evie/android_kernel_oneplus_msm8998
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mm: ksm: avoid trageted reclaim of ksm pages

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Per Process Reclaim tries to avoid reclaiming of
shared pages by passing the target VMA. For anon and
file pages this works, but not for KSM. This is because
vma_address(page) will not return the intended value
resulting in crashes like this

[From 3.10 kernel]
kernel BUG at kernel/mm/rmap.c:534!
(vma_address+0x28/0x2c) from [<c01eff94>] (try_to_unmap_ksm+0x4c/0x170)
(try_to_unmap_ksm+0x4c/0x170) from [<c01e4834>] (try_to_unmap+0x34/0xa4)
(try_to_unmap+0x34/0xa4) from [<c01c8e64>] (shrink_page_list+0x3f0/0xa34)
(shrink_page_list+0x3f0/0xa34) from [<c01c9688>] (reclaim_pages_from_list)
(reclaim_pages_from_list+0xb0/0x100) from [<c0240ed0>] (reclaim_pte_range)
(reclaim_pte_range+0xf0/0x164) from [<c01e79a4>] (walk_page_range+0x1d0)
(walk_page_range+0x1d0/0x260) from [<c0241ccc>] (reclaim_task_anon+0xb0)
(reclaim_task_anon+0xb0/0x114) from [<c01f8d98>] (swap_fn+0x220/0x460)
(swap_fn+0x220/0x460) from [<c0133a38>] (process_one_work+0x294/0x430)
(process_one_work+0x294/0x430) from [<c0134720>] (worker_thread)
(worker_thread+0x224/0x358) from [<c01390d4>] (kthread+0xa0/0xac)
(kthread+0xa0/0xac) from [<c0105f38>] (ret_from_fork+0x14/0x3c)

CRs-Fixed: 984947
Change-Id: I5208fb68372f7af72868e39399bf545fb7b774f3
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
This commit is contained in:
Vinayak Menon 2016-02-25 19:10:19 +05:30 • committed by Kyle Yan
parent 1be1715f14
commit 7da300d6a3
1 changed files with 0 additions and 5 deletions
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5
mm/ksm.c
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@ -1985,11 +1985,6 @@ int rmap_walk_ksm(struct page *page, struct rmap_walk_control *rwc)
if (!stable_node)
return ret;
if (rwc->target_vma) {
unsigned long address = vma_address(page, rwc->target_vma);
ret = rwc->rmap_one(page, rwc->target_vma, address, rwc->arg);
goto out;
}
again:
hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {
struct anon_vma *anon_vma = rmap_item->anon_vma;