018-08-07 15:40:25 +09:00
parent b51886421e
commit c25fb2aa39
10 changed files with 307 additions and 403 deletions
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2
kernel/include/shm.h
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@ -57,6 +57,7 @@ struct shmobj {
struct shmlock_user * user;
struct shmid_ds ds;
struct list_head page_list;
ihk_spinlock_t page_list_lock;
struct list_head chain; /* shmobj_list */
};
@ -104,7 +105,6 @@ static inline void shmlock_users_unlock(void)
void shmobj_list_lock(void);
void shmobj_list_unlock(void);
int shmobj_create_indexed(struct shmid_ds *ds, struct shmobj **objp);
void shmobj_destroy(struct shmobj *obj);
void shmlock_user_free(struct shmlock_user *user);
int shmlock_user_get(uid_t ruid, struct shmlock_user **userp);