[PATCH v7 4/4] hugetlb: allow to free gigantic pages regardless of the configuration
Alex Ghiti
alex at ghiti.fr
Mon Mar 18 18:00:47 AEDT 2019
On 3/17/19 2:31 PM, christophe leroy wrote:
>
>
> Le 17/03/2019 à 17:28, Alexandre Ghiti a écrit :
>> On systems without CONTIG_ALLOC activated but that support gigantic
>> pages,
>> boottime reserved gigantic pages can not be freed at all. This patch
>> simply enables the possibility to hand back those pages to memory
>> allocator.
>>
>> Signed-off-by: Alexandre Ghiti <alex at ghiti.fr>
>> Acked-by: David S. Miller <davem at davemloft.net> [sparc]
>> ---
>> arch/arm64/Kconfig | 2 +-
>> arch/arm64/include/asm/hugetlb.h | 4 --
>> arch/powerpc/include/asm/book3s/64/hugetlb.h | 7 ---
>> arch/powerpc/platforms/Kconfig.cputype | 2 +-
>> arch/s390/Kconfig | 2 +-
>> arch/s390/include/asm/hugetlb.h | 3 --
>> arch/sh/Kconfig | 2 +-
>> arch/sparc/Kconfig | 2 +-
>> arch/x86/Kconfig | 2 +-
>> arch/x86/include/asm/hugetlb.h | 4 --
>> include/asm-generic/hugetlb.h | 14 +++++
>> include/linux/gfp.h | 2 +-
>> mm/hugetlb.c | 54 ++++++++++++++------
>> mm/page_alloc.c | 4 +-
>> 14 files changed, 61 insertions(+), 43 deletions(-)
>>
>
> [...]
>
>> diff --git a/include/asm-generic/hugetlb.h
>> b/include/asm-generic/hugetlb.h
>> index 71d7b77eea50..aaf14974ee5f 100644
>> --- a/include/asm-generic/hugetlb.h
>> +++ b/include/asm-generic/hugetlb.h
>> @@ -126,4 +126,18 @@ static inline pte_t huge_ptep_get(pte_t *ptep)
>> }
>> #endif
>> +#ifndef __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED
>> +#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
>> +static inline bool gigantic_page_runtime_supported(void)
>> +{
>> + return true;
>> +}
>> +#else
>> +static inline bool gigantic_page_runtime_supported(void)
>> +{
>> + return false;
>> +}
>> +#endif /* CONFIG_ARCH_HAS_GIGANTIC_PAGE */
>
> What about the following instead:
>
> static inline bool gigantic_page_runtime_supported(void)
> {
> return IS_ENABLED(CONFIG_ARCH_HAS_GIGANTIC_PAGE);
> }
>
Totally, it already was like that in v2 or v3...
>
>> +#endif /* __HAVE_ARCH_GIGANTIC_PAGE_RUNTIME_SUPPORTED */
>> +
>> #endif /* _ASM_GENERIC_HUGETLB_H */
>> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
>> index 1f1ad9aeebb9..58ea44bf75de 100644
>> --- a/include/linux/gfp.h
>> +++ b/include/linux/gfp.h
>> @@ -589,8 +589,8 @@ static inline bool pm_suspended_storage(void)
>> /* The below functions must be run on a range from a single zone. */
>> extern int alloc_contig_range(unsigned long start, unsigned long end,
>> unsigned migratetype, gfp_t gfp_mask);
>> -extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
>> #endif
>> +extern void free_contig_range(unsigned long pfn, unsigned int
>> nr_pages);
>
> 'extern' is unneeded and should be avoided (iaw checkpatch)
>
Ok, I did fix a checkpatch warning here, but did not notice the 'extern'
one.
