On 08/17/2016 12:03 PM, Eric Dumazet wrote:

On Wed, 2016-08-17 at 11:20 -0700, Aruna Ramakrishna wrote:
]

quoted

-		list_for_each_entry(page, &n->slabs_full, lru) {
-			if (page->active != cachep->num && !error)
-				error = "slabs_full accounting error";
-			active_objs += cachep->num;
-			active_slabs++;
-		}

Since you only removed this loop, you could track only number of
full_slabs.

This would avoid messing with n->num_slabs all over the places in fast
path.

Please also update slab_out_of_memory()

Eric,

Right now, n->num_slabs is modified only when a slab is detached from 
slabs_free (i.e. in drain_freelist and free_block) or when a new one is 
attached in cache_grow_end. None of those 3 calls are in the fast path, 
right? Tracking just full_slabs would also involve similar changes: 
decrement when a slab moves from full to partial during free_block, and 
increment when it moves from partial/free to full after allocation in 
fixup_slab_list. So I don't see what the real difference/advantage is.

I will update slab_out_of_memory and remove the slabs_full list 
traversal there too.

Thanks,
Aruna


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