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+ mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/khugepaged: fix crashes due to misaccounted holes has been added to the -mm tree. Its filename is mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-khugepaged-fix-crashes-due-to-m… and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-khugepaged-fix-crashes-due-to-m… Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/khugepaged: fix crashes due to misaccounted holes Huge tmpfs testing on a shortish file mapped into a pmd-rounded extent hit shmem_evict_inode()'s WARN_ON(inode->i_blocks) followed by clear_inode()'s BUG_ON(inode->i_data.nrpages) when the file was later closed and unlinked. khugepaged's collapse_shmem() was forgetting to update mapping->nrpages on the rollback path, after it had added but then needs to undo some holes. There is indeed an irritating asymmetry between shmem_charge(), whose callers want it to increment nrpages after successfully accounting blocks, and shmem_uncharge(), when __delete_from_page_cache() already decremented nrpages itself: oh well, just add a comment on that to them both. And shmem_recalc_inode() is supposed to be called when the accounting is expected to be in balance (so it can deduce from imbalance that reclaim discarded some pages): so change shmem_charge() to update nrpages earlier (though it's rare for the difference to matter at all). Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261523450.2275@eggly.anvils Fixes: 800d8c63b2e98 ("shmem: add huge pages support") Fixes: f3f0e1d2150b2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: Jerome Glisse <jglisse(a)redhat.com> Cc: Konstantin Khlebnikov <khlebnikov(a)yandex-team.ru> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/mm/khugepaged.c~mm-khugepaged-fix-crashes-due-to-misaccounted-holes +++ a/mm/khugepaged.c @@ -1506,9 +1506,12 @@ xa_unlocked: khugepaged_pages_collapsed++; } else { struct page *page; + /* Something went wrong: roll back page cache changes */ - shmem_uncharge(mapping->host, nr_none); xas_lock_irq(&xas); + mapping->nrpages -= nr_none; + shmem_uncharge(mapping->host, nr_none); + xas_set(&xas, start); xas_for_each(&xas, page, end - 1) { page = list_first_entry_or_null(&pagelist, --- a/mm/shmem.c~mm-khugepaged-fix-crashes-due-to-misaccounted-holes +++ a/mm/shmem.c @@ -297,12 +297,14 @@ bool shmem_charge(struct inode *inode, l if (!shmem_inode_acct_block(inode, pages)) return false; + /* nrpages adjustment first, then shmem_recalc_inode() when balanced */ + inode->i_mapping->nrpages += pages; + spin_lock_irqsave(&info->lock, flags); info->alloced += pages; inode->i_blocks += pages * BLOCKS_PER_PAGE; shmem_recalc_inode(inode); spin_unlock_irqrestore(&info->lock, flags); - inode->i_mapping->nrpages += pages; return true; } @@ -312,6 +314,8 @@ void shmem_uncharge(struct inode *inode, struct shmem_inode_info *info = SHMEM_I(inode); unsigned long flags; + /* nrpages adjustment done by __delete_from_page_cache() or caller */ + spin_lock_irqsave(&info->lock, flags); info->alloced -= pages; inode->i_blocks -= pages * BLOCKS_PER_PAGE; _ Patches currently in -mm which might be from hughd(a)google.com are mm-huge_memory-rename-freeze_page-to-unmap_page.patch mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch mm-khugepaged-minor-reorderings-in-collapse_shmem.patch mm-khugepaged-collapse_shmem-without-freezing-new_page.patch mm-khugepaged-collapse_shmem-do-not-crash-on-compound.patch mm-khugepaged-fix-the-xas_create_range-error-path.patch mm-put_and_wait_on_page_locked-while-page-is-migrated.patch

7 years, 1 month

+ mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/khugepaged: collapse_shmem() stop if punched or truncated has been added to the -mm tree. Its filename is mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-khugepaged-collapse_shmem-stop-… and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-khugepaged-collapse_shmem-stop-… Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/khugepaged: collapse_shmem() stop if punched or truncated Huge tmpfs testing showed that although collapse_shmem() recognizes a concurrently truncated or hole-punched page correctly, its handling of holes was liable to refill an emptied extent. Add check to stop that. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261522040.2275@eggly.anvils Fixes: f3f0e1d2150b2 ("khugepaged: add support of collapse for tmpfs/shmem pages") Signed-off-by: Hugh Dickins <hughd(a)google.com> Reviewed-by: Matthew Wilcox <willy(a)infradead.org> Cc: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: Jerome Glisse <jglisse(a)redhat.com> Cc: Konstantin Khlebnikov <khlebnikov(a)yandex-team.ru> Cc: <stable(a)vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/mm/khugepaged.c~mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated +++ a/mm/khugepaged.c @@ -1359,6 +1359,17 @@ static void collapse_shmem(struct mm_str VM_BUG_ON(index != xas.xa_index); if (!page) { + /* + * Stop if extent has been truncated or hole-punched, + * and is now completely empty. + */ + if (index == start) { + if (!xas_next_entry(&xas, end - 1)) { + result = SCAN_TRUNCATED; + break; + } + xas_set(&xas, index); + } if (!shmem_charge(mapping->host, 1)) { result = SCAN_FAIL; break; _ Patches currently in -mm which might be from hughd(a)google.com are mm-huge_memory-rename-freeze_page-to-unmap_page.patch mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch mm-khugepaged-minor-reorderings-in-collapse_shmem.patch mm-khugepaged-collapse_shmem-without-freezing-new_page.patch mm-khugepaged-collapse_shmem-do-not-crash-on-compound.patch mm-khugepaged-fix-the-xas_create_range-error-path.patch mm-put_and_wait_on_page_locked-while-page-is-migrated.patch

