在 2021/10/15 3:32, Darrick J. Wong 写道:
On Fri, Sep 24, 2021 at 09:09:57PM +0800, Shiyang Ruan wrote:This function is called at the end of RMAP routine, i.e. filesystem recovery function, to collect and kill processes using a shared page of DAX file. The difference between mf_generic_kill_procs() is, it accepts file's mapping,offset instead of struct page. Because different file's mappings and offsets may share the same page in fsdax mode. So, it is called when filesystem RMAP results are found. Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> --- fs/dax.c | 10 ------ include/linux/dax.h | 9 +++++ include/linux/mm.h | 2 ++ mm/memory-failure.c | 83 ++++++++++++++++++++++++++++++++++++++++----- 4 files changed, 86 insertions(+), 18 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 509b65e60478..2536c105ec7f 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -852,16 +852,6 @@ static void *dax_insert_entry(struct xa_state *xas, return entry; }-static inline-unsigned long pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) -{ - unsigned long address; - - address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); - VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); - return address; -} - /* Walk all mappings of a given index of a file and writeprotect them */ static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index, unsigned long pfn) diff --git a/include/linux/dax.h b/include/linux/dax.h index 65411bee4312..3d90becbd160 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -258,6 +258,15 @@ static inline bool dax_mapping(struct address_space *mapping) { return mapping->host && IS_DAX(mapping->host); } +static inline unsigned long pgoff_address(pgoff_t pgoff, + struct vm_area_struct *vma) +{ + unsigned long address; + + address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); + return address; +}#ifdef CONFIG_DEV_DAX_HMEM_DEVICESvoid hmem_register_device(int target_nid, struct resource *r); diff --git a/include/linux/mm.h b/include/linux/mm.h index 73a52aba448f..d06af0051e53 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3114,6 +3114,8 @@ enum mf_flags { MF_MUST_KILL = 1 << 2, MF_SOFT_OFFLINE = 1 << 3, }; +extern int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, + size_t size, int flags); extern int memory_failure(unsigned long pfn, int flags); extern void memory_failure_queue(unsigned long pfn, int flags); extern void memory_failure_queue_kick(int cpu); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 85eab206b68f..a9d0d487d205 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -302,10 +302,9 @@ void shake_page(struct page *p) } EXPORT_SYMBOL_GPL(shake_page);-static unsigned long dev_pagemap_mapping_shift(struct page *page,+static unsigned long dev_pagemap_mapping_shift(unsigned long address, struct vm_area_struct *vma) { - unsigned long address = vma_address(page, vma); pgd_t *pgd; p4d_t *p4d; pud_t *pud; @@ -345,7 +344,7 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page, * Schedule a process for later kill. * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM. */ -static void add_to_kill(struct task_struct *tsk, struct page *p, +static void add_to_kill(struct task_struct *tsk, struct page *p, pgoff_t pgoff,Hm, so I guess you're passing the page and the pgoff now because page->index is meaningless for shared dax pages? Ok.
Yes, it is for that case.
struct vm_area_struct *vma, struct list_head *to_kill) { @@ -358,9 +357,15 @@ static void add_to_kill(struct task_struct *tsk, struct page *p, }tk->addr = page_address_in_vma(p, vma);- if (is_zone_device_page(p)) - tk->size_shift = dev_pagemap_mapping_shift(p, vma); - else + if (is_zone_device_page(p)) { + /* + * Since page->mapping is no more used for fsdax, we should + * calculate the address in a fsdax way. + */ + if (p->pgmap->type == MEMORY_DEVICE_FS_DAX) + tk->addr = pgoff_address(pgoff, vma); + tk->size_shift = dev_pagemap_mapping_shift(tk->addr, vma); + } else tk->size_shift = page_shift(compound_head(p));/*@@ -508,7 +513,7 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill, if (!page_mapped_in_vma(page, vma)) continue; if (vma->vm_mm == t->mm) - add_to_kill(t, page, vma, to_kill); + add_to_kill(t, page, 0, vma, to_kill); } } read_unlock(&tasklist_lock); @@ -544,7 +549,32 @@ static void collect_procs_file(struct page *page, struct list_head *to_kill, * to be informed of all such data corruptions. */ if (vma->vm_mm == t->mm) - add_to_kill(t, page, vma, to_kill); + add_to_kill(t, page, 0, vma, to_kill); + } + } + read_unlock(&tasklist_lock); + i_mmap_unlock_read(mapping); +} + +/* + * Collect processes when the error hit a fsdax page. + */ +static void collect_procs_fsdax(struct page *page, struct address_space *mapping, + pgoff_t pgoff, struct list_head *to_kill) +{ + struct vm_area_struct *vma; + struct task_struct *tsk; + + i_mmap_lock_read(mapping); + read_lock(&tasklist_lock); + for_each_process(tsk) { + struct task_struct *t = task_early_kill(tsk, true); + + if (!t) + continue; + vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { + if (vma->vm_mm == t->mm) + add_to_kill(t, page, pgoff, vma, to_kill); } } read_unlock(&tasklist_lock); @@ -1503,6 +1533,43 @@ static int mf_generic_kill_procs(unsigned long long pfn, int flags, return 0; }+/**+ * mf_dax_kill_procs - Collect and kill processes who are using this file range + * @mapping: the file in use + * @index: start offset of the range + * @size: length of the rangeIt feels odd that one argument is in units of pgoff_t but the other is in bytes.
The index is page aligned but @size may not be. I will explain it in detail in the comments.
+ * @flags: memory failure flags + */ +int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, + size_t size, int flags) +{ + LIST_HEAD(to_kill); + dax_entry_t cookie; + struct page *page; + size_t end = (index << PAGE_SHIFT) + size; + + flags |= MF_ACTION_REQUIRED | MF_MUST_KILL;Hm. What flags will we be passing to the xfs_dax_notify_failure_fn? Does XFS itself have to care about what's in the flags values, or is it really just a magic cookie to be passed from the mm layer into the fs and back to mf_dax_kill_procs?
Just to pass the flag from mm layer to mf_dax_kill_procs(). No one inside this RMAP progress will care about or change it. As you mentioned in the next patch, I think this should be named with a "mf_" prefix to make it easier to understand.
-- Thanks, Ruan.
--D+ + for (; (index << PAGE_SHIFT) < end; index++) { + page = NULL; + cookie = dax_lock_mapping_entry(mapping, index, &page); + if (!cookie) + return -EBUSY; + if (!page) + goto unlock; + + SetPageHWPoison(page); + + collect_procs_fsdax(page, mapping, index, &to_kill); + unmap_and_kill(&to_kill, page_to_pfn(page), mapping, + index, flags); +unlock: + dax_unlock_mapping_entry(mapping, index, cookie); + } + return 0; +} +EXPORT_SYMBOL_GPL(mf_dax_kill_procs); + static int memory_failure_hugetlb(unsigned long pfn, int flags) { struct page *p = pfn_to_page(pfn); -- 2.33.0
