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mm: ksm: support hwpoison for ksm page

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hwpoison_user_mappings() is updated to support ksm pages, and add
collect_procs_ksm() to collect processes when the error hit an ksm page. 
The difference from collect_procs_anon() is that it also needs to traverse
the rmap-item list on the stable node of the ksm page.  At the same time,
add_to_kill_ksm() is added to handle ksm pages.  And
task_in_to_kill_list() is added to avoid duplicate addition of tsk to the
to_kill list.  This is because when scanning the list, if the pages that
make up the ksm page all come from the same process, they may be added
repeatedly.

Link: https://lkml.kernel.org/r/20230414021741.2597273-3-xialonglong1@huawei.com
Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Tested-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Longlong Xia 2023-04-14 10:17:41 +08:00 committed by Andrew Morton
parent 4f775086a6
commit 4248d0083e
4 changed files with 88 additions and 9 deletions
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11
include/linux/ksm.h
View File

@ -51,6 +51,10 @@ struct page *ksm_might_need_to_copy(struct page *page,
void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc);
void folio_migrate_ksm(struct folio *newfolio, struct folio *folio);
#ifdef CONFIG_MEMORY_FAILURE
void collect_procs_ksm(struct page *page, struct list_head *to_kill,
int force_early);
#endif
#else /* !CONFIG_KSM */
static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
@ -62,6 +66,13 @@ static inline void ksm_exit(struct mm_struct *mm)
{
}
#ifdef CONFIG_MEMORY_FAILURE
static inline void collect_procs_ksm(struct page *page,
struct list_head *to_kill, int force_early)
{
}
#endif
#ifdef CONFIG_MMU
static inline int ksm_madvise(struct vm_area_struct *vma, unsigned long start,
unsigned long end, int advice, unsigned long *vm_flags)

7
include/linux/mm.h
View File

@ -3604,6 +3604,7 @@ extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
bool *migratable_cleared);
void num_poisoned_pages_inc(unsigned long pfn);
void num_poisoned_pages_sub(unsigned long pfn, long i);
struct task_struct *task_early_kill(struct task_struct *tsk, int force_early);
#else
static inline void memory_failure_queue(unsigned long pfn, int flags)
{
@ -3624,6 +3625,12 @@ static inline void num_poisoned_pages_sub(unsigned long pfn, long i)
}
#endif
#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_KSM)
void add_to_kill_ksm(struct task_struct *tsk, struct page *p,
struct vm_area_struct *vma, struct list_head *to_kill,
unsigned long ksm_addr);
#endif
#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
extern void memblk_nr_poison_inc(unsigned long pfn);
extern void memblk_nr_poison_sub(unsigned long pfn, long i);

45
mm/ksm.c
View File

@ -2738,6 +2738,51 @@ void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc)
goto again;
}
#ifdef CONFIG_MEMORY_FAILURE
/*
* Collect processes when the error hit an ksm page.
*/
void collect_procs_ksm(struct page *page, struct list_head *to_kill,
int force_early)
{
struct ksm_stable_node *stable_node;
struct ksm_rmap_item *rmap_item;
struct folio *folio = page_folio(page);
struct vm_area_struct *vma;
struct task_struct *tsk;
stable_node = folio_stable_node(folio);
if (!stable_node)
return;
hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {
struct anon_vma *av = rmap_item->anon_vma;
anon_vma_lock_read(av);
read_lock(&tasklist_lock);
for_each_process(tsk) {
struct anon_vma_chain *vmac;
unsigned long addr;
struct task_struct *t =
task_early_kill(tsk, force_early);
if (!t)
continue;
anon_vma_interval_tree_foreach(vmac, &av->rb_root, 0,
ULONG_MAX)
{
vma = vmac->vma;
if (vma->vm_mm == t->mm) {
addr = rmap_item->address & PAGE_MASK;
add_to_kill_ksm(t, page, vma, to_kill,
addr);
}
}
}
read_unlock(&tasklist_lock);
anon_vma_unlock_read(av);
}
}
#endif
#ifdef CONFIG_MIGRATION
void folio_migrate_ksm(struct folio *newfolio, struct folio *folio)
{

34
mm/memory-failure.c
View File

@ -455,6 +455,27 @@ static void add_to_kill_anon_file(struct task_struct *tsk, struct page *p,
__add_to_kill(tsk, p, vma, to_kill, 0, FSDAX_INVALID_PGOFF);
}
#ifdef CONFIG_KSM
static bool task_in_to_kill_list(struct list_head *to_kill,
struct task_struct *tsk)
{
struct to_kill *tk, *next;
list_for_each_entry_safe(tk, next, to_kill, nd) {
if (tk->tsk == tsk)
return true;
}
return false;
}
void add_to_kill_ksm(struct task_struct *tsk, struct page *p,
struct vm_area_struct *vma, struct list_head *to_kill,
unsigned long ksm_addr)
{
if (!task_in_to_kill_list(to_kill, tsk))
__add_to_kill(tsk, p, vma, to_kill, ksm_addr, FSDAX_INVALID_PGOFF);
}
#endif
/*
* Kill the processes that have been collected earlier.
*
@ -534,8 +555,7 @@ static struct task_struct *find_early_kill_thread(struct task_struct *tsk)
* processes sharing the same error page,if the process is "early kill", the
* task_struct of the dedicated thread will also be returned.
*/
static struct task_struct *task_early_kill(struct task_struct *tsk,
int force_early)
struct task_struct *task_early_kill(struct task_struct *tsk, int force_early)
{
if (!tsk->mm)
return NULL;
@ -666,8 +686,9 @@ static void collect_procs(struct page *page, struct list_head *tokill,
{
if (!page->mapping)
return;
if (PageAnon(page))
if (unlikely(PageKsm(page)))
collect_procs_ksm(page, tokill, force_early);
else if (PageAnon(page))
collect_procs_anon(page, tokill, force_early);
else
collect_procs_file(page, tokill, force_early);
@ -1522,11 +1543,6 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
if (!page_mapped(hpage))
return true;
if (PageKsm(p)) {
pr_err("%#lx: can't handle KSM pages.\n", pfn);
return false;
}
if (PageSwapCache(p)) {
pr_err("%#lx: keeping poisoned page in swap cache\n", pfn);
ttu &= ~TTU_HWPOISON;