7 years, 1 month

+ mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/huge_memory: fix lockdep complaint on 32-bit i_size_read() has been added to the -mm tree. Its filename is mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-fix-lockdep-complai… and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-fix-lockdep-complai… Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/huge_memory: fix lockdep complaint on 32-bit i_size_read() Huge tmpfs testing, on 32-bit kernel with lockdep enabled, showed that __split_huge_page() was using i_size_read() while holding the irq-safe lru_lock and page tree lock, but the 32-bit i_size_read() uses an irq-unsafe seqlock which should not be nested inside them. Instead, read the i_size earlier in split_huge_page_to_list(), and pass the end offset down to __split_huge_page(): all while holding head page lock, which is enough to prevent truncation of that extent before the page tree lock has been taken. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261520070.2275@eggly.anvils Fixes: baa355fd33142 ("thp: file pages support for split_huge_page()") Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: Jerome Glisse <jglisse(a)redhat.com> Cc: Konstantin Khlebnikov <khlebnikov(a)yandex-team.ru> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/mm/huge_memory.c~mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read +++ a/mm/huge_memory.c @@ -2439,12 +2439,11 @@ static void __split_huge_page_tail(struc } static void __split_huge_page(struct page *page, struct list_head *list, - unsigned long flags) + pgoff_t end, unsigned long flags) { struct page *head = compound_head(page); struct zone *zone = page_zone(head); struct lruvec *lruvec; - pgoff_t end = -1; int i; lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat); @@ -2452,9 +2451,6 @@ static void __split_huge_page(struct pag /* complete memcg works before add pages to LRU */ mem_cgroup_split_huge_fixup(head); - if (!PageAnon(page)) - end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE); - for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { __split_huge_page_tail(head, i, lruvec, list); /* Some pages can be beyond i_size: drop them from page cache */ @@ -2626,6 +2622,7 @@ int split_huge_page_to_list(struct page int count, mapcount, extra_pins, ret; bool mlocked; unsigned long flags; + pgoff_t end; VM_BUG_ON_PAGE(is_huge_zero_page(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page); @@ -2648,6 +2645,7 @@ int split_huge_page_to_list(struct page ret = -EBUSY; goto out; } + end = -1; mapping = NULL; anon_vma_lock_write(anon_vma); } else { @@ -2661,6 +2659,15 @@ int split_huge_page_to_list(struct page anon_vma = NULL; i_mmap_lock_read(mapping); + + /* + *__split_huge_page() may need to trim off pages beyond EOF: + * but on 32-bit, i_size_read() takes an irq-unsafe seqlock, + * which cannot be nested inside the page tree lock. So note + * end now: i_size itself may be changed at any moment, but + * head page lock is good enough to serialize the trimming. + */ + end = DIV_ROUND_UP(i_size_read(mapping->host), PAGE_SIZE); } /* @@ -2707,7 +2714,7 @@ int split_huge_page_to_list(struct page if (mapping) __dec_node_page_state(page, NR_SHMEM_THPS); spin_unlock(&pgdata->split_queue_lock); - __split_huge_page(page, list, flags); + __split_huge_page(page, list, end, flags); if (PageSwapCache(head)) { swp_entry_t entry = { .val = page_private(head) }; _ Patches currently in -mm which might be from hughd(a)google.com are mm-huge_memory-rename-freeze_page-to-unmap_page.patch mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch mm-khugepaged-minor-reorderings-in-collapse_shmem.patch mm-khugepaged-collapse_shmem-without-freezing-new_page.patch mm-khugepaged-collapse_shmem-do-not-crash-on-compound.patch mm-khugepaged-fix-the-xas_create_range-error-path.patch mm-put_and_wait_on_page_locked-while-page-is-migrated.patch

7 years, 1 month

+ mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/huge_memory: splitting set mapping+index before unfreeze has been added to the -mm tree. Its filename is mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-splitting-set-mappi… and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-splitting-set-mappi… Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/huge_memory: splitting set mapping+index before unfreeze Huge tmpfs stress testing has occasionally hit shmem_undo_range()'s VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page). Move the setting of mapping and index up before the page_ref_unfreeze() in __split_huge_page_tail() to fix this: so that a page cache lookup cannot get a reference while the tail's mapping and index are unstable. In fact, might as well move them up before the smp_wmb(): I don't see an actual need for that, but if I'm missing something, this way round is safer than the other, and no less efficient. You might argue that VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page) is misplaced, and should be left until after the trylock_page(); but left as is has not crashed since, and gives more stringent assurance. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261516380.2275@eggly.anvils Fixes: e9b61f19858a5 ("thp: reintroduce split_huge_page()") Requires: 605ca5ede764 ("mm/huge_memory.c: reorder operations in __split_huge_page_tail()") Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov(a)yandex-team.ru> Cc: Jerome Glisse <jglisse(a)redhat.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/mm/huge_memory.c~mm-huge_memory-splitting-set-mappingindex-before-unfreeze +++ a/mm/huge_memory.c @@ -2402,6 +2402,12 @@ static void __split_huge_page_tail(struc (1L << PG_unevictable) | (1L << PG_dirty))); + /* ->mapping in first tail page is compound_mapcount */ + VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, + page_tail); + page_tail->mapping = head->mapping; + page_tail->index = head->index + tail; + /* Page flags must be visible before we make the page non-compound. */ smp_wmb(); @@ -2422,12 +2428,6 @@ static void __split_huge_page_tail(struc if (page_is_idle(head)) set_page_idle(page_tail); - /* ->mapping in first tail page is compound_mapcount */ - VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING, - page_tail); - page_tail->mapping = head->mapping; - - page_tail->index = head->index + tail; page_cpupid_xchg_last(page_tail, page_cpupid_last(head)); /* _ Patches currently in -mm which might be from hughd(a)google.com are mm-huge_memory-rename-freeze_page-to-unmap_page.patch mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch mm-khugepaged-minor-reorderings-in-collapse_shmem.patch mm-khugepaged-collapse_shmem-without-freezing-new_page.patch mm-khugepaged-collapse_shmem-do-not-crash-on-compound.patch mm-khugepaged-fix-the-xas_create_range-error-path.patch mm-put_and_wait_on_page_locked-while-page-is-migrated.patch

7 years, 1 month

+ mm-huge_memory-rename-freeze_page-to-unmap_page.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/huge_memory: rename freeze_page() to unmap_page() has been added to the -mm tree. Its filename is mm-huge_memory-rename-freeze_page-to-unmap_page.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-rename-freeze_page-… and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-rename-freeze_page-… Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/huge_memory: rename freeze_page() to unmap_page() The term "freeze" is used in several ways in the kernel, and in mm it has the particular meaning of forcing page refcount temporarily to 0. freeze_page() is just too confusing a name for a function that unmaps a page: rename it unmap_page(), and rename unfreeze_page() remap_page(). Went to change the mention of freeze_page() added later in mm/rmap.c, but found it to be incorrect: ordinary page reclaim reaches there too; but the substance of the comment still seems correct, so edit it down. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261514080.2275@eggly.anvils Fixes: e9b61f19858a5 ("thp: reintroduce split_huge_page()") Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: Jerome Glisse <jglisse(a)redhat.com> Cc: Konstantin Khlebnikov <khlebnikov(a)yandex-team.ru> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: <stable(a)vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- --- a/mm/huge_memory.c~mm-huge_memory-rename-freeze_page-to-unmap_page +++ a/mm/huge_memory.c @@ -2350,7 +2350,7 @@ void vma_adjust_trans_huge(struct vm_are } } -static void freeze_page(struct page *page) +static void unmap_page(struct page *page) { enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; @@ -2365,7 +2365,7 @@ static void freeze_page(struct page *pag VM_BUG_ON_PAGE(!unmap_success, page); } -static void unfreeze_page(struct page *page) +static void remap_page(struct page *page) { int i; if (PageTransHuge(page)) { @@ -2483,7 +2483,7 @@ static void __split_huge_page(struct pag spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); - unfreeze_page(head); + remap_page(head); for (i = 0; i < HPAGE_PMD_NR; i++) { struct page *subpage = head + i; @@ -2664,7 +2664,7 @@ int split_huge_page_to_list(struct page } /* - * Racy check if we can split the page, before freeze_page() will + * Racy check if we can split the page, before unmap_page() will * split PMDs */ if (!can_split_huge_page(head, &extra_pins)) { @@ -2673,7 +2673,7 @@ int split_huge_page_to_list(struct page } mlocked = PageMlocked(page); - freeze_page(head); + unmap_page(head); VM_BUG_ON_PAGE(compound_mapcount(head), head); /* Make sure the page is not on per-CPU pagevec as it takes pin */ @@ -2727,7 +2727,7 @@ int split_huge_page_to_list(struct page fail: if (mapping) xa_unlock(&mapping->i_pages); spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags); - unfreeze_page(head); + remap_page(head); ret = -EBUSY; } --- a/mm/rmap.c~mm-huge_memory-rename-freeze_page-to-unmap_page +++ a/mm/rmap.c @@ -1627,16 +1627,9 @@ static bool try_to_unmap_one(struct page address + PAGE_SIZE); } else { /* - * We should not need to notify here as we reach this - * case only from freeze_page() itself only call from - * split_huge_page_to_list() so everything below must - * be true: - * - page is not anonymous - * - page is locked - * - * So as it is a locked file back page thus it can not - * be remove from the page cache and replace by a new - * page before mmu_notifier_invalidate_range_end so no + * This is a locked file-backed page, thus it cannot + * be removed from the page cache and replaced by a new + * page before mmu_notifier_invalidate_range_end, so no * concurrent thread might update its page table to * point at new page while a device still is using this * page. _ Patches currently in -mm which might be from hughd(a)google.com are mm-huge_memory-rename-freeze_page-to-unmap_page.patch mm-huge_memory-splitting-set-mappingindex-before-unfreeze.patch mm-huge_memory-fix-lockdep-complaint-on-32-bit-i_size_read.patch mm-khugepaged-collapse_shmem-stop-if-punched-or-truncated.patch mm-khugepaged-fix-crashes-due-to-misaccounted-holes.patch mm-khugepaged-collapse_shmem-remember-to-clear-holes.patch mm-khugepaged-minor-reorderings-in-collapse_shmem.patch mm-khugepaged-collapse_shmem-without-freezing-new_page.patch mm-khugepaged-collapse_shmem-do-not-crash-on-compound.patch mm-khugepaged-fix-the-xas_create_range-error-path.patch mm-put_and_wait_on_page_locked-while-page-is-migrated.patch

