| Message ID | 20210604011844.1756145-5-ruansy.fnst@fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fsdax: introduce fs query to support reflink | expand |
[ drop old nvdimm list, add the new one ] On Thu, Jun 3, 2021 at 6:19 PM Shiyang Ruan <ruansy.fnst@fujitsu.com> wrote: > > The current memory_failure_dev_pagemap() can only handle single-mapped > dax page for fsdax mode. The dax page could be mapped by multiple files > and offsets if we let reflink feature & fsdax mode work together. So, > we refactor current implementation to support handle memory failure on > each file and offset. I don't understand this organization, perhaps because this patch introduces mf_dax_kill_procs() without a user. However, my expectation is that memory_failure() is mostly untouched save for an early check via pgmap->notify_memory_failure(). If pgmap->notify_memory_failure() indicates that the memory failure was handled by the pgmap->owner / dax_dev holder stack, then the typical memory failure path is short-circuited. Otherwise, for non-reflink filesystems where page->mapping() is valid the legacy / existing memory_failure() operates as it does currently. If reflink capable filesystems want to share a common implementation to map pfns to files they can, but I don't think that common code belongs in mm/memory-failure.c. > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > --- > fs/dax.c | 21 ++++++++ > include/linux/dax.h | 1 + > include/linux/mm.h | 9 ++++ > mm/memory-failure.c | 114 ++++++++++++++++++++++++++++---------------- > 4 files changed, 105 insertions(+), 40 deletions(-) > > diff --git a/fs/dax.c b/fs/dax.c > index 62352cbcf0f4..58faca85455a 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -389,6 +389,27 @@ static struct page *dax_busy_page(void *entry) > return NULL; > } > > +/* > + * dax_load_pfn - Load pfn of the DAX entry corresponding to a page > + * @mapping: The file whose entry we want to load > + * @index: The offset where the DAX entry located in > + * > + * Return: pfn of the DAX entry > + */ > +unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index) > +{ > + XA_STATE(xas, &mapping->i_pages, index); > + void *entry; > + unsigned long pfn; > + > + xas_lock_irq(&xas); > + entry = xas_load(&xas); > + pfn = dax_to_pfn(entry); > + xas_unlock_irq(&xas); This looks racy, what happened to the locking afforded by dax_lock_page()? > + > + return pfn; > +} > + > /* > * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page > * @page: The page whose entry we want to lock > diff --git a/include/linux/dax.h b/include/linux/dax.h > index 1ce343a960ab..6e758daa5004 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -158,6 +158,7 @@ int dax_writeback_mapping_range(struct address_space *mapping, > > struct page *dax_layout_busy_page(struct address_space *mapping); > struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); > +unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index); > dax_entry_t dax_lock_page(struct page *page); > void dax_unlock_page(struct page *page, dax_entry_t cookie); > #else > diff --git a/include/linux/mm.h b/include/linux/mm.h > index c274f75efcf9..2b7527e93c77 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1187,6 +1187,14 @@ static inline bool is_device_private_page(const struct page *page) > page->pgmap->type == MEMORY_DEVICE_PRIVATE; > } > > +static inline bool is_device_fsdax_page(const struct page *page) > +{ > + return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) && > + IS_ENABLED(CONFIG_FS_DAX) && > + is_zone_device_page(page) && > + page->pgmap->type == MEMORY_DEVICE_FS_DAX; Why is this necessary? The dax_dev holder is the one that knows the nature of the pfn. The common memory_failure() code should not care about fsdax vs devdax. > +} > + > static inline bool is_pci_p2pdma_page(const struct page *page) > { > return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) && > @@ -3078,6 +3086,7 @@ enum mf_flags { > MF_MUST_KILL = 1 << 2, > MF_SOFT_OFFLINE = 1 << 