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mmu: add k_mem_free_get()

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Return the amount of physical anonymous memory remaining.

Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2020-12-18 11:50:58 -08:00 • committed by Anas Nashif
commit 5db615bb38
2 changed files with 27 additions and 0 deletions
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13
include/sys/mem_manage.h
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@ -138,6 +138,19 @@ void z_phys_map(uint8_t **virt_ptr, uintptr_t phys, size_t size,
*/ */
#define K_MEM_MAP_GUARD BIT(18) #define K_MEM_MAP_GUARD BIT(18)
/**
* Return the amount of free memory available
*
* The returned value will reflect how many free RAM page frames are available.
* If demand paging is enabled, it may still be possible to allocate more.
*
* The information reported by this function may go stale immediately if
* concurrent memory mappings or page-ins take place.
*
* @return Free physical RAM, in bytes
*/
size_t k_mem_free_get(void);
/** /**
* Map anonymous memory into Zephyr's address space * Map anonymous memory into Zephyr's address space
* *

14
kernel/mmu.c
View file

@ -363,6 +363,20 @@ out:
return dst; return dst;
} }
size_t k_mem_free_get(void)
{
size_t ret;
k_spinlock_key_t key;
__ASSERT(page_frames_initialized, "%s called too early", __func__);
key = k_spin_lock(&z_mm_lock);
ret = z_free_page_count;
k_spin_unlock(&z_mm_lock, key);
return ret * CONFIG_MMU_PAGE_SIZE;
}
/* This may be called from arch early boot code before z_cstart() is invoked. /* This may be called from arch early boot code before z_cstart() is invoked.
* Data will be copied and BSS zeroed, but this must not rely on any * Data will be copied and BSS zeroed, but this must not rely on any
* initialization functions being called prior to work correctly. * initialization functions being called prior to work correctly.