7 years, 1 month

[PATCH] scsi: storvsc: Fix a race in sub-channel creation that can cause panic

by kys＠linuxonhyperv.com

From: Dexuan Cui <decui(a)microsoft.com> We can concurrently try to open the same sub-channel from 2 paths: path #1: vmbus_onoffer() -> vmbus_process_offer() -> handle_sc_creation(). path #2: storvsc_probe() -> storvsc_connect_to_vsp() -> -> storvsc_channel_init() -> handle_multichannel_storage() -> -> vmbus_are_subchannels_present() -> handle_sc_creation(). They conflict with each other, but it was not an issue before the recent commit ae6935ed7d42 ("vmbus: split ring buffer allocation from open"), because at the beginning of vmbus_open() we checked newchannel->state so only one path could succeed, and the other would return with -EINVAL. After ae6935ed7d42, the failing path frees the channel's ringbuffer by vmbus_free_ring(), and this causes a panic later. Commit ae6935ed7d42 itself is good, and it just reveals the longstanding race. We can resolve the issue by removing path #2, i.e. removing the second vmbus_are_subchannels_present() in handle_multichannel_storage(). BTW, the comment "Check to see if sub-channels have already been created" in handle_multichannel_storage() is incorrect: when we unload the driver, we first close the sub-channel(s) and then close the primary channel, next the host sends rescind-offer message(s) so primary->sc_list will become empty. This means the first vmbus_are_subchannels_present() in handle_multichannel_storage() is never useful. Fixes: ae6935ed7d42 ("vmbus: split ring buffer allocation from open") Cc: stable(a)vger.kernel.org Cc: Long Li <longli(a)microsoft.com> Cc: Stephen Hemminger <sthemmin(a)microsoft.com> Cc: K. Y. Srinivasan <kys(a)microsoft.com> Cc: Haiyang Zhang <haiyangz(a)microsoft.com> Signed-off-by: Dexuan Cui <decui(a)microsoft.com> Signed-off-by: K. Y. Srinivasan <kys(a)microsoft.com> --- drivers/scsi/storvsc_drv.c | 61 +++++++++++++++++++------------------- 1 file changed, 30 insertions(+), 31 deletions(-) diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index f03dc03a42c3..8f88348ebe42 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -446,7 +446,6 @@ struct storvsc_device { bool destroy; bool drain_notify; - bool open_sub_channel; atomic_t num_outstanding_req; struct Scsi_Host *host; @@ -636,33 +635,38 @@ static inline struct storvsc_device *get_in_stor_device( static void handle_sc_creation(struct vmbus_channel *new_sc) { struct hv_device *device = new_sc->primary_channel->device_obj; + struct device *dev = &device->device; struct storvsc_device *stor_device; struct vmstorage_channel_properties props; + int ret; stor_device = get_out_stor_device(device); if (!stor_device) return; - if (stor_device->open_sub_channel == false) - return; - memset(&props, 0, sizeof(struct vmstorage_channel_properties)); - vmbus_open(new_sc, - storvsc_ringbuffer_size, - storvsc_ringbuffer_size, - (void *)&props, - sizeof(struct vmstorage_channel_properties), - storvsc_on_channel_callback, new_sc); + ret = vmbus_open(new_sc, + storvsc_ringbuffer_size, + storvsc_ringbuffer_size, + (void *)&props, + sizeof(struct vmstorage_channel_properties), + storvsc_on_channel_callback, new_sc); - if (new_sc->state == CHANNEL_OPENED_STATE) { - stor_device->stor_chns[new_sc->target_cpu] = new_sc; - cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus); + /* In case vmbus_open() fails, we don't use the sub-channel. */ + if (ret != 0) { + dev_err(dev, "Failed to open sub-channel: err=%d\n", ret); + return; } + + /* Add the sub-channel to the array of available channels. */ + stor_device->stor_chns[new_sc->target_cpu] = new_sc; + cpumask_set_cpu(new_sc->target_cpu, &stor_device->alloced_cpus); } static void handle_multichannel_storage(struct hv_device *device, int max_chns) { + struct device *dev = &device->device; struct storvsc_device *stor_device; int num_cpus = num_online_cpus(); int num_sc; @@ -679,21 +683,11 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns) request = &stor_device->init_request; vstor_packet = &request->vstor_packet; - stor_device->open_sub_channel = true; /* * Establish a handler for dealing with subchannels. */ vmbus_set_sc_create_callback(device->channel, handle_sc_creation); - /* - * Check to see if sub-channels have already been created. This - * can happen when this driver is re-loaded after unloading. - */ - - if (vmbus_are_subchannels_present(device->channel)) - return; - - stor_device->open_sub_channel = false; /* * Request the host to create sub-channels. */ @@ -710,23 +704,29 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns) VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); - if (ret != 0) + if (ret != 0) { + dev_err(dev, "Failed to create sub-channel: err=%d\n", ret); return; + } t = wait_for_completion_timeout(&request->wait_event, 10*HZ); - if (t == 0) + if (t == 0) { + dev_err(dev, "Failed to create sub-channel: timed out\n"); return; + } if (vstor_packet->operation != VSTOR_OPERATION_COMPLETE_IO || - vstor_packet->status != 0) + vstor_packet->status != 0) { + dev_err(dev, "Failed to create sub-channel: op=%d, sts=%d\n", + vstor_packet->operation, vstor_packet->status); return; + } /* - * Now that we created the sub-channels, invoke the check; this - * may trigger the callback. + * We need to do nothing here, because vmbus_process_offer() + * invokes channel->sc_creation_callback, which will open and use + * the sub-channel(s). */ - stor_device->open_sub_channel = true; - vmbus_are_subchannels_present(device->channel); } static void cache_wwn(struct storvsc_device *stor_device, @@ -1794,7 +1794,6 @@ static int storvsc_probe(struct hv_device *device, } stor_device->destroy = false; - stor_device->open_sub_channel = false; init_waitqueue_head(&stor_device->waiting_to_drain); stor_device->device = device; stor_device->host = host; -- 2.19.1

