delta/linux.git/include/linux/rhashtable.h, branch proc-cmdline

rhashtable: reorganize struct rhashtable layout

2018-04-01T03:25:39+00:00

While under frags DDOS I noticed unfortunate false sharing between
@nelems and @params.automatic_shrinking

Move @nelems at the end of struct rhashtable so that first cache line
is shared between all cpus, because almost never dirtied.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

rhashtable: Fix rhlist duplicates insertion

2018-03-07T15:44:02+00:00

When inserting duplicate objects (those with the same key),
current rhlist implementation messes up the chain pointers by
updating the bucket pointer instead of prev next pointer to the
newly inserted node. This causes missing elements on removal and
travesal.

Fix that by properly updating pprev pointer to point to
the correct rhash_head next pointer.

Issue: 1241076
Change-Id: I86b2c140bcb4aeb10b70a72a267ff590bb2b17e7
Fixes: ca26893f05e8 ('rhashtable: Add rhlist interface')
Signed-off-by: Paul Blakey 
Acked-by: Herbert Xu 
Signed-off-by: David S. Miller

rhashtable: abstract out function to get hash

2017-12-11T14:58:38+00:00

Split out most of rht_key_hashfn which is calculating the hash into
its own function. This way the hash function can be called separately to
get the hash value.

Acked-by: Thomas Graf 
Signed-off-by: Tom Herbert 
Signed-off-by: David S. Miller

rhashtable: Add rhastable_walk_peek

2017-12-11T14:58:38+00:00

This function is like rhashtable_walk_next except that it only returns
the current element in the inter and does not advance the iter.

This patch also creates __rhashtable_walk_find_next. It finds the next
element in the table when the entry cached in iter is NULL or at the end
of a slot. __rhashtable_walk_find_next is called from
rhashtable_walk_next and rhastable_walk_peek.

end_of_table is an added field to the iter structure. This indicates
that the end of table was reached (walker.tbl being NULL is not a
sufficient condition for end of table).

Signed-off-by: Tom Herbert 
Acked-by: Herbert Xu 
Signed-off-by: David S. Miller

rhashtable: Change rhashtable_walk_start to return void

2017-12-11T14:58:38+00:00

Most callers of rhashtable_walk_start don't care about a resize event
which is indicated by a return value of -EAGAIN. So calls to
rhashtable_walk_start are wrapped wih code to ignore -EAGAIN. Something
like this is common:

       ret = rhashtable_walk_start(rhiter);
       if (ret && ret != -EAGAIN)
               goto out;

Since zero and -EAGAIN are the only possible return values from the
function this check is pointless. The condition never evaluates to true.

This patch changes rhashtable_walk_start to return void. This simplifies
code for the callers that ignore -EAGAIN. For the few cases where the
caller cares about the resize event, particularly where the table can be
walked in mulitple parts for netlink or seq file dump, the function
rhashtable_walk_start_check has been added that returns -EAGAIN on a
resize event.

Signed-off-by: Tom Herbert 
Acked-by: Herbert Xu 
Signed-off-by: David S. Miller

lib/rhashtable: fix comment on locks_mul default value

2017-09-09T01:26:49+00:00

As of commit 4cf0b354d92 ("rhashtable: avoid large lock-array
allocations"), the default value for the locks multiplier was reduced
from 128 to 32.

Update the header file to reflect this.

Link: http://lkml.kernel.org/r/20170815215401.30745-1-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso 
Cc: Florian Westphal 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rhashtable: compact struct rhashtable_params

2017-05-01T20:22:40+00:00

By using smaller datatypes this (rather large) struct shrinks considerably
(80 -> 48 bytes on x86_64).

As this is embedded in other structs, this also rerduces size of several
others, e.g. cls_fl_head or nft_hash.

Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller

rhashtable: Cap total number of entries to 2^31

2017-04-27T15:48:24+00:00

When max_size is not set or if it set to a sufficiently large
value, the nelems counter can overflow.  This would cause havoc
with the automatic shrinking as it would then attempt to fit a
huge number of entries into a tiny hash table.

This patch fixes this by adding max_elems to struct rhashtable
to cap the number of elements.  This is set to 2^31 as nelems is
not a precise count.  This is sufficiently smaller than UINT_MAX
that it should be safe.

When max_size is set max_elems will be lowered to at most twice
max_size as is the status quo.

Signed-off-by: Herbert Xu 
Signed-off-by: David S. Miller

rhashtable: remove insecure_max_entries param

2017-04-26T18:39:24+00:00

no users in the tree, insecure_max_entries is always set to
ht->p.max_size * 2 in rhtashtable_init().

Replace only spot that uses it with a ht->p.max_size check.

Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller

rhashtable: remove insecure_elasticity

2017-04-18T17:49:14+00:00

commit 83e7e4ce9e93c3 ("mac80211: Use rhltable instead of rhashtable")
removed the last user that made use of 'insecure_elasticity' parameter,
i.e. the default of 16 is used everywhere.

Replace it with a constant.

Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller