Re: [RFC][PATCH] radix-tree based page_cgroup. [7/7] per cpu fast lookup

[yamamoto@valinux.co.jp (YAMAMOTO Takashi)]

> +
> +static void save_result(struct page_cgroup  *base, unsigned long idx)
> +{
> +	int hash = idx & (PAGE_CGROUP_NR_CACHE - 1);
> +	struct page_cgroup_cache *pcp = &__get_cpu_var(pcpu_page_cgroup_cache);
> +	preempt_disable();
> +	pcp->ents[hash].idx = idx;
> +	pcp->ents[hash].base = base;
> +	preempt_enable();

preempt_disable after __get_cpu_var doesn't make much sense.
it should be get_cpu_var and put_cpu_var.

> -struct page_cgroup *get_page_cgroup(struct page *page, gfp_t gfpmask);
> +struct page_cgroup *__get_page_cgroup(struct page *page, gfp_t gfpmask);
> +
> +static inline struct page_cgroup *
> +get_page_cgroup(struct page *page, gfp_t gfpmask)
> +{
> +	unsigned long pfn = page_to_pfn(page);
> +	struct page_cgroup_cache *pcp = &__get_cpu_var(pcpu_page_cgroup_cache);
> +	struct page_cgroup *ret;
> +	unsigned long idx = pfn >> PCGRP_SHIFT;
> +	int hnum = (idx) & (PAGE_CGROUP_NR_CACHE - 1);
> +
> +	preempt_disable();
> +	if (pcp->ents[hnum].idx == idx && pcp->ents[hnum].base)
> +		ret = pcp->ents[hnum].base + (pfn - (idx << PCGRP_SHIFT));
> +	else
> +		ret = NULL;
> +	preempt_enable();

ditto.

YAMAMOTO Takashi

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