7 years, 1 month

[PATCH v3 2/7] zram: fix double free backing device

by Minchan Kim

If blkdev_get fails, we shouldn't do blkdev_put. Otherwise, kernel emits below log. This patch fixes it. [ 31.073006] WARNING: CPU: 0 PID: 1893 at fs/block_dev.c:1828 blkdev_put+0x105/0x120 [ 31.075104] Modules linked in: [ 31.075898] CPU: 0 PID: 1893 Comm: swapoff Not tainted 4.19.0+ #453 [ 31.077484] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 31.079589] RIP: 0010:blkdev_put+0x105/0x120 [ 31.080606] Code: 48 c7 80 a0 00 00 00 00 00 00 00 48 c7 c7 40 e7 40 96 e8 6e 47 73 00 48 8b bb e0 00 00 00 e9 2c ff ff ff 0f 0b e9 75 ff ff ff <0f> 0b e9 5a ff ff ff 48 c7 80 a0 00 00 00 00 00 00 00 eb 87 0f 1f [ 31.085080] RSP: 0018:ffffb409005c7ed0 EFLAGS: 00010297 [ 31.086383] RAX: ffff9779fe5a8040 RBX: ffff9779fbc17300 RCX: 00000000b9fc37a4 [ 31.088105] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffffff9640e740 [ 31.089850] RBP: ffff9779fbc17318 R08: ffffffff95499a89 R09: 0000000000000004 [ 31.091201] R10: ffffb409005c7e50 R11: 7a9ef6088ff4d4a1 R12: 0000000000000083 [ 31.092276] R13: ffff9779fe607b98 R14: 0000000000000000 R15: ffff9779fe607a38 [ 31.093355] FS: 00007fc118d9b840(0000) GS:ffff9779fc600000(0000) knlGS:0000000000000000 [ 31.094582] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 31.095541] CR2: 00007fc11894b8dc CR3: 00000000339f6001 CR4: 0000000000160ef0 [ 31.096781] Call Trace: [ 31.097212] __x64_sys_swapoff+0x46d/0x490 [ 31.097914] do_syscall_64+0x5a/0x190 [ 31.098550] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 31.099402] RIP: 0033:0x7fc11843ec27 [ 31.100013] Code: 73 01 c3 48 8b 0d 71 62 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 a8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 41 62 2c 00 f7 d8 64 89 01 48 [ 31.103149] RSP: 002b:00007ffdf69be648 EFLAGS: 00000206 ORIG_RAX: 00000000000000a8 [ 31.104425] RAX: ffffffffffffffda RBX: 00000000011d98c0 RCX: 00007fc11843ec27 [ 31.105627] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 00000000011d98c0 [ 31.106847] RBP: 0000000000000001 R08: 00007ffdf69be690 R09: 0000000000000001 [ 31.108038] R10: 00000000000002b1 R11: 0000000000000206 R12: 0000000000000001 [ 31.109231] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 31.110433] irq event stamp: 4466 [ 31.111001] hardirqs last enabled at (4465): [<ffffffff953ebd43>] __free_pages_ok+0x1e3/0x490 [ 31.112437] hardirqs last disabled at (4466): [<ffffffff95201b7a>] trace_hardirqs_off_thunk+0x1a/0x1c [ 31.113973] softirqs last enabled at (3420): [<ffffffff95e00333>] __do_softirq+0x333/0x446 [ 31.115364] softirqs last disabled at (3407): [<ffffffff9527aee1>] irq_exit+0xd1/0xe0 Cc: stable(a)vger.kernel.org # 4.14+ Signed-off-by: Minchan Kim <minchan(a)kernel.org> --- drivers/block/zram/zram_drv.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 21a7046958a3..d1459cc1159f 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -387,8 +387,10 @@ static ssize_t backing_dev_store(struct device *dev, bdev = bdgrab(I_BDEV(inode)); err = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram); - if (err < 0) + if (err < 0) { + bdev = NULL; goto out; + } nr_pages = i_size_read(inode) >> PAGE_SHIFT; bitmap_sz = BITS_TO_LONGS(nr_pages) * sizeof(long); -- 2.20.0.rc0.387.gc7a69e6b6c-goog

