Messages in this thread | | | Subject | Re: [PATCH v6 6/6] locking/lockdep: Reuse freed chain_hlocks entries | From | Waiman Long <> | Date | Thu, 6 Feb 2020 12:08:20 -0500 |
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On 2/6/20 11:16 AM, Peter Zijlstra wrote: > On Thu, Feb 06, 2020 at 10:24:08AM -0500, Waiman Long wrote: >> +static int alloc_chain_hlocks(int req) >> +{ >> + int bucket, curr, size; >> + >> + /* >> + * We rely on the MSB to act as an escape bit to denote freelist >> + * pointers. Make sure this bit isn't set in 'normal' class_idx usage. >> + */ >> + BUILD_BUG_ON((MAX_LOCKDEP_KEYS-1) & CHAIN_BLK_FLAG); >> + >> + init_data_structures_once(); >> + >> + if (nr_free_chain_hlocks < req) >> + return -1; >> + >> + /* >> + * We require a minimum of 2 (u16) entries to encode a freelist >> + * 'pointer'. >> + */ >> + req = max(req, 2); >> + bucket = size_to_bucket(req); >> + curr = chain_block_buckets[bucket]; >> + >> + if (bucket && (curr >= 0)) { >> + del_chain_block(bucket, req, chain_block_next(curr)); >> + return curr; >> + } else if (bucket) { >> + /* Try bucket 0 */ >> + curr = chain_block_buckets[0]; >> + } > if (bucket) { > if (curr >= 0) { > del_chain_block(bucket, req, chain_block_next(curr)); > return curr; > } > /* Try bucket 0 */ > curr = chain_block_bucket[0]; > } > > reads much easier IMO.
Yes, that is simpler. I can send out an updated patch if you want, or you can apply the change when you pull the patch.
Thanks, Longman
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