Commit 2e03b4bc authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
Browse files

dcache: allocate external names from reclaimable kmalloc caches 

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 f1782c9b ("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: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarMel Gorman <mgorman@techsingularity.net>
Acked-by: default avatarRoman 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1291523f

fs/dcache.c

+9 −29
Original line number Diff line number Diff line
@@ -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);
@@ -1606,7 +1592,6 @@ 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;
@@ -1627,14 +1612,15 @@ 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;

	}
@@ -1673,12 +1659,6 @@ 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;
@@ -2707,7 +2687,7 @@ 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);

}



/*

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