7 years, 1 month

[PATCH] drm/amdgpu: don't expose fan attributes on APUs

by Alex Deucher

They don't have a fan controller. Signed-off-by: Alex Deucher <alexander.deucher(a)amd.com> Cc: stable(a)vger.kernel.org --- drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c index 0de8650c5d6e..1f61ed95727c 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c @@ -1644,6 +1644,19 @@ static umode_t hwmon_attributes_visible(struct kobject *kobj, attr == &sensor_dev_attr_fan1_enable.dev_attr.attr)) return 0; + /* Skip fan attributes on APU */ + if ((adev->flags & AMD_IS_APU) && + (attr == &sensor_dev_attr_pwm1.dev_attr.attr || + attr == &sensor_dev_attr_pwm1_enable.dev_attr.attr || + attr == &sensor_dev_attr_pwm1_max.dev_attr.attr || + attr == &sensor_dev_attr_pwm1_min.dev_attr.attr || + attr == &sensor_dev_attr_fan1_input.dev_attr.attr || + attr == &sensor_dev_attr_fan1_min.dev_attr.attr || + attr == &sensor_dev_attr_fan1_max.dev_attr.attr || + attr == &sensor_dev_attr_fan1_target.dev_attr.attr || + attr == &sensor_dev_attr_fan1_enable.dev_attr.attr)) + return 0; + /* Skip limit attributes if DPM is not enabled */ if (!adev->pm.dpm_enabled && (attr == &sensor_dev_attr_temp1_crit.dev_attr.attr || -- 2.13.6

