| Message ID | 20220419045045.1664996-3-ruansy.fnst@fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fsdax: introduce fs query to support reflink | expand |
On Tue, Apr 19, 2022 at 12:50:40PM +0800, Shiyang Ruan wrote: > memory_failure_dev_pagemap code is a bit complex before introduce RMAP > feature for fsdax. So it is needed to factor some helper functions to > simplify these code. > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > Reviewed-by: Darrick J. Wong <djwong@kernel.org> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Reviewed-by: Dan Williams <dan.j.williams@intel.com> Thanks for the refactoring. As I commented to 0/7, the conflict with "mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb()" can be trivially resolved. Another few comment below ... > --- > mm/memory-failure.c | 157 ++++++++++++++++++++++++-------------------- > 1 file changed, 87 insertions(+), 70 deletions(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index e3fbff5bd467..7c8c047bfdc8 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1498,6 +1498,90 @@ 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; > + > + 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() > + */ > + loff_t start = (index << PAGE_SHIFT) & ~(size - 1); > + > + unmap_mapping_range(mapping, start, size, 0); > + } > + > + kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); > +} > + > +static int mf_generic_kill_procs(unsigned long long pfn, int flags, > + struct dev_pagemap *pgmap) > +{ > + struct page *page = pfn_to_page(pfn); > + LIST_HEAD(to_kill); > + dax_entry_t cookie; > + int rc = 0; > + > + /* > + * Pages instantiated by device-dax (not filesystem-dax) > + * may be compound pages. > + */ > + page = compound_head(page); > + > + /* > + * Prevent the inode from being freed while we are interrogating > + * the address_space, typically this would be handled by > + * lock_page(), but dax pages do not use the page lock. This > + * also prevents changes to the mapping of this pfn until > + * poison signaling is complete. > + */ > + cookie = dax_lock_page(page); > + if (!cookie) > + return -EBUSY; > + > + if (hwpoison_filter(page)) { > + rc = -EOPNOTSUPP; > + goto unlock; > + } > + > + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { > + /* > + * TODO: Handle HMM pages which may need coordination > + * with device-side memory. > + */ > + return -EBUSY; Don't we need to go to dax_unlock_page() as the origincal code do? > + } > + > + /* > + * Use this flag as an indication that the dax page has been > + * remapped UC to prevent speculative consumption of poison. > + */ > + SetPageHWPoison(page); > + > + /* > + * 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(page, &to_kill, true); > + > + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); > +unlock: > + dax_unlock_page(page, cookie); > + return rc; > +} > + > /* > * Called from hugetlb code with hugetlb_lock held. > * > @@ -1644,12 +1728,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, > struct dev_pagemap *pgmap) > { > struct page *page = pfn_to_page(pfn); > - unsigned long size = 0; > - struct to_kill *tk; > LIST_HEAD(tokill); Is this variable unused in this function? Thanks, Naoya Horiguchi
在 2022/4/21 14:13, HORIGUCHI NAOYA(堀口 直也) 写道: > On Tue, Apr 19, 2022 at 12:50:40PM +0800, Shiyang Ruan wrote: >> memory_failure_dev_pagemap code is a bit complex before introduce RMAP >> feature for fsdax. So it is needed to factor some helper functions to >> simplify these code. >> >> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> >> Reviewed-by: Darrick J. Wong <djwong@kernel.org> >> Reviewed-by: Christoph Hellwig <hch@lst.de> >> Reviewed-by: Dan Williams <dan.j.williams@intel.com> > > Thanks for the refactoring. As I commented to 0/7, the conflict with > "mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb()" > can be trivially resolved. > > Another few comment below ... > >> --- >> mm/memory-failure.c | 157 ++++++++++++++++++++++++-------------------- >> 1 file changed, 87 insertions(+), 70 deletions(-) >> >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >> index e3fbff5bd467..7c8c047bfdc8 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -1498,6 +1498,90 @@ 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; >> + >> + 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() >> + */ >> + loff_t start = (index << PAGE_SHIFT) & ~(size - 1); >> + >> + unmap_mapping_range(mapping, start, size, 0); >> + } >> + >> + kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); >> +} >> + >> +static int