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Subject: RE: [PATCH v8 07/15] x86/sgx: Expose sgx_reclaim_pages() for cgroup
Thread-Topic: [PATCH v8 07/15] x86/sgx: Expose sgx_reclaim_pages() for cgroup
Thread-Index: AQHaUyGZchgotqjrFkClyK7aZR52grDyfC3w
Date: Tue, 30 Jan 2024 15:39:44 +0000
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References: <20240130020938.10025-1-haitao.huang@linux.intel.com>
 <20240130020938.10025-8-haitao.huang@linux.intel.com>
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> + * @lru:	The LRU from which pages are reclaimed.
> + * @nr_to_scan: Pointer to the target number of pages to scan, must be l=
ess
> than
> + *		SGX_NR_TO_SCAN.
> + * Return:	Number of pages reclaimed.
>   */
> -static void sgx_reclaim_pages(void)
> +unsigned int sgx_reclaim_pages(struct sgx_epc_lru_list *lru, unsigned
> +int *nr_to_scan)

Since the function is now returning the number of reclaimed pages, why do y=
ou need to make the @nr_to_scan as pointer?

Cannot the caller just adjust @nr_to_scan when calling this function based =
on how many pages have reclaimed?

I am not even sure whether you need @nr_to_scan at all because as we discus=
sed I think it's just extremely rare you need to pass "< SGX_NR_TO_SCAN" to=
 this function.

Even if you need, you can always choose to try to reclaim SGX_NR_TO_SCAN pa=
ges.

[...]

>=20
> +static void sgx_reclaim_pages_global(void) {
> +	unsigned int nr_to_scan =3D SGX_NR_TO_SCAN;
> +
> +	sgx_reclaim_pages(&sgx_global_lru, &nr_to_scan); }
> +

I think this function doesn't look sane at all when you have @nr_to_scan be=
ing a pointer?

I am also not sure whether this function is needed -- if we don't add @nr_t=
o_scan to sgx_reclaim_pages(), then this function is basically:

	sgx_reclaim_pages(&sgx_global_lru);=20