mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-25 21:54:06 +08:00
Revert "mm/z3fold.c: fix race between migration and destruction"
With the original commit applied, z3fold_zpool_destroy() may get blocked
on wait_event() for indefinite time. Revert this commit for the time
being to get rid of this problem since the issue the original commit
addresses is less severe.
Link: http://lkml.kernel.org/r/20190910123142.7a9c8d2de4d0acbc0977c602@gmail.com
Fixes: d776aaa989
("mm/z3fold.c: fix race between migration and destruction")
Reported-by: Agustín Dall'Alba <agustin@dallalba.com.ar>
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Adams <jwadams@google.com>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
07bfa4415a
commit
6e73fd25e2
90
mm/z3fold.c
90
mm/z3fold.c
@ -41,7 +41,6 @@
|
||||
#include <linux/workqueue.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/spinlock.h>
|
||||
#include <linux/wait.h>
|
||||
#include <linux/zpool.h>
|
||||
#include <linux/magic.h>
|
||||
|
||||
@ -146,8 +145,6 @@ struct z3fold_header {
|
||||
* @release_wq: workqueue for safe page release
|
||||
* @work: work_struct for safe page release
|
||||
* @inode: inode for z3fold pseudo filesystem
|
||||
* @destroying: bool to stop migration once we start destruction
|
||||
* @isolated: int to count the number of pages currently in isolation
|
||||
*
|
||||
* This structure is allocated at pool creation time and maintains metadata
|
||||
* pertaining to a particular z3fold pool.
|
||||
@ -166,11 +163,8 @@ struct z3fold_pool {
|
||||
const struct zpool_ops *zpool_ops;
|
||||
struct workqueue_struct *compact_wq;
|
||||
struct workqueue_struct *release_wq;
|
||||
struct wait_queue_head isolate_wait;
|
||||
struct work_struct work;
|
||||
struct inode *inode;
|
||||
bool destroying;
|
||||
int isolated;
|
||||
};
|
||||
|
||||
/*
|
||||
@ -775,7 +769,6 @@ static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
|
||||
goto out_c;
|
||||
spin_lock_init(&pool->lock);
|
||||
spin_lock_init(&pool->stale_lock);
|
||||
init_waitqueue_head(&pool->isolate_wait);
|
||||
pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2);
|
||||
if (!pool->unbuddied)
|
||||
goto out_pool;
|
||||
@ -815,15 +808,6 @@ out:
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static bool pool_isolated_are_drained(struct z3fold_pool *pool)
|
||||
{
|
||||
bool ret;
|
||||
|
||||
spin_lock(&pool->lock);
|
||||
ret = pool->isolated == 0;
|
||||
spin_unlock(&pool->lock);
|
||||
return ret;
|
||||
}
|
||||
/**
|
||||
* z3fold_destroy_pool() - destroys an existing z3fold pool
|
||||
* @pool: the z3fold pool to be destroyed
|
||||
@ -833,22 +817,6 @@ static bool pool_isolated_are_drained(struct z3fold_pool *pool)
|
||||
static void z3fold_destroy_pool(struct z3fold_pool *pool)
|
||||
{
|
||||
kmem_cache_destroy(pool->c_handle);
|
||||
/*
|
||||
* We set pool-> destroying under lock to ensure that
|
||||
* z3fold_page_isolate() sees any changes to destroying. This way we
|
||||
* avoid the need for any memory barriers.
|
||||
*/
|
||||
|
||||
spin_lock(&pool->lock);
|
||||
pool->destroying = true;
|
||||
spin_unlock(&pool->lock);
|
||||
|
||||
/*
|
||||
* We need to ensure that no pages are being migrated while we destroy
|
||||
* these workqueues, as migration can queue work on either of the
|
||||
* workqueues.
