Revision 3ad33b2436b545cbe8b28e53f3710432cad457ab authored by Lee Schermerhorn on 15 November 2007, 00:59:10 UTC, committed by Linus Torvalds on 15 November 2007, 02:45:38 UTC
We hit the BUG_ON() in mm/rmap.c:vma_address() when trying to migrate via mbind(MPOL_MF_MOVE) a non-anon region that spans multiple vmas. For anon-regions, we just fail to migrate any pages beyond the 1st vma in the range. This occurs because do_mbind() collects a list of pages to migrate by calling check_range(). check_range() walks the task's mm, spanning vmas as necessary, to collect the migratable pages into a list. Then, do_mbind() calls migrate_pages() passing the list of pages, a function to allocate new pages based on vma policy [new_vma_page()], and a pointer to the first vma of the range. For each page in the list, new_vma_page() calls page_address_in_vma() passing the page and the vma [first in range] to obtain the address to get for alloc_page_vma(). The page address is needed to get interleaving policy correct. If the pages in the list come from multiple vmas, eventually, new_page_address() will pass that page to page_address_in_vma() with the incorrect vma. For !PageAnon pages, this will result in a bug check in rmap.c:vma_address(). For anon pages, vma_address() will just return EFAULT and fail the migration. This patch modifies new_vma_page() to check the return value from page_address_in_vma(). If the return value is EFAULT, new_vma_page() searchs forward via vm_next for the vma that maps the page--i.e., that does not return EFAULT. This assumes that the pages in the list handed to migrate_pages() is in address order. This is currently case. The patch documents this assumption in a new comment block for new_vma_page(). If new_vma_page() cannot locate the vma mapping the page in a forward search in the mm, it will pass a NULL vma to alloc_page_vma(). This will result in the allocation using the task policy, if any, else system default policy. This situation is unlikely, but the patch documents this behavior with a comment. Note, this patch results in restarting from the first vma in a multi-vma range each time new_vma_page() is called. If this is not acceptable, we can make the vma argument a pointer, both in new_vma_page() and it's caller unmap_and_move() so that the value held by the loop in migrate_pages() always passes down the last vma in which a page was found. This will require changes to all new_page_t functions passed to migrate_pages(). Is this necessary? For this patch to work, we can't bug check in vma_address() for pages outside the argument vma. This patch removes the BUG_ON(). All other callers [besides new_vma_page()] already check the return status. Tested on x86_64, 4 node NUMA platform. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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File | Mode | Size |
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platform | ||
acconfig.h | -rw-r--r-- | 7.2 KB |
acdebug.h | -rw-r--r-- | 6.5 KB |
acdisasm.h | -rw-r--r-- | 12.9 KB |
acdispat.h | -rw-r--r-- | 10.8 KB |
acevents.h | -rw-r--r-- | 6.5 KB |
acexcep.h | -rw-r--r-- | 13.0 KB |
acglobal.h | -rw-r--r-- | 13.5 KB |
achware.h | -rw-r--r-- | 4.2 KB |
acinterp.h | -rw-r--r-- | 15.9 KB |
aclocal.h | -rw-r--r-- | 31.2 KB |
acmacros.h | -rw-r--r-- | 27.6 KB |
acnames.h | -rw-r--r-- | 3.4 KB |
acnamesp.h | -rw-r--r-- | 9.2 KB |
acobject.h | -rw-r--r-- | 15.3 KB |
acopcode.h | -rw-r--r-- | 21.8 KB |
acoutput.h | -rw-r--r-- | 8.0 KB |
acparser.h | -rw-r--r-- | 7.2 KB |
acpi.h | -rw-r--r-- | 3.1 KB |
acpi_bus.h | -rw-r--r-- | 10.4 KB |
acpi_drivers.h | -rw-r--r-- | 5.3 KB |
acpi_numa.h | -rw-r--r-- | 522 bytes |
acpiosxf.h | -rw-r--r-- | 7.8 KB |
acpixf.h | -rw-r--r-- | 9.6 KB |
acresrc.h | -rw-r--r-- | 10.8 KB |
acstruct.h | -rw-r--r-- | 7.6 KB |
actables.h | -rw-r--r-- | 4.0 KB |
actbl.h | -rw-r--r-- | 14.1 KB |
actbl1.h | -rw-r--r-- | 19.9 KB |
actypes.h | -rw-r--r-- | 35.7 KB |
acutils.h | -rw-r--r-- | 16.8 KB |
amlcode.h | -rw-r--r-- | 18.5 KB |
amlresrc.h | -rw-r--r-- | 9.7 KB |
container.h | -rw-r--r-- | 198 bytes |
pdc_intel.h | -rw-r--r-- | 935 bytes |
processor.h | -rw-r--r-- | 8.5 KB |
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