Subject: Re: [PATCH v3 4/4] read-cache: speed up index load through parallelization

From: Torsten Bögershausen <[email-masked]>
Date: Fri, 7 Sep 2018 06:16:57 +0200

> diff --git a/read-cache.c b/read-cache.c
> index fcc776aaf0..8537a55750 100644
> --- a/read-cache.c
> +++ b/read-cache.c
> @@ -1941,20 +1941,212 @@ static void *load_index_extensions(void *_data)
>  	return NULL;
>  }
>  
> +/*
> + * A helper function that will load the specified range of cache entries
> + * from the memory mapped file and add them to the given index.
> + */
> +static unsigned long load_cache_entry_block(struct index_state *istate,
> +			struct mem_pool *ce_mem_pool, int offset, int nr, void *mmap,
> +			unsigned long start_offset, struct strbuf *previous_name)
> +{
> +	int i;
> +	unsigned long src_offset = start_offset;

I read an unsigned long here:
should that be a size_t instead ?

(And probably even everywhere else in this patch)

> +
> +	for (i = offset; i < offset + nr; i++) {
> +		struct ondisk_cache_entry *disk_ce;
> +		struct cache_entry *ce;
> +		unsigned long consumed;
> +
> +		disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
> +		ce = create_from_disk(ce_mem_pool, disk_ce, &consumed, previous_name);
> +		set_index_entry(istate, i, ce);
> +
> +		src_offset += consumed;
> +	}
> +	return src_offset - start_offset;
> +}
> +
> +static unsigned long load_all_cache_entries(struct index_state *istate,
> +			void *mmap, size_t mmap_size, unsigned long src_offset)
> +{
> +	struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
> +	unsigned long consumed;
> +
> +	if (istate->version == 4) {
> +		previous_name = &previous_name_buf;
> +		mem_pool_init(&istate->ce_mem_pool,
> +				estimate_cache_size_from_compressed(istate->cache_nr));
> +	} else {
> +		previous_name = NULL;
> +		mem_pool_init(&istate->ce_mem_pool,
> +				estimate_cache_size(mmap_size, istate->cache_nr));
> +	}
> +
> +	consumed = load_cache_entry_block(istate, istate->ce_mem_pool,
> +					0, istate->cache_nr, mmap, src_offset, previous_name);
> +	strbuf_release(&previous_name_buf);
> +	return consumed;
> +}
> +
> +#ifndef NO_PTHREADS
> +