From: Steven Walter <stevenrwalter@gmail.com>
To: linux-mm@kvack.org
Subject: Erroneous VM_MINOR_FAULT return from filemap_fault?
Date: Thu, 3 Jan 2008 15:24:06 -0500 [thread overview]
Message-ID: <20080103202406.GA30573@dervierte> (raw)
There appears to be a path through filemap_fault such that the function
returns VM_MINOR_FAULT, even though disk IO was performed. Suppose that
the page in question is not already in the page cache (find_lock_page
returns NULL) and we trip the MMAP_LOTSAMISS logic, ending up at
no_cached_page. Immediately page_cache_read is called, but ret was
never set to VM_MAJOR_FAULT (still at the default of VM_MINOR_FAULT).
Control jumps back to retry_find, find_lock_page returns the page, and
eventually the function returns VM_MINOR_FAULT.
Is there some assumption I'm missing where the execution path I
summarized couldn't actually happen? Perhaps this behavior is
intentional? Certainly it seems that if IO is performed, the fault
should be considered a major fault.
--
-Steven Walter <stevenrwalter@gmail.com>
Freedom is the freedom to say that 2 + 2 = 4
B2F1 0ECC E605 7321 E818 7A65 FC81 9777 DC28 9E8F
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reply other threads:[~2008-01-03 20:24 UTC|newest]
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