Thanks for your time,
Alex
> Christophe
>
>> #ifdef CONFIG_CMA
>> /* CMA stuff */
>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>> index afef61656c1e..4e55aa38704f 100644
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -1058,6 +1058,7 @@ static void free_gigantic_page(struct page
>> *page, unsigned int order)
>> free_contig_range(page_to_pfn(page), 1 << order);
>> }
>> +#ifdef CONFIG_CONTIG_ALLOC
>> static int __alloc_gigantic_page(unsigned long start_pfn,
>> unsigned long nr_pages, gfp_t gfp_mask)
>> {
>> @@ -1142,11 +1143,20 @@ static struct page
>> *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
>> static void prep_new_huge_page(struct hstate *h, struct page
>> *page, int nid);
>> static void prep_compound_gigantic_page(struct page *page, unsigned
>> int order);
>> +#else /* !CONFIG_CONTIG_ALLOC */
>> +static struct page *alloc_gigantic_page(struct hstate *h, gfp_t
>> gfp_mask,
>> + int nid, nodemask_t *nodemask)
>> +{
>> + return NULL;
>> +}
>> +#endif /* CONFIG_CONTIG_ALLOC */
>> #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
>> -static inline bool gigantic_page_supported(void) { return false; }
>> static struct page *alloc_gigantic_page(struct hstate *h, gfp_t
>> gfp_mask,
>> - int nid, nodemask_t *nodemask) { return NULL; }
>> + int nid, nodemask_t *nodemask)
>> +{
>> + return NULL;
>> +}
>> static inline void free_gigantic_page(struct page *page, unsigned
>> int order) { }
>> static inline void destroy_compound_gigantic_page(struct page *page,
>> unsigned int order) { }
>> @@ -1156,7 +1166,7 @@ static void update_and_free_page(struct hstate
>> *h, struct page *page)
>> {
>> int i;
>> - if (hstate_is_gigantic(h) && !gigantic_page_supported())
>> + if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
>> return;
>> h->nr_huge_pages--;
>> @@ -2276,13 +2286,27 @@ static int adjust_pool_surplus(struct hstate
>> *h, nodemask_t *nodes_allowed,
>> }
>> #define persistent_huge_pages(h) (h->nr_huge_pages -
>> h->surplus_huge_pages)
>> -static unsigned long set_max_huge_pages(struct hstate *h, unsigned
>> long count,
>> - nodemask_t *nodes_allowed)
>> +static int set_max_huge_pages(struct hstate *h, unsigned long count,
>> + nodemask_t *nodes_allowed)
>> {
>> unsigned long min_count, ret;
>> - if (hstate_is_gigantic(h) && !gigantic_page_supported())
>> - return h->max_huge_pages;
>> + spin_lock(&hugetlb_lock);
>> +
>> + /*
>> + * Gigantic pages runtime allocation depend on the capability
>> for large
>> + * page range allocation.
>> + * If the system does not provide this feature, return an error
>> when
>> + * the user tries to allocate gigantic pages but let the user
>> free the
>> + * boottime allocated gigantic pages.
>> + */
>> + if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
>> + if (count > persistent_huge_pages(h)) {
>> + spin_unlock(&hugetlb_lock);
>> + return -EINVAL;
>> + }
>> + /* Fall through to decrease pool */
>> + }
>> /*
>> * Increase the pool size
>> @@ -2295,7 +2319,6 @@ static unsigned long set_max_huge_pages(struct
>> hstate *h, unsigned long count,
>> * pool might be one hugepage larger than it needs to be, but
>> * within all the constraints specified by the sysctls.
>> */
>> - spin_lock(&hugetlb_lock);
>> while (h->surplus_huge_pages && count >
>> persistent_huge_pages(h)) {
>> if (!adjust_pool_surplus(h, nodes_allowed, -1))
>> break;
>> @@ -2350,9 +2373,10 @@ static unsigned long set_max_huge_pages(struct
>> hstate *h, unsigned long count,
>> break;
>> }
>> out:
>> - ret = persistent_huge_pages(h);
>> + h->max_huge_pages = persistent_huge_pages(h);
>> spin_unlock(&hugetlb_lock);
>> - return ret;
>> +
>> + return 0;
>> }
>> #define HSTATE_ATTR_RO(_name) \
>> @@ -2404,7 +2428,7 @@ static ssize_t __nr_hugepages_store_common(bool
>> obey_mempolicy,
>> int err;
>> NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL |
>> __GFP_NORETRY);
>> - if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
>> + if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) {
>> err = -EINVAL;
>> goto out;
>> }
>> @@ -2428,15 +2452,13 @@ static ssize_t
>> __nr_hugepages_store_common(bool obey_mempolicy,
>> } else
>> nodes_allowed = &node_states[N_MEMORY];
>> - h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
>> + err = set_max_huge_pages(h, count, nodes_allowed);
>> +out:
>> if (nodes_allowed != &node_states[N_MEMORY])
>> NODEMASK_FREE(nodes_allowed);
>> - return len;
>> -out:
>> - NODEMASK_FREE(nodes_allowed);
>> - return err;
>> + return err ? err : len;
>> }
>> static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>> index ac9c45ffb344..a4547d90fa7a 100644
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -8234,8 +8234,9 @@ int alloc_contig_range(unsigned long start,
>> unsigned long end,
>> pfn_max_align_up(end), migratetype);
>> return ret;
>> }
>> +#endif /* CONFIG_CONTIG_ALLOC */
>> -void free_contig_range(unsigned long pfn, unsigned nr_pages)
>> +void free_contig_range(unsigned long pfn, unsigned int nr_pages)
>> {
>> unsigned int count = 0;
>> @@ -8247,7 +8248,6 @@ void free_contig_range(unsigned long pfn,
>> unsigned nr_pages)
>> }
>> WARN(count != 0, "%d pages are still in use!\n", count);
>> }
>> -#endif
>> #ifdef CONFIG_MEMORY_HOTPLUG
>> /*
>>
>
> ---
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> logiciel antivirus Avast.
> https://www.avast.com/antivirus
>
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