mf_generic_kill_procs(unsigned long long pfn, int flags, >> + struct dev_pagemap *pgmap) >> +{ >> + struct page *page = pfn_to_page(pfn); >> + LIST_HEAD(to_kill); >> + dax_entry_t cookie; >> + int rc = 0; >> + >> + /* >> + * Pages instantiated by device-dax (not filesystem-dax) >> + * may be compound pages. >> + */ >> + page = compound_head(page); >> + >> + /* >> + * Prevent the inode from being freed while we are interrogating >> + * the address_space, typically this would be handled by >> + * lock_page(), but dax pages do not use the page lock. This >> + * also prevents changes to the mapping of this pfn until >> + * poison signaling is complete. >> + */ >> + cookie = dax_lock_page(page); >> + if (!cookie) >> + return -EBUSY; >> + >> + if (hwpoison_filter(page)) { >> + rc = -EOPNOTSUPP; >> + goto unlock; >> + } >> + >> + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { >> + /* >> + * TODO: Handle HMM pages which may need coordination >> + * with device-side memory. >> + */ >> + return -EBUSY; > > Don't we need to go to dax_unlock_page() as the origincal code do? > >> + } >> + >> + /* >> + * Use this flag as an indication that the dax page has been >> + * remapped UC to prevent speculative consumption of poison. >> + */ >> + SetPageHWPoison(page); >> + >> + /* >> + * 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(page, &to_kill, true); >> + >> + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); >> +unlock: >> + dax_unlock_page(page, cookie); >> + return rc; >> +} >> + >> /* >> * Called from hugetlb code with hugetlb_lock held. >> * >> @@ -1644,12 +1728,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, >> struct dev_pagemap *pgmap) >> { >> struct page *page = pfn_to_page(pfn); >> - unsigned long size = 0; >> - struct to_kill *tk; >> LIST_HEAD(tokill); > > Is this variable unused in this function? Yes, this one and the one above are mistakes I didn't notice when I resolving conflicts with the newer next- branch. I'll fix them in next version. -- Thanks, Ruan. > > Thanks, > Naoya Horiguchi
On 2022/4/21 14:13, HORIGUCHI NAOYA(堀口 直也) wrote: > On Tue, Apr 19, 2022 at 12:50:40PM +0800, Shiyang Ruan wrote: >> memory_failure_dev_pagemap code is a bit complex before introduce RMAP >> feature for fsdax. So it is needed to factor some helper functions to >> simplify these code. >> >> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> >> Reviewed-by: Darrick J. Wong <djwong@kernel.org> >> Reviewed-by: Christoph Hellwig <hch@lst.de> >> Reviewed-by: Dan Williams <dan.j.williams@intel.com> > > Thanks for the refactoring. As I commented to 0/7, the conflict with > "mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb()" > can be trivially resolved. > > Another few comment below ... > >> --- >> mm/memory-failure.c | 157 ++++++++++++++++++++++++-------------------- >> 1 file changed, 87 insertions(+), 70 deletions(-) >> >> diff --git a/mm/memory-failure.c b/mm/memory-failure.c >> index e3fbff5bd467..7c8c047bfdc8 100644 >> --- a/mm/memory-failure.c >> +++ b/mm/memory-failure.c >> @@ -1498,6 +1498,90 @@ 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; >> + >> + 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() >> + */ >> + loff_t start = (index << PAGE_SHIFT) & ~(size - 1); >> + >> + unmap_mapping_range(mapping, start, size, 0); >> + } >> + >> + kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); >> +} >> + >> +static int mf_generic_kill_procs(unsigned long long pfn, int flags, >> + struct dev_pagemap *pgmap) >> +{ >> + struct page *page = pfn_to_page(pfn); >> + LIST_HEAD(to_kill); >> + dax_entry_t cookie; >> + int rc = 0; >> + >> + /* >> + * Pages instantiated by device-dax (not filesystem-dax) >> + * may be compound pages. >> + */ >> + page = compound_head(page); >> + >> + /* >> + * Prevent the inode from being freed while we are interrogating >> + * the address_space, typically this would be handled by >> + * lock_page(), but dax pages do not use the page lock. This >> + * also prevents changes to the mapping of this pfn until >> + * poison signaling is complete. >> + */ >> + cookie = dax_lock_page(page); >> + if (!cookie) >> + return -EBUSY; >> + >> + if (hwpoison_filter(page)) { >> + rc = -EOPNOTSUPP; >> + goto unlock; >> + } >> + >> + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { >> + /* >> + * TODO: Handle HMM pages which may need coordination >> + * with device-side memory. >> + */ >> + return -EBUSY; > > Don't we need to go to dax_unlock_page() as the origincal code do? I think dax_unlock_page is needed too and please remember set rc