* 2.4.19 ( try_to_swap_out) does not set page->mapping to NULL
@ 2002-12-13 3:29 Bourne
0 siblings, 0 replies; only message in thread
From: Bourne @ 2002-12-13 3:29 UTC (permalink / raw)
To: linux-kernel
Hi all, A small piece of code in mm/vmscan.c kept me confused. Please
could some one explain this ?
File: mm/vmscan.c , try_to_swap_out()
....SNIP....
drop_pte: mm->rss--
UnlockPage(page);
---SNIP--
page_cache_release(page);
return freeable;
----SNIP----
if(page->mapping)
goto drop_pte;
What i can get is if page->mapping is NOT NULL , then do a
page_cache_release(). This boils down to __free_pages_ok(). Here the
code snippet is if(page->mapping) BUG();
So if try_to_swap_out wants to drop a page which can be brought in
always ( i.e , not dirty ), then what is the harm in setting it to NULL ?
TIA
Bourne
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2002-12-13 3:29 2.4.19 ( try_to_swap_out) does not set page->mapping to NULL Bourne
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