3, > }; > +int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, 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 85ad98c00fd9..4377e727d478 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -56,6 +56,7 @@ > #include <linux/kfifo.h> > #include <linux/ratelimit.h> > #include <linux/page-isolation.h> > +#include <linux/dax.h> > #include "internal.h" > #include "ras/ras_event.h" > > @@ -120,6 +121,13 @@ static int hwpoison_filter_dev(struct page *p) > if (PageSlab(p)) > return -EINVAL; > > + if (pfn_valid(page_to_pfn(p))) { > + if (is_device_fsdax_page(p)) This is racy unless the page is pinned. Also, not clear why this is needed? > + return 0; > + else > + return -EINVAL; > + } > + > mapping = page_mapping(p); > if (mapping == NULL || mapping->host == NULL) > return -EINVAL; > @@ -290,10 +298,9 @@ void shake_page(struct page *p, int access) > } > EXPORT_SYMBOL_GPL(shake_page); > > -static unsigned long dev_pagemap_mapping_shift(struct page *page, > - struct vm_area_struct *vma) > +static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma, > + unsigned long address) > { > - unsigned long address = vma_address(page, vma); > pgd_t *pgd; > p4d_t *p4d; > pud_t *pud; > @@ -333,9 +340,8 @@ 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, > - struct vm_area_struct *vma, > - struct list_head *to_kill) > +static void add_to_kill(struct task_struct *tsk, struct page *p, pgoff_t pgoff, > + struct vm_area_struct *vma, struct list_head *to_kill) > { > struct to_kill *tk; > > @@ -346,9 +352,12 @@ 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)) { > + if (is_device_fsdax_page(p)) > + tk->addr = vma->vm_start + > + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); > + tk->size_shift = dev_pagemap_mapping_shift(vma, tk->addr); What was wrong with the original code? > + } else > tk->size_shift = page_shift(compound_head(p)); > > /* > @@ -496,7 +505,7 @@ 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); > @@ -506,24 +515,19 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill, > /* > * Collect processes when the error hit a file mapped page. > */ > -static void collect_procs_file(struct page *page, struct list_head *to_kill, > - int force_early) > +static void collect_procs_file(struct page *page, struct address_space *mapping, > + pgoff_t pgoff, struct list_head *to_kill, int force_early) > { collect_procs() and kill_procs() are the only core memory_failure() helpers I expect would be exported for a fileystem dax_dev holder to call when it is trying to cleanup a memory_failure() on a reflink'd mapping. > struct vm_area_struct *vma; > struct task_struct *tsk; > - struct address_space *mapping = page->mapping; > - pgoff_t pgoff; > > i_mmap_lock_read(mapping); > read_lock(&tasklist_lock); > - pgoff = page_to_pgoff(page); > for_each_process(tsk) { > struct task_struct *t = task_early_kill(tsk, force_early); > - > if (!t) > continue; > - vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, > - pgoff) { > + vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { > /* > * Send early kill signal to tasks where a vma covers > * the page but the corrupted page is not necessarily > @@ -532,7 +536,7 @@ 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, pgoff, vma, to_kill); > } > } > read_unlock(&tasklist_lock); > @@ -551,7 +555,8 @@ static void collect_procs(struct page *page, struct list_head *tokill, > if (PageAnon(page)) > collect_procs_anon(page, tokill, force_early); > else > - collect_procs_file(page, tokill, force_early); > + collect_procs_file(page, page_mapping(page), page_to_pgoff(page), > + tokill, force_early); > } > > static const char *action_name[] = { > @@ -1218,6 +1223,51 @@ static int try_to_split_thp_page(struct page *page, const char *msg) > return 0; > } > > +static void unmap_and_kill(struct list_head *to_kill, unsigned long pfn, > + struct address_space *mapping, pgoff_t index, int flags) > +{ > + struct to_kill *tk; > + unsigned long size = 0; > + loff_t start; > + > + list_for_each_entry(tk, to_kill, nd) > + if (tk->size_shift) > + size = max(size, 1UL << tk->size_shift); > + if (size) { > + /* > + * Unmap the largest mapping to avoid breaking up > + * device-dax mappings which are constant size. The > + * actual size of the mapping being torn down is > + * communicated in siginfo, see kill_proc() > + */ > + start = (index << PAGE_SHIFT) & ~(size - 1); > + unmap_mapping_range(mapping, start, size, 0); > + } > + > + kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); > +} > + > +int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, int flags) > +{ > + LIST_HEAD(to_kill); > + /* load the pfn of the dax mapping file */ > + unsigned long pfn = dax_load_pfn(mapping, index); > + > + /* > + * Unlike System-RAM there is no possibility to swap in a > + * different physical page at a given virtual address, so all > + * userspace consumption of ZONE_DEVICE memory necessitates > + * SIGBUS (i.e. MF_MUST_KILL) > + */ > + flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; > + collect_procs_file(pfn_to_page(pfn), mapping, index, &to_kill, > + flags & MF_ACTION_REQUIRED); > + > + unmap_and_kill(&to_kill, pfn, mapping, index, flags); > + 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); > @@ -1298,12 +1348,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > struct dev_pagemap *pgmap) > { > struct page *page = pfn_to_page(pfn); > - const bool unmap_success = true; > - unsigned long size = 0; > - struct to_kill *tk; > - LIST_HEAD(tokill); > + LIST_HEAD(to_kill); > int rc = -EBUSY; > - loff_t start; > dax_entry_t cookie; > > if (flags & MF_COUNT_INCREASED) > @@ -1355,22 +1401,10 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > * SIGBUS (i.e. MF_MUST_KILL) > */ > flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; > - collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED); > + collect_procs_file(page, page->mapping, page->index, &to_kill, > + flags & MF_ACTION_REQUIRED); > > - list_for_each_entry(tk, &tokill, nd) > - if (tk->size_shift) > - size = max(size, 1UL << tk->size_shift); > - if (size) { > - /* > - * Unmap the largest mapping to avoid breaking up > - * device-dax mappings which are constant size. The > - * actual size of the mapping being torn down is > - * communicated in siginfo, see kill_proc() > - */ > - start = (page->index << PAGE_SHIFT) & ~(size - 1); > - unmap_mapping_range(page->mapping, start, size, 0); > - } > - kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags); > + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); There's just too much change in this patch and not enough justification of what is being refactored and why.
> -----Original Message----- > From: Dan Williams <dan.j.williams@intel.com> > Subject: Re: [PATCH v4 04/10] mm, fsdax: Refactor memory-failure handler for > dax mapping > > [ drop old nvdimm list, add the new one ] > > On Thu, Jun 3, 2021 at 6:19 PM Shiyang Ruan <ruansy.fnst@fujitsu.com> wrote: > > > > The current memory_failure_dev_pagemap() can only handle single-mapped > > dax page for fsdax mode. The dax page could be mapped by multiple > > files and offsets if we let reflink feature & fsdax mode work > > together. So, we refactor current implementation to support handle > > memory failure on each file and offset. > > I don't understand this organization, perhaps because this patch introduces > mf_dax_kill_procs() without a user. Yes, I think I made it a mess... I should reorganize this whole patchset. The mf_dax_kill_procs() is used by xfs in patch 9. I was mean to refactor these code for the next patches usage. > However, my expectation is that > memory_failure() is mostly untouched save for an early check via > pgmap->notify_memory_failure(). If pgmap->notify_memory_failure() indicates > that the memory failure was handled by the pgmap->owner / dax_dev holder > stack, then the typical memory failure path is short-circuited. Otherwise, for > non-reflink filesystems where > page->mapping() is valid the legacy / existing memory_failure() > operates as it does currently. You can find this logic in patch 5. When