7 years, 1 month

+ zram-writeback-throttle.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: zram: writeback throttle has been added to the -mm tree. Its filename is zram-writeback-throttle.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/zram-writeback-throttle.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/zram-writeback-throttle.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Minchan Kim <minchan(a)kernel.org> Subject: zram: writeback throttle On small memory systems there are lots of write IOs so if we use a flash device as swap there would be serious flash wearout. To overcome this problem, system developers need to design a write limitation strategy to guarantee flash health for the entire product life. This patch creates a new knob "writeback_limit" on zram. With that, if the current writeback IO count (/sys/block/zramX/io_stat) exceeds the limitation, zram stops further writeback until the admin can reset the limit. Link: http://lkml.kernel.org/r/20181127055429.251614-8-minchan@kernel.org Signed-off-by: Minchan Kim <minchan(a)kernel.org> Cc: Joey Pabalinas <joeypabalinas(a)gmail.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work(a)gmail.com> Cc: <stable(a)vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- Documentation/ABI/testing/sysfs-block-zram | 9 +++ Documentation/blockdev/zram.txt | 2 drivers/block/zram/zram_drv.c | 47 ++++++++++++++++++- drivers/block/zram/zram_drv.h | 2 4 files changed, 59 insertions(+), 1 deletion(-) --- a/Documentation/ABI/testing/sysfs-block-zram~zram-writeback-throttle +++ a/Documentation/ABI/testing/sysfs-block-zram @@ -121,3 +121,12 @@ Description: The bd_stat file is read-only and represents backing device's statistics (bd_count, bd_reads, bd_writes) in a format similar to block layer statistics file format. + +What: /sys/block/zram<id>/writeback_limit +Date: November 2018 +Contact: Minchan Kim <minchan(a)kernel.org> +Description: + The writeback_limit file is read-write and specifies the maximum + amount of writeback ZRAM can do. The limit could be changed + in run time and "0" means disable the limit. + No limit is the initial state. --- a/Documentation/blockdev/zram.txt~zram-writeback-throttle +++ a/Documentation/blockdev/zram.txt @@ -164,6 +164,8 @@ reset WO trigger device r mem_used_max WO reset the `mem_used_max' counter (see later) mem_limit WO specifies the maximum amount of memory ZRAM can use to store the compressed data +writeback_limit WO specifies the maximum amount of write IO zram can + write out to backing device as 4KB unit max_comp_streams RW the number of possible concurrent compress operations comp_algorithm RW show and change the compression algorithm compact WO trigger memory compaction --- a/drivers/block/zram/zram_drv.c~zram-writeback-throttle +++ a/drivers/block/zram/zram_drv.c @@ -330,6 +330,40 @@ next: } #ifdef CONFIG_ZRAM_WRITEBACK + +static ssize_t writeback_limit_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t len) +{ + struct zram *zram = dev_to_zram(dev); + u64 val; + ssize_t ret = -EINVAL; + + if (kstrtoull(buf, 10, &val)) + return ret; + + down_read(&zram->init_lock); + atomic64_set(&zram->stats.bd_wb_limit, val); + if (val == 0 || val > atomic64_read(&zram->stats.bd_writes)) + zram->stop_writeback = false; + up_read(&zram->init_lock); + ret = len; + + return ret; +} + +static ssize_t writeback_limit_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + u64 val; + struct zram *zram = dev_to_zram(dev); + + down_read(&zram->init_lock); + val = atomic64_read(&zram->stats.bd_wb_limit); + up_read(&zram->init_lock); + + return scnprintf(buf, PAGE_SIZE, "%llu\n", val); +} + static void reset_bdev(struct zram *zram) { struct block_device *bdev; @@ -571,6 +605,7 @@ static ssize_t writeback_store(struct de char mode_buf[8]; unsigned long mode = -1UL; unsigned long blk_idx = 0; + u64 wb_count, wb_limit; sz = strscpy(mode_buf, buf, sizeof(mode_buf)); if (sz <= 0) @@ -612,6 +647,11 @@ static ssize_t writeback_store(struct de bvec.bv_len = PAGE_SIZE; bvec.bv_offset = 0; + if (zram->stop_writeback) { + ret = -EIO; + break; + } + if (!blk_idx) { blk_idx = alloc_block_bdev(zram); if (!blk_idx) { @@ -670,7 +710,7 @@ static ssize_t writeback_store(struct de continue; } - atomic64_inc(&zram->stats.bd_writes); + wb_count = atomic64_inc_return(&zram->stats.bd_writes); /* * We released zram_slot_lock so need to check if the slot was * changed. If there is freeing for the slot, we can catch it @@ -694,6 +734,9 @@ static ssize_t writeback_store(struct de zram_set_element(zram, index, blk_idx); blk_idx = 0; atomic64_inc(&zram->stats.pages_stored); + wb_limit = atomic64_read(&zram->stats.bd_wb_limit); + if (wb_limit != 0 && wb_count >= wb_limit) + zram->stop_writeback = true; next: zram_slot_unlock(zram, index); } @@ -1767,6 +1810,7 @@ static DEVICE_ATTR_RW(comp_algorithm); #ifdef CONFIG_ZRAM_WRITEBACK static DEVICE_ATTR_RW(backing_dev); static DEVICE_ATTR_WO(writeback); +static DEVICE_ATTR_RW(writeback_limit); #endif static struct attribute *zram_disk_attrs[] = { @@ -1782,6 +1826,7 @@ static struct attribute *zram_disk_attrs #ifdef CONFIG_ZRAM_WRITEBACK &dev_attr_backing_dev.attr, &dev_attr_writeback.attr, + &dev_attr_writeback_limit.attr, #endif &dev_attr_io_stat.attr, &dev_attr_mm_stat.attr, --- a/drivers/block/zram/zram_drv.h~zram-writeback-throttle +++ a/drivers/block/zram/zram_drv.h @@ -86,6 +86,7 @@ struct zram_stats { atomic64_t bd_count; /* no. of pages in backing device */ atomic64_t bd_reads; /* no. of reads from backing device */ atomic64_t bd_writes; /* no. of writes from backing device */ + atomic64_t bd_wb_limit; /* writeback limit of backing device */ #endif }; @@ -113,6 +114,7 @@ struct zram { */ bool claim; /* Protected by bdev->bd_mutex */ struct file *backing_dev; + bool stop_writeback; #ifdef CONFIG_ZRAM_WRITEBACK struct block_device *bdev; unsigned int old_block_size; _ Patches currently in -mm which might be from minchan(a)kernel.org are zram-fix-lockdep-warning-of-free-block-handling.patch zram-fix-double-free-backing-device.patch zram-refactoring-flags-and-writeback-stuff.patch zram-introduce-zram_idle-flag.patch zram-support-idle-huge-page-writeback.patch zram-add-bd_stat-statistics.patch zram-writeback-throttle.patch