|
||||
*/
|
||||
wait_event(pool->isolate_wait, !pool_isolated_are_drained(pool));
|
||||
|
||||
/*
|
||||
* We need to destroy pool->compact_wq before pool->release_wq,
|
||||
@ -1339,28 +1307,6 @@ static u64 z3fold_get_pool_size(struct z3fold_pool *pool)
|
||||
return atomic64_read(&pool->pages_nr);
|
||||
}
|
||||
|
||||
/*
|
||||
* z3fold_dec_isolated() expects to be called while pool->lock is held.
|
||||
*/
|
||||
static void z3fold_dec_isolated(struct z3fold_pool *pool)
|
||||
{
|
||||
assert_spin_locked(&pool->lock);
|
||||
VM_BUG_ON(pool->isolated <= 0);
|
||||
pool->isolated--;
|
||||
|
||||
/*
|
||||
* If we have no more isolated pages, we have to see if
|
||||
* z3fold_destroy_pool() is waiting for a signal.
|
||||
*/
|
||||
if (pool->isolated == 0 && waitqueue_active(&pool->isolate_wait))
|
||||
wake_up_all(&pool->isolate_wait);
|
||||
}
|
||||
|
||||
static void z3fold_inc_isolated(struct z3fold_pool *pool)
|
||||
{
|
||||
pool->isolated++;
|
||||
}
|
||||
|
||||
static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode)
|
||||
{
|
||||
struct z3fold_header *zhdr;
|
||||
@ -1387,34 +1333,6 @@ static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode)
|
||||
spin_lock(&pool->lock);
|
||||
if (!list_empty(&page->lru))
|
||||
list_del(&page->lru);
|
||||
/*
|
||||
* We need to check for destruction while holding pool->lock, as
|
||||
* otherwise destruction could see 0 isolated pages, and
|
||||
* proceed.
|
||||
*/
|
||||
if (unlikely(pool->destroying)) {
|
||||
spin_unlock(&pool->lock);
|
||||
/*
|
||||
* If this page isn't stale, somebody else holds a
|
||||
* reference to it. Let't drop our refcount so that they
|
||||
* can call the release logic.
|
||||
*/
|
||||
if (unlikely(kref_put(&zhdr->refcount,
|
||||
release_z3fold_page_locked))) {
|
||||
/*
|
||||
* If we get here we have kref problems, so we
|
||||
* should freak out.
|
||||
*/
|
||||
WARN(1, "Z3fold is experiencing kref problems\n");
|
||||
z3fold_page_unlock(zhdr);
|
||||
return false;
|
||||
}
|
||||
z3fold_page_unlock(zhdr);
|
||||
return false;
|
||||
}
|
||||
|
||||
|
||||
z3fold_inc_isolated(pool);
|
||||
spin_unlock(&pool->lock);
|
||||
z3fold_page_unlock(zhdr);
|
||||
return true;
|
||||
@ -1483,10 +1401,6 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa
|
||||
|
||||
queue_work_on(new_zhdr->cpu, pool->compact_wq, &new_zhdr->work);
|
||||
|
||||
spin_lock(&pool->lock);
|
||||
z3fold_dec_isolated(pool);
|
||||
spin_unlock(&pool->lock);
|
||||
|
||||
page_mapcount_reset(page);
|
||||
put_page(page);
|
||||
return 0;
|
||||
@ -1506,14 +1420,10 @@ static void z3fold_page_putback(struct page *page)
|
||||
INIT_LIST_HEAD(&page->lru);
|
||||
if (kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
|
||||
atomic64_dec(&pool->pages_nr);
|
||||
spin_lock(&pool->lock);
|
||||
z3fold_dec_isolated(pool);
|
||||
spin_unlock(&pool->lock);
|
||||
return;
|
||||
}
|
||||
spin_lock(&pool->lock);
|
||||
list_add(&page->lru, &pool->lru);
|
||||
z3fold_dec_isolated(pool);
|
||||
spin_unlock(&pool->lock);
|
||||
z3fold_page_unlock(zhdr);
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user