it comes to memory-failure() and memory_failure_dev_pagemap(), after some check, it will try to call pgmap->ops->memory_failure(). If this interface is implemented, for example pgmap is pmem device, it will call the dax_dev holder stack. And finally, it comes to mf_dax_kill_procs(). However, if something wrong happens in this stack, such as feature not support or interface not implemented, it will roll back to normal memory-failure hanlder which is refactored as mf_generic_kill_porcs(). So, I think we are in agreement on this. Let me reorganize these code. > If reflink capable filesystems want to share a > common implementation to map pfns to files they can, but I don't think that > common code belongs in mm/memory-failure.c. > > > > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > > --- > > fs/dax.c | 21 ++++++++ > > include/linux/dax.h | 1 + > > include/linux/mm.h | 9 ++++ > > mm/memory-failure.c | 114 > > ++++++++++++++++++++++++++++---------------- > > 4 files changed, 105 insertions(+), 40 deletions(-) > > > > diff --git a/fs/dax.c b/fs/dax.c > > index 62352cbcf0f4..58faca85455a 100644 > > --- a/fs/dax.c > > +++ b/fs/dax.c > > @@ -389,6 +389,27 @@ static struct page *dax_busy_page(void *entry) > > return NULL; > > } > > > > +/* > > + * dax_load_pfn - Load pfn of the DAX entry corresponding to a page > > + * @mapping: The file whose entry we want to load > > + * @index: The offset where the DAX entry located in > > + * > > + * Return: pfn of the DAX entry > > + */ > > +unsigned long dax_load_pfn(struct address_space *mapping, unsigned > > +long index) { > > + XA_STATE(xas, &mapping->i_pages, index); > > + void *entry; > > + unsigned long pfn; > > + > > + xas_lock_irq(&xas); > > + entry = xas_load(&xas); > > + pfn = dax_to_pfn(entry); > > + xas_unlock_irq(&xas); > > This looks racy, what happened to the locking afforded by dax_lock_page()? > > > + > > + return pfn; > > +} > > + > > /* > > * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page > > * @page: The page whose entry we want to lock diff --git > > a/include/linux/dax.h b/include/linux/dax.h index > > 1ce343a960ab..6e758daa5004 100644 > > --- a/include/linux/dax.h > > +++ b/include/linux/dax.h > > @@ -158,6 +158,7 @@ int dax_writeback_mapping_range(struct > > address_space *mapping, > > > > struct page *dax_layout_busy_page(struct address_space *mapping); > > struct page *dax_layout_busy_page_range(struct address_space *mapping, > > loff_t start, loff_t end); > > +unsigned long dax_load_pfn(struct address_space *mapping, unsigned > > +long index); > > dax_entry_t dax_lock_page(struct page *page); void > > dax_unlock_page(struct page *page, dax_entry_t cookie); #else diff > > --git a/include/linux/mm.h b/include/linux/mm.h index > > c274f75efcf9..2b7527e93c77 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -1187,6 +1187,14 @@ static inline bool is_device_private_page(const > struct page *page) > > page->pgmap->type == MEMORY_DEVICE_PRIVATE; } > > > > +static inline bool is_device_fsdax_page(const struct page *page) { > > + return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) && > > + IS_ENABLED(CONFIG_FS_DAX) && > > + is_zone_device_page(page) && > > + page->pgmap->type == MEMORY_DEVICE_FS_DAX; > > Why is this necessary? The dax_dev holder is the one that knows the nature of > the pfn. The common memory_failure() code should not care about fsdax vs > devdax. add_to_kill() in collect_procs() needs this. Please see explanation at below. > > > +} > > + > > static inline bool is_pci_p2pdma_page(const struct page *page) { > > return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) && @@ > -3078,6 > > +3086,7 @@ enum mf_flags { > > MF_MUST_KILL = 1 << 2, > > MF_SOFT_OFFLINE = 1 << 3, > > }; > > +int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, > > +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 85ad98c00fd9..4377e727d478 100644 > > --- a/mm/memory-failure.c > > +++ b/mm/memory-failure.c > > @@ -56,6 +56,7 @@ > > #include <linux/kfifo.h> > > #include <linux/ratelimit.h> > > #include <linux/page-isolation.h> > > +#include <linux/dax.h> > > #include "internal.h" > > #include "ras/ras_event.h" > > > > @@ -120,6 +121,13 @@ static int hwpoison_filter_dev(struct page *p) > > if (PageSlab(p)) > > return -EINVAL; > > > > + if (pfn_valid(page_to_pfn(p))) { > > + if (is_device_fsdax_page(p)) > > This is racy unless the page is pinned. Also, not clear why this is needed? > > > + return 0; > > + else > > + return -EINVAL; > > + } > > + > > mapping = page_mapping(p); > > if (mapping == NULL || mapping->host == NULL) > > return -EINVAL; > > @@ -290,10 +298,9 @@ void shake_page(struct page *p, int access) } > > EXPORT_SYMBOL_GPL(shake_page); > > > > -static unsigned long dev_pagemap_mapping_shift(struct page *page, > > - struct vm_area_struct *vma) > > +static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct > *vma, > > + unsigned long > address) > > { > > - unsigned long address = vma_address(page, vma); > > pgd_t *pgd; > > p4d_t *p4d; > > pud_t *pud; > > @@ -333,9 +340,8 @@ 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, > > - struct vm_area_struct *vma, > > - struct list_head *to_kill) > > +static void add_to_kill(struct task_struct *tsk, struct page *p, pgoff_t pgoff, > > + struct vm_area_struct *vma, struct list_head > > +*to_kill) > > { > > struct to_kill *tk; > > > > @@ -346,9 +352,12 @@ 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)) { > > + if (is_device_fsdax_page(p)) > > + tk->addr = vma->vm_start + > > + ((pgoff - vma->vm_pgoff) << > PAGE_SHIFT); > > + tk->size_shift = dev_pagemap_mapping_shift(vma, > > + tk->addr); > > What was wrong with the original code? Here is the explanation: For normal page, it associate file's mapping and offset to page->mapping, page->index for rmap tracking. But for fsdax, in order to support reflink, we no longer use this mechanism, using dax_device holder stack instead. Thus, this dax page->mapping is NULL. As a result, we need is_device_fsdax_page(p) to distinguish if a page is a fsdax page and calculate this tk->addr manually. > > > + } else > > tk->size_shift = page_shift(compound_head(p)); > > > > /* > > @@ -496,7 +505,7 @@ 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); > > @@ -506,24 +515,19 @@ static void collect_procs_anon(struct page > > *page, struct list_head *to_kill, > > /* > > * Collect processes when the error hit a file mapped page. > > */ > > -static void collect_procs_file(struct page *page, struct list_head *to_kill, > > - int force_early) > > +static void collect_procs_file(struct page *page, struct address_space > *mapping, > > + pgoff_t pgoff, struct list_head *to_kill, int > > +force_early) > > { > > collect_procs() and kill_procs() are the only core memory_failure() helpers I > expect would be exported for a fileystem dax_dev holder to call when it is trying > to cleanup a memory_failure() on a reflink'd mapping. Yes, they are the core we need. But there are some small different when dealing with normal page and dax page. So, I factor these two core functions into two helpers. One is mf_generic_kill_procs() for normal page. Another is mf_dax_kill_procs() for dax page. > > > struct vm_area_struct *vma; > > struct task_struct *tsk; > > - struct address_space *mapping = page->mapping; > > - pgoff_t pgoff; > > > > i_mmap_lock_read(mapping); > > read_lock(&tasklist_lock); > > - pgoff = page_to_pgoff(page); > > for_each_process(tsk) { > > struct task_struct *t = task_early_kill(tsk, > > force_early); > > - > > if (!t) > > continue; > > - vma_interval_tree_foreach(vma, &mapping->i_mmap, > pgoff, > > - pgoff) { > > + vma_interval_tree_foreach(vma, &mapping->i_mmap, > > + pgoff, pgoff) { > > /* > > * Send early kill signal to tasks where a vma > covers > > * the page but the corrupted page is not > > necessarily @@ -532,7 +536,7 @@ 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, pgoff, vma, > > + to_kill); > > } > > } > > read_unlock(&tasklist_lock); > > @@ -551,7 +555,8 @@ static void collect_procs(struct page *page, struct > list_head *tokill, > > if (PageAnon(page)) > > collect_procs_anon(page, tokill, force_early); > > else > > - collect_procs_file(page, tokill, force_early); > > + collect_procs_file(page, page_mapping(page), > page_to_pgoff(page), > > + tokill, force_early); > > } > > > > static const char *action_name[] = { > > @@ -1218,6 +1223,51 @@ static int try_to_split_thp_page(struct page *page, > const char *msg) > > return 0; > > } > > > > +static void unmap_and_kill(struct list_head *to_kill, unsigned long pfn, > > + struct address_space *mapping, pgoff_t index, int > > +flags) { > > + struct to_kill *tk; > > + unsigned long size = 0; > > + loff_t start; > > + > > + list_for_each_entry(tk, to_kill, nd) > > + if (tk->size_shift) > > + size = max(size, 1UL << tk->size_shift); > > + if (size) { > > + /* > > + * Unmap the largest mapping to avoid breaking up > > + * device-dax mappings which are constant size. The > > + * actual size of the mapping being torn down is > > + * communicated in siginfo, see kill_proc() > > + */ > > + start = (index << PAGE_SHIFT) & ~(size - 1); > > + unmap_mapping_range(mapping, start, size, 0); > > + } > > + > > + kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); > > +} > > + > > +int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, > > +int flags) { > > + LIST_HEAD(to_kill); > > + /* load the pfn of the dax mapping file */ > > + unsigned long pfn = dax_load_pfn(mapping, index); > > + > > + /* > > + * Unlike System-RAM there is no possibility to swap in a > > + * different physical page at a given virtual address, so all > > + * userspace consumption of ZONE_DEVICE memory necessitates > > + * SIGBUS (i.e. MF_MUST_KILL) > > + */ > > + flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; > > + collect_procs_file(pfn_to_page(pfn), mapping, index, &to_kill, > > + flags & MF_ACTION_REQUIRED); > > + > > + unmap_and_kill(&to_kill, pfn, mapping, index, flags); > > + 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); @@ -1298,12 +1348,8 @@ > > static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > > struct dev_pagemap *pgmap) { > > struct page *page = pfn_to_page(pfn); > > - const bool unmap_success = true; > > - unsigned long size = 0; > > - struct to_kill *tk; > > - LIST_HEAD(tokill); > > + LIST_HEAD(to_kill); > > int rc = -EBUSY; > > - loff_t start; > > dax_entry_t cookie; > > > > if (flags & MF_COUNT_INCREASED) @@ -1355,22 +1401,10 @@ > static > > int memory_failure_dev_pagemap(unsigned long pfn, int flags, > > * SIGBUS (i.e. MF_MUST_KILL) > > */ > > flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; > > - collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED); > > + collect_procs_file(page, page->mapping, page->index, &to_kill, > > + flags & MF_ACTION_REQUIRED); > > > > - list_for_each_entry(tk, &tokill, nd) > > - if (tk->size_shift) > > - size = max(size, 1UL << tk->size_shift); > > - if (size) { > > - /* > > - * Unmap the largest mapping to avoid breaking up > > - * device-dax mappings which are constant size. The > > - * actual size of the mapping being torn down is > > - * communicated in siginfo, see kill_proc() > > - */ > > - start = (page->index << PAGE_SHIFT) & ~(size - 1); > > - unmap_mapping_range(page->mapping, start, size, 0); > > - } > > - kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, > flags); > > + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, > > + flags); > > There's just too much change in this patch and not enough justification of what > is being refactored and why. Sorry again for the mess... -- Thanks, Ruan.
