mirror of
https://github.com/torvalds/linux.git
synced 2024-11-11 06:31:49 +00:00
304dbdb7a4
Basic problem: pages of a shared memory segment can only be migrated once. In 2.6.16 through 2.6.17-rc1, shared memory mappings do not have a migratepage address space op. Therefore, migrate_pages() falls back to default processing. In this path, it will try to pageout() dirty pages. Once a shared memory page has been migrated it becomes dirty, so migrate_pages() will try to page it out. However, because the page count is 3 [cache + current + pte], pageout() will return PAGE_KEEP because is_page_cache_freeable() returns false. This will abort all subsequent migrations. This patch adds a migratepage address space op to shared memory segments to avoid taking the default path. We use the "migrate_page()" function because it knows how to migrate dirty pages. This allows shared memory segment pages to migrate, subject to other conditions such as # pte's referencing the page [page_mapcount(page)], when requested. I think this is safe. If we're migrating a shared memory page, then we found the page via a page table, so it must be in memory. Can be verified with memtoy and the shmem-mbind-test script, both available at: http://free.linux.hp.com/~lts/Tools/ Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
||
|---|---|---|
| .. | ||
| bootmem.c | ||
| fadvise.c | ||
| filemap_xip.c | ||
| filemap.c | ||
| filemap.h | ||
| fremap.c | ||
| highmem.c | ||
| hugetlb.c | ||
| internal.h | ||
| Kconfig | ||
| madvise.c | ||
| Makefile | ||
| memory_hotplug.c | ||
| memory.c | ||
| mempolicy.c | ||
| mempool.c | ||
| migrate.c | ||
| mincore.c | ||
| mlock.c | ||
| mmap.c | ||
| mmzone.c | ||
| mprotect.c | ||
| mremap.c | ||
| msync.c | ||
| nommu.c | ||
| oom_kill.c | ||
| page_alloc.c | ||
| page_io.c | ||
| page-writeback.c | ||
| pdflush.c | ||
| prio_tree.c | ||
| readahead.c | ||
| rmap.c | ||
| shmem.c | ||
| slab.c | ||
| slob.c | ||
| sparse.c | ||
| swap_state.c | ||
| swap.c | ||
| swapfile.c | ||
| thrash.c | ||
| tiny-shmem.c | ||
| truncate.c | ||
| util.c | ||
| vmalloc.c | ||
| vmscan.c | ||