From ae1139ece126b8eb6d0770094fbac43ea928d9d9 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 13 Jul 2018 21:50:11 -0700 Subject: mm, memory_failure: Collect mapping size in collect_procs() In preparation for supporting memory_failure() for dax mappings, teach collect_procs() to also determine the mapping size. Unlike typical mappings the dax mapping size is determined by walking page-table entries rather than using the compound-page accounting for THP pages. Acked-by: Naoya Horiguchi Signed-off-by: Dan Williams Signed-off-by: Dave Jiang --- mm/memory-failure.c | 81 ++++++++++++++++++++++++++--------------------------- 1 file changed, 40 insertions(+), 41 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 988f977db3d2..8a81680d00dd 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -173,23 +173,52 @@ int hwpoison_filter(struct page *p) EXPORT_SYMBOL_GPL(hwpoison_filter); +/* + * Kill all processes that have a poisoned page mapped and then isolate + * the page. + * + * General strategy: + * Find all processes having the page mapped and kill them. + * But we keep a page reference around so that the page is not + * actually freed yet. + * Then stash the page away + * + * There's no convenient way to get back to mapped processes + * from the VMAs. So do a brute-force search over all + * running processes. + * + * Remember that machine checks are not common (or rather + * if they are common you have other problems), so this shouldn't + * be a performance issue. + * + * Also there are some races possible while we get from the + * error detection to actually handle it. + */ + +struct to_kill { + struct list_head nd; + struct task_struct *tsk; + unsigned long addr; + short size_shift; + char addr_valid; +}; + /* * Send all the processes who have the page mapped a signal. * ``action optional'' if they are not immediately affected by the error * ``action required'' if error happened in current execution context */ -static int kill_proc(struct task_struct *t, unsigned long addr, - unsigned long pfn, struct page *page, int flags) +static int kill_proc(struct to_kill *tk, unsigned long pfn, int flags) { - short addr_lsb; + struct task_struct *t = tk->tsk; + short addr_lsb = tk->size_shift; int ret; pr_err("Memory failure: %#lx: Killing %s:%d due to hardware memory corruption\n", pfn, t->comm, t->pid); - addr_lsb = compound_order(compound_head(page)) + PAGE_SHIFT; if ((flags & MF_ACTION_REQUIRED) && t->mm == current->mm) { - ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)addr, + ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)tk->addr, addr_lsb, current); } else { /* @@ -198,7 +227,7 @@ static int kill_proc(struct task_struct *t, unsigned long addr, * This could cause a loop when the user sets SIGBUS * to SIG_IGN, but hopefully no one will do that? */ - ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)addr, + ret = send_sig_mceerr(BUS_MCEERR_AO, (void __user *)tk->addr, addr_lsb, t); /* synchronous? */ } if (ret < 0) @@ -234,35 +263,6 @@ void shake_page(struct page *p, int access) } EXPORT_SYMBOL_GPL(shake_page); -/* - * Kill all processes that have a poisoned page mapped and then isolate - * the page. - * - * General strategy: - * Find all processes having the page mapped and kill them. - * But we keep a page reference around so that the page is not - * actually freed yet. - * Then stash the page away - * - * There's no convenient way to get back to mapped processes - * from the VMAs. So do a brute-force search over all - * running processes. - * - * Remember that machine checks are not common (or rather - * if they are common you have other problems), so this shouldn't - * be a performance issue. - * - * Also there are some races possible while we get from the - * error detection to actually handle it. - */ - -struct to_kill { - struct list_head nd; - struct task_struct *tsk; - unsigned long addr; - char addr_valid; -}; - /* * Failure handling: if we can't find or can't kill a process there's * not much we can do. We just print a message and ignore otherwise. @@ -292,6 +292,7 @@ static void add_to_kill(struct task_struct *tsk, struct page *p, } tk->addr = page_address_in_vma(p, vma); tk->addr_valid = 1; + tk->size_shift = compound_order(compound_head(p)) + PAGE_SHIFT; /* * In theory we don't have to kill when the page was @@ -317,9 +318,8 @@ static void add_to_kill(struct task_struct *tsk, struct page *p, * Also when FAIL is set do a force kill because something went * wrong earlier. */ -static void kill_procs(struct list_head *to_kill, int forcekill, - bool fail, struct page *page, unsigned long pfn, - int flags) +static void kill_procs(struct list_head *to_kill, int forcekill, bool fail, + unsigned long pfn, int flags) { struct to_kill *tk, *next; @@ -342,8 +342,7 @@ static void kill_procs(struct list_head *to_kill, int forcekill, * check for that, but we need to tell the * process anyways. */ - else if (kill_proc(tk->tsk, tk->addr, - pfn, page, flags) < 0) + else if (kill_proc(tk, pfn, flags) < 0) pr_err("Memory failure: %#lx: Cannot send advisory machine check signal to %s:%d\n", pfn, tk->tsk->comm, tk->tsk->pid); } @@ -1012,7 +1011,7 @@ static bool hwpoison_user_mappings(struct page *p, unsigned long pfn, * any accesses to the poisoned memory. */ forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL); - kill_procs(&tokill, forcekill, !unmap_success, p, pfn, flags); + kill_procs(&tokill, forcekill, !unmap_success, pfn, flags); return unmap_success; } -- cgit v1.2.3-59-g8ed1b