diff --git a/fs/dax.c b/fs/dax.c index 62352cbcf0f4..58faca85455a 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -389,6 +389,27 @@ static struct page *dax_busy_page(void *entry) return NULL; } +/* + * dax_load_pfn - Load pfn of the DAX entry corresponding to a page + * @mapping: The file whose entry we want to load + * @index: The offset where the DAX entry located in + * + * Return: pfn of the DAX entry + */ +unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index) +{ + XA_STATE(xas, &mapping->i_pages, index); + void *entry; + unsigned long pfn; + + xas_lock_irq(&xas); + entry = xas_load(&xas); + pfn = dax_to_pfn(entry); + xas_unlock_irq(&xas); + + return pfn; +} + /* * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page * @page: The page whose entry we want to lock diff --git a/include/linux/dax.h b/include/linux/dax.h index 1ce343a960ab..6e758daa5004 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -158,6 +158,7 @@ int dax_writeback_mapping_range(struct address_space *mapping, struct page *dax_layout_busy_page(struct address_space *mapping); struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end); +unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index); dax_entry_t dax_lock_page(struct page *page); void dax_unlock_page(struct page *page, dax_entry_t cookie); #else diff --git a/include/linux/mm.h b/include/linux/mm.h index c274f75efcf9..2b7527e93c77 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1187,6 +1187,14 @@ static inline bool is_device_private_page(const struct page *page) page->pgmap->type == MEMORY_DEVICE_PRIVATE; } +static inline bool is_device_fsdax_page(const struct page *page) +{ + return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) && + IS_ENABLED(CONFIG_FS_DAX) && + is_zone_device_page(page) && + page->pgmap->type == MEMORY_DEVICE_FS_DAX; +} + static inline bool is_pci_p2pdma_page(const struct page *page) { return IS_ENABLED(CONFIG_DEV_PAGEMAP_OPS) && @@ -3078,6 +3086,7 @@ enum mf_flags { MF_MUST_KILL = 1 << 2, MF_SOFT_OFFLINE = 1 << 3, }; +int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, 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 85ad98c00fd9..4377e727d478 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -56,6 +56,7 @@ #include <linux/kfifo.h> #include <linux/ratelimit.h> #include <linux/page-isolation.h> +#include <linux/dax.h> #include "internal.h" #include "ras/ras_event.h" @@ -120,6 +121,13 @@ static int hwpoison_filter_dev(struct page *p) if (PageSlab(p)) return -EINVAL; + if (pfn_valid(page_to_pfn(p))) { + if (is_device_fsdax_page(p)) + return 0; + else + return -EINVAL; + } + mapping = page_mapping(p); if (mapping == NULL || mapping->host == NULL) return -EINVAL; @@ -290,10 +298,9 @@ void shake_page(struct page *p, int access) } EXPORT_SYMBOL_GPL(shake_page); -static unsigned long dev_pagemap_mapping_shift(struct page *page, - struct vm_area_struct *vma) +static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma, + unsigned long address) { - unsigned long address = vma_address(page, vma); pgd_t *pgd; p4d_t *p4d; pud_t *pud; @@ -333,9 +340,8 @@ 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, - struct vm_area_struct *vma, - struct list_head *to_kill) +static void add_to_kill(struct task_struct *tsk, struct page *p, pgoff_t pgoff, + struct vm_area_struct *vma, struct list_head *to_kill) { struct to_kill *tk; @@ -346,9 +352,12 @@ 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)) { + if (is_device_fsdax_page(p)) + tk->addr = vma->vm_start + + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + tk->size_shift = dev_pagemap_mapping_shift(vma, tk->addr); + } else tk->size_shift = page_shift(compound_head(p)); /* @@ -496,7 +505,7 @@ 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); @@ -506,24 +515,19 @@ static void collect_procs_anon(struct page *page, struct list_head *to_kill, /* * Collect processes when the error hit a file mapped page. */ -static void collect_procs_file(struct page *page, struct list_head *to_kill, - int force_early) +static void collect_procs_file(struct page *page, struct address_space *mapping, + pgoff_t pgoff, struct list_head *to_kill, int force_early) { struct vm_area_struct *vma; struct task_struct *tsk; - struct address_space *mapping = page->mapping; - pgoff_t pgoff; i_mmap_lock_read(mapping); read_lock(&tasklist_lock); - pgoff = page_to_pgoff(page); for_each_process(tsk) { struct task_struct *t = task_early_kill(tsk, force_early); - if (!t) continue; - vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, - pgoff) { + vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { /* * Send early kill signal to tasks where a vma covers * the page but the corrupted page is not necessarily @@ -532,7 +536,7 @@ 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, pgoff, vma, to_kill); } } read_unlock(&tasklist_lock); @@ -551,7 +555,8 @@ static void collect_procs(struct page *page, struct list_head *tokill, if (PageAnon(page)) collect_procs_anon(page, tokill, force_early); else - collect_procs_file(page, tokill, force_early); + collect_procs_file(page, page_mapping(page), page_to_pgoff(page), + tokill, force_early); } static const char *action_name[] = { @@ -1218,6 +1223,51 @@ static int try_to_split_thp_page(struct page *page, const char *msg) return 0; } +static void unmap_and_kill(struct list_head *to_kill, unsigned long pfn, + struct address_space *mapping, pgoff_t index, int flags) +{ + struct to_kill *tk; + unsigned long size = 0; + loff_t start; + + list_for_each_entry(tk, to_kill, nd) + if (tk->size_shift) + size = max(size, 1UL << tk->size_shift); + if (size) { + /* + * Unmap the largest mapping to avoid breaking up + * device-dax mappings which are constant size. The + * actual size of the mapping being torn down is + * communicated in siginfo, see kill_proc() + */ + start = (index << PAGE_SHIFT) & ~(size - 1); + unmap_mapping_range(mapping, start, size, 0); + } + + kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); +} + +int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, int flags) +{ + LIST_HEAD(to_kill); + /* load the pfn of the dax mapping file */ + unsigned long pfn = dax_load_pfn(mapping, index); + + /* + * Unlike System-RAM there is no possibility to swap in a + * different physical page at a given virtual address, so all + * userspace consumption of ZONE_DEVICE memory necessitates + * SIGBUS (i.e. MF_MUST_KILL) + */ + flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; + collect_procs_file(pfn_to_page(pfn), mapping, index, &to_kill, + flags & MF_ACTION_REQUIRED); + + unmap_and_kill(&to_kill, pfn, mapping, index, flags); + 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); @@ -1298,12 +1348,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, struct dev_pagemap *pgmap) { struct page *page = pfn_to_page(pfn); - const bool unmap_success = true; - unsigned long size = 0; - struct to_kill *tk; - LIST_HEAD(tokill); + LIST_HEAD(to_kill); int rc = -EBUSY; - loff_t start; dax_entry_t cookie; if (flags & MF_COUNT_INCREASED) @@ -1355,22 +1401,10 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, * SIGBUS (i.e. MF_MUST_KILL) */ flags |= MF_ACTION_REQUIRED | MF_MUST_KILL; - collect_procs(page, &tokill, flags & MF_ACTION_REQUIRED); + collect_procs_file(page, page->mapping, page->index, &to_kill, + flags & MF_ACTION_REQUIRED); - list_for_each_entry(tk, &tokill, nd) - if (tk->size_shift) - size = max(size, 1UL << tk->size_shift); - if (size) { - /* - * Unmap the largest mapping to avoid breaking up - * device-dax mappings which are constant size. The - * actual size of the mapping being torn down is - * communicated in siginfo, see kill_proc() - */ - start = (page->index << PAGE_SHIFT) & ~(size - 1); - unmap_mapping_range(page->mapping, start, size, 0); - } - kill_procs(&tokill, flags & MF_MUST_KILL, !unmap_success, pfn, flags); + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); rc = 0; unlock: dax_unlock_page(page, cookie);
The current memory_failure_dev_pagemap() can only handle single-mapped dax page for fsdax mode. The dax page could be mapped by multiple files and offsets if we let reflink feature & fsdax mode work together. So, we refactor current implementation to support handle memory failure on each file and offset. Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> --- fs/dax.c | 21 ++++++++ include/linux/dax.h | 1 + include/linux/mm.h | 9 ++++ mm/memory-failure.c | 114 ++++++++++++++++++++++++++++---------------- 4 files changed, 105 insertions(+), 40 deletions(-)