7 years, 1 month

+ zram-add-bd_stat-statistics.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: zram: add bd_stat statistics has been added to the -mm tree. Its filename is zram-add-bd_stat-statistics.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/zram-add-bd_stat-statistics.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/zram-add-bd_stat-statistics.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Minchan Kim <minchan(a)kernel.org> Subject: zram: add bd_stat statistics bd_stat represents things that happened in the backing device. Currently it supports bd_counts, bd_reads and bd_writes which are helpful to understand wearout of flash and memory saving. Link: http://lkml.kernel.org/r/20181127055429.251614-7-minchan@kernel.org Signed-off-by: Minchan Kim <minchan(a)kernel.org> Cc: Joey Pabalinas <joeypabalinas(a)gmail.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work(a)gmail.com> Cc: <stable(a)vger.kernel.org> [4.14+] Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- Documentation/ABI/testing/sysfs-block-zram | 8 +++++ Documentation/blockdev/zram.txt | 11 +++++++ drivers/block/zram/zram_drv.c | 29 +++++++++++++++++++ drivers/block/zram/zram_drv.h | 5 +++ 4 files changed, 53 insertions(+) --- a/Documentation/ABI/testing/sysfs-block-zram~zram-add-bd_stat-statistics +++ a/Documentation/ABI/testing/sysfs-block-zram @@ -113,3 +113,11 @@ Contact: Minchan Kim <minchan(a)kernel.org Description: The writeback file is write-only and trigger idle and/or huge page writeback to backing device. + +What: /sys/block/zram<id>/bd_stat +Date: November 2018 +Contact: Minchan Kim <minchan(a)kernel.org> +Description: + The bd_stat file is read-only and represents backing device's + statistics (bd_count, bd_reads, bd_writes) in a format + similar to block layer statistics file format. --- a/Documentation/blockdev/zram.txt~zram-add-bd_stat-statistics +++ a/Documentation/blockdev/zram.txt @@ -221,6 +221,17 @@ line of text and contains the following pages_compacted the number of pages freed during compaction huge_pages the number of incompressible pages +File /sys/block/zram<id>/bd_stat + +The stat file represents device's backing device statistics. It consists of +a single line of text and contains the following stats separated by whitespace: + bd_count size of data written in backing device. + Unit: 4K bytes + bd_reads the number of reads from backing device + Unit: 4K bytes + bd_writes the number of writes to backing device + Unit: 4K bytes + 9) Deactivate: swapoff /dev/zram0 umount /dev/zram1 --- a/drivers/block/zram/zram_drv.c~zram-add-bd_stat-statistics +++ a/drivers/block/zram/zram_drv.c @@ -502,6 +502,7 @@ retry: if (test_and_set_bit(blk_idx, zram->bitmap)) goto retry; + atomic64_inc(&zram->stats.bd_count); return blk_idx; } @@ -511,6 +512,7 @@ static void free_block_bdev(struct zram was_set = test_and_clear_bit(blk_idx, zram->bitmap); WARN_ON_ONCE(!was_set); + atomic64_dec(&zram->stats.bd_count); } static void zram_page_end_io(struct bio *bio) @@ -668,6 +670,7 @@ static ssize_t writeback_store(struct de continue; } + atomic64_inc(&zram->stats.bd_writes); /* * We released zram_slot_lock so need to check if the slot was * changed. If there is freeing for the slot, we can catch it @@ -757,6 +760,7 @@ static int read_from_bdev_sync(struct zr static int read_from_bdev(struct zram *zram, struct bio_vec *bvec, unsigned long entry, struct bio *parent, bool sync) { + atomic64_inc(&zram->stats.bd_reads); if (sync) return read_from_bdev_sync(zram, bvec, entry, parent); else @@ -1013,6 +1017,25 @@ static ssize_t mm_stat_show(struct devic return ret; } +#ifdef CONFIG_ZRAM_WRITEBACK +static ssize_t bd_stat_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct zram *zram = dev_to_zram(dev); + ssize_t ret; + + down_read(&zram->init_lock); + ret = scnprintf(buf, PAGE_SIZE, + "%8llu %8llu %8llu\n", + (u64)atomic64_read(&zram->stats.bd_count), + (u64)atomic64_read(&zram->stats.bd_reads), + (u64)atomic64_read(&zram->stats.bd_writes)); + up_read(&zram->init_lock); + + return ret; +} +#endif + static ssize_t debug_stat_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -1033,6 +1056,9 @@ static ssize_t debug_stat_show(struct de static DEVICE_ATTR_RO(io_stat); static DEVICE_ATTR_RO(mm_stat); +#ifdef CONFIG_ZRAM_WRITEBACK +static DEVICE_ATTR_RO(bd_stat); +#endif static DEVICE_ATTR_RO(debug_stat); static void zram_meta_free(struct zram *zram, u64 disksize) @@ -1759,6 +1785,9 @@ static struct attribute *zram_disk_attrs #endif &dev_attr_io_stat.attr, &dev_attr_mm_stat.attr, +#ifdef CONFIG_ZRAM_WRITEBACK + &dev_attr_bd_stat.attr, +#endif &dev_attr_debug_stat.attr, NULL, }; --- a/drivers/block/zram/zram_drv.h~zram-add-bd_stat-statistics +++ a/drivers/block/zram/zram_drv.h @@ -82,6 +82,11 @@ struct zram_stats { atomic_long_t max_used_pages; /* no. of maximum pages stored */ atomic64_t writestall; /* no. of write slow paths */ atomic64_t miss_free; /* no. of missed free */ +#ifdef CONFIG_ZRAM_WRITEBACK + atomic64_t bd_count; /* no. of pages in backing device */ + atomic64_t bd_reads; /* no. of reads from backing device */ + atomic64_t bd_writes; /* no. of writes from backing device */ +#endif }; struct zram { _ Patches currently in -mm which might be from minchan(a)kernel.org are zram-fix-lockdep-warning-of-free-block-handling.patch zram-fix-double-free-backing-device.patch zram-refactoring-flags-and-writeback-stuff.patch zram-introduce-zram_idle-flag.patch zram-support-idle-huge-page-writeback.patch zram-add-bd_stat-statistics.patch zram-writeback-throttle.patch

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