From: Vlastimil Babka vbabka@suse.cz
mainline inclusion from mainline-4.20-rc1 commit 2e03b4bc4ae84fcc0eee00e5ba5d228901d38809 category: bugfix bugzilla: 34611 CVE: NA
------------------------------------------------- We can use the newly introduced kmalloc-reclaimable-X caches, to allocate external names in dcache, which will take care of the proper accounting automatically, and also improve anti-fragmentation page grouping.
This effectively reverts commit f1782c9bc547 ("dcache: account external names as indirectly reclaimable memory") and instead passes __GFP_RECLAIMABLE to kmalloc(). The accounting thus moves from NR_INDIRECTLY_RECLAIMABLE_BYTES to NR_SLAB_RECLAIMABLE, which is also considered in MemAvailable calculation and overcommit decisions.
Link: http://lkml.kernel.org/r/20180731090649.16028-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka vbabka@suse.cz Acked-by: Mel Gorman mgorman@techsingularity.net Acked-by: Roman Gushchin guro@fb.com Cc: Christoph Lameter cl@linux.com Cc: David Rientjes rientjes@google.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Laura Abbott labbott@redhat.com Cc: Matthew Wilcox willy@infradead.org Cc: Michal Hocko mhocko@kernel.org Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Vijayanand Jitta vjitta@codeaurora.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org (cherry picked from commit 2e03b4bc4ae84fcc0eee00e5ba5d228901d38809) Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Liu Shixin liushixin2@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/dcache.c | 38 +++++++++----------------------------- 1 file changed, 9 insertions(+), 29 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c index 997c1efd5906..8b9841837274 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -257,24 +257,10 @@ static void __d_free(struct rcu_head *head) kmem_cache_free(dentry_cache, dentry); }
-static void __d_free_external_name(struct rcu_head *head) -{ - struct external_name *name = container_of(head, struct external_name, - u.head); - - mod_node_page_state(page_pgdat(virt_to_page(name)), - NR_INDIRECTLY_RECLAIMABLE_BYTES, - -ksize(name)); - - kfree(name); -} - static void __d_free_external(struct rcu_head *head) { struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); - - __d_free_external_name(&external_name(dentry)->u.head); - + kfree(external_name(dentry)); kmem_cache_free(dentry_cache, dentry); }
@@ -306,7 +292,7 @@ void release_dentry_name_snapshot(struct name_snapshot *name) struct external_name *p; p = container_of(name->name, struct external_name, name[0]); if (unlikely(atomic_dec_and_test(&p->u.count))) - call_rcu(&p->u.head, __d_free_external_name); + kfree_rcu(p, u.head); } } EXPORT_SYMBOL(release_dentry_name_snapshot); @@ -1643,7 +1629,6 @@ EXPORT_SYMBOL(d_invalidate);
struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) { - struct external_name *ext = NULL; struct dentry *dentry; char *dname; int err; @@ -1664,14 +1649,15 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) dname = dentry->d_iname; } else if (name->len > DNAME_INLINE_LEN-1) { size_t size = offsetof(struct external_name, name[1]); - - ext = kmalloc(size + name->len, GFP_KERNEL_ACCOUNT); - if (!ext) { + struct external_name *p = kmalloc(size + name->len, + GFP_KERNEL_ACCOUNT | + __GFP_RECLAIMABLE); + if (!p) { kmem_cache_free(dentry_cache, dentry); return NULL; } - atomic_set(&ext->u.count, 1); - dname = ext->name; + atomic_set(&p->u.count, 1); + dname = p->name; } else { dname = dentry->d_iname; } @@ -1711,12 +1697,6 @@ struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) } }
- if (unlikely(ext)) { - pg_data_t *pgdat = page_pgdat(virt_to_page(ext)); - mod_node_page_state(pgdat, NR_INDIRECTLY_RECLAIMABLE_BYTES, - ksize(ext)); - } - this_cpu_inc(nr_dentry);
return dentry; @@ -2773,7 +2753,7 @@ static void copy_name(struct dentry *dentry, struct dentry *target) dentry->d_name.hash_len = target->d_name.hash_len; } if (old_name && likely(atomic_dec_and_test(&old_name->u.count))) - call_rcu(&old_name->u.head, __d_free_external_name); + kfree_rcu(old_name, u.head); }
/*