to -EBUSY before out. > >> + } >> + >> + /* >> + * Use this flag as an indication that the dax page has been >> + * remapped UC to prevent speculative consumption of poison. >> + */ >> + SetPageHWPoison(page); >> + >> + /* >> + * 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(page, &to_kill, true); >> + >> + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); >> +unlock: >> + dax_unlock_page(page, cookie); >> + return rc; >> +} >> + >> /* >> * Called from hugetlb code with hugetlb_lock held. >> * >> @@ -1644,12 +1728,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, >> struct dev_pagemap *pgmap) >> { >> struct page *page = pfn_to_page(pfn); >> - unsigned long size = 0; >> - struct to_kill *tk; >> LIST_HEAD(tokill); > > Is this variable unused in this function? There has a to_kill in mf_generic_kill_procs. So this one is unneeded. We should remove it. > > Thanks, > Naoya Horiguchi > Except for the above nit, the patch looks good to me. Thanks! Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index e3fbff5bd467..7c8c047bfdc8 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1498,6 +1498,90 @@ 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; + + 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() + */ + loff_t start = (index << PAGE_SHIFT) & ~(size - 1); + + unmap_mapping_range(mapping, start, size, 0); + } + + kill_procs(to_kill, flags & MF_MUST_KILL, false, pfn, flags); +} + +static int mf_generic_kill_procs(unsigned long long pfn, int flags, + struct dev_pagemap *pgmap) +{ + struct page *page = pfn_to_page(pfn); + LIST_HEAD(to_kill); + dax_entry_t cookie; + int rc = 0; + + /* + * Pages instantiated by device-dax (not filesystem-dax) + * may be compound pages. + */ + page = compound_head(page); + + /* + * Prevent the inode from being freed while we are interrogating + * the address_space, typically this would be handled by + * lock_page(), but dax pages do not use the page lock. This + * also prevents changes to the mapping of this pfn until + * poison signaling is complete. + */ + cookie = dax_lock_page(page); + if (!cookie) + return -EBUSY; + + if (hwpoison_filter(page)) { + rc = -EOPNOTSUPP; + goto unlock; + } + + if (pgmap->type == MEMORY_DEVICE_PRIVATE) { + /* + * TODO: Handle HMM pages which may need coordination + * with device-side memory. + */ + return -EBUSY; + } + + /* + * Use this flag as an indication that the dax page has been + * remapped UC to prevent speculative consumption of poison. + */ + SetPageHWPoison(page); + + /* + * 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(page, &to_kill, true); + + unmap_and_kill(&to_kill, pfn, page->mapping, page->index, flags); +unlock: + dax_unlock_page(page, cookie); + return rc; +} + /* * Called from hugetlb code with hugetlb_lock held. * @@ -1644,12 +1728,8 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, struct dev_pagemap *pgmap) { struct page *page = pfn_to_page(pfn); - unsigned long size = 0; - struct to_kill *tk; LIST_HEAD(tokill); - int rc = -EBUSY; - loff_t start; - dax_entry_t cookie; + int rc = -ENXIO; if (flags & MF_COUNT_INCREASED) /* @@ -1658,73 +1738,10 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags, put_page(page); /* device metadata space is not recoverable */ - if (!pgmap_pfn_valid(pgmap, pfn)) { - rc = -ENXIO; - goto out; - } - - /* - * Pages instantiated by device-dax (not filesystem-dax) - * may be compound pages. - */ - page = compound_head(page); - - /* - * Prevent the inode from being freed while we are interrogating - * the address_space, typically this would be handled by - * lock_page(), but dax pages do not use the page lock. This - * also prevents changes to the mapping of this pfn until - * poison signaling is complete. - */ - cookie = dax_lock_page(page); - if (!cookie) + if (!pgmap_pfn_valid(pgmap, pfn)) goto out; - if (hwpoison_filter(page)) { - rc = -EOPNOTSUPP; - goto unlock; - } - - if (pgmap->type == MEMORY_DEVICE_PRIVATE) { - /* - * TODO: Handle HMM pages which may need coordination - * with device-side memory. - */ - goto unlock; - } - - /* - * Use this flag as an indication that the dax page has been - * remapped UC to prevent speculative consumption of poison. - */ - SetPageHWPoison(page); - - /* - * 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(page, &tokill, true); - - 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, true, false, pfn, flags); - rc = 0; -unlock: - dax_unlock_page(page, cookie); + rc = mf_generic_kill_procs(pfn, flags, pgmap); out: /* drop pgmap ref acquired in caller */ put_dev_pagemap(pgmap);