33 lines
1.3 KiB
Plaintext
33 lines
1.3 KiB
Plaintext
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Variables
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bool trimming_cycle;
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Do we need free space?
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static addr free_memory_low_water;
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static addr free_memory_high_water;
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static void scan_pages(vm_address_space *aspace, addr free_target)
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Finds a region in this address space to scan.
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Locks the region's cache_ref.
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For each page,
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if the page is present, do nothing with this page
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Lookup the page structure. If this page doesn't exist, do nothing with this page.
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If the page is written to or is hard wired (unswapable), do nothing with it.
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If the page is not accessed and is active and we need space (free_target), unmap it. If this is the last reference to that mapped page, put it on the inactive list.
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If the page has been modified, but wasn't on the active list, put it there.
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Move to the next region in this address space, wrap around until we hit the first one.
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static int page_daemon()
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Walk through every address space:
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Adjust the size of the processes' working set (i.e. memory allocation) to be larger or smaller, to tailor to faults.
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Set trimming cycle if free pages is below the high water mark.
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Clear trimming cycle if free pages is above high water mark.
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Set free memory target to be the processes' mapped size minus the working set
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Call scan_pages
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int vm_daemon_init()
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Sets high water to pages/4 and low water to pages/8.
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Creates the page daemon as a kernel thread.
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