- 30 Mar, 2022 6 commits
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Thomas Gleixner authored
Use the offset calculation to do the size calculation which avoids yet another series of CPUID instructions for each invocation. [ Fix the FP/SSE only case which missed to take the xstate header into account, as Reported-by: kernel test robot <oliver.sang@intel.com> ] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/87o81pgbp2.ffs@tglx
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Thomas Gleixner authored
The size calculation in __xstate_request_perm() fails to take supervisor states into account because the permission bitmap is only relevant for user states. Up to 5.17 this does not matter because there are no supervisor states supported, but the (re-)enabling of ENQCMD makes them available. Fixes: 7c1ef591 ("x86/cpufeatures: Re-enable ENQCMD") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220324134623.681768598@linutronix.de
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Thomas Gleixner authored
So far the cached fixed compacted offsets worked, but with (re-)enabling of ENQCMD this does no longer work with KVM fpstate. KVM does not have supervisor features enabled for the guest FPU, which means that KVM has then a different XSAVE area layout than the host FPU state. This in turn breaks the copy from/to UABI functions when invoked for a guest state. Remove the pre-calculated compacted offsets and calculate the offset of each component at runtime based on the XCOMP_BV field in the XSAVE header. The runtime overhead is not interesting because these copy from/to UABI functions are not used in critical fast paths. KVM uses them to save and restore FPU state during migration. The host uses them for ptrace and for the slow path of 32bit signal handling. Fixes: 7c1ef591 ("x86/cpufeatures: Re-enable ENQCMD") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220324134623.627636809@linutronix.de
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Thomas Gleixner authored
In preparation for runtime calculation of XSAVE offsets cache the feature flags for each XSTATE component during feature enumeration via CPUID(0xD). EDX has two relevant bits: 0 Supervisor component 1 Feature storage must be 64 byte aligned These bits are currently only evaluated during init, but the alignment bit must be cached to make runtime calculation of XSAVE offsets efficient. Cache the full EDX content and use it for the existing alignment and supervisor checks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220324134623.573656209@linutronix.de
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Thomas Gleixner authored
Reading XSTATE feature information from CPUID over and over does not make sense. The information has to be cached anyway, so it can be done early. Prepare for runtime calculation of XSTATE offsets and allow consolidation of the size calculation functions in a later step. Rename the function while at it as it does not setup any features. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220324134623.519411939@linutronix.de
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Thomas Gleixner authored
No users. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220324134623.465066249@linutronix.de
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- 29 Mar, 2022 2 commits
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Thomas Gleixner authored
fpu_copy_uabi_to_guest_fpstate() initializes the XCOMP_BV field in the XSAVE header. That's a leftover from the old KVM FPU buffer handling code. Since d69c1382 ("x86/kvm: Convert FPU handling to a single swap buffer") KVM uses the FPU core allocation code, which initializes the XCOMP_BV field already. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220324134623.408932232@linutronix.de
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Joerg Roedel authored
The io-specific memcpy/memset functions use string mmio accesses to do their work. Under SEV, the hypervisor can't emulate these instructions because they read/write directly from/to encrypted memory. KVM will inject a page fault exception into the guest when it is asked to emulate string mmio instructions for an SEV guest: BUG: unable to handle page fault for address: ffffc90000065068 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8000100000067 P4D 8000100000067 PUD 80001000fb067 PMD 80001000fc067 PTE 80000000fed40173 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc7 #3 As string mmio for an SEV guest can not be supported by the hypervisor, unroll the instructions for CC_ATTR_GUEST_UNROLL_STRING_IO enabled kernels. This issue appears when kernels are launched in recent libvirt-managed SEV virtual machines, because virt-install started to add a tpm-crb device to the guest by default and proactively because, raisins: https://github.com/virt-manager/virt-manager/commit/eb58c09f488b0633ed1eea012cd311e48864401e and as that commit says, the default adding of a TPM can be disabled with "virt-install ... --tpm none". The kernel driver for tpm-crb uses memcpy_to/from_io() functions to access MMIO memory, resulting in a page-fault injected by KVM and crashing the kernel at boot. [ bp: Massage and extend commit message. ] Fixes: d8aa7eea ('x86/mm: Add Secure Encrypted Virtualization (SEV) support') Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20220321093351.23976-1-joro@8bytes.org
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- 27 Mar, 2022 1 commit
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Ingo Molnar authored
- Use 'make savedefconfig' to refresh & regenerate the files - Add in KVM boot enablers - Enable the cgroup features most distros rely on [ fix bug found by Nathan Chancellor ] Acked-by: Nathan Chancellor <nathan@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/YjwsUT/6PkRPjnHE@gmail.com
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- 24 Mar, 2022 1 commit
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Borislav Petkov authored
To quote Linus: "EVERYBODY should have CONFIG_WERROR=y on at least x86-64 and other serious architectures, unless you have some completely random experimental (and broken) compiler. New compiler warnings are not acceptable." So this should make at least the most obvious and common ones not go unnoticed. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/YjsCpoRK7W4l6tSh@zn.tnic
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- 23 Mar, 2022 4 commits
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Chang S. Bae authored
Update the arch_prctl test to check the permission bitmap whether the requested feature is added as expected or not. Every non-dynamic feature that is enabled is permitted already for use. TILECFG is not dynamic feature. Ensure the bit is always on from ARCH_GET_XCOMP_PERM. Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20220129173647.27981-3-chang.seok.bae@intel.com
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Yang Zhong authored
ARCH_REQ_XCOMP_PERM is supposed to add the requested feature to the permission bitmap of thread_group_leader()->fpu. But the code overwrites the bitmap with the requested feature bit only rather than adding it. Fix the code to add the requested feature bit to the master bitmask. Fixes: db8268df ("x86/arch_prctl: Add controls for dynamic XSTATE components") Signed-off-by: Yang Zhong <yang.zhong@intel.com> Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Paolo Bonzini <bonzini@gnu.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220129173647.27981-2-chang.seok.bae@intel.com
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git://git.infradead.org/users/willy/pagecacheLinus Torvalds authored
Pull filesystem folio updates from Matthew Wilcox: "Primarily this series converts some of the address_space operations to take a folio instead of a page. Notably: - a_ops->is_partially_uptodate() takes a folio instead of a page and changes the type of the 'from' and 'count' arguments to make it obvious they're bytes. - a_ops->invalidatepage() becomes ->invalidate_folio() and has a similar type change. - a_ops->launder_page() becomes ->launder_folio() - a_ops->set_page_dirty() becomes ->dirty_folio() and adds the address_space as an argument. There are a couple of other misc changes up front that weren't worth separating into their own pull request" * tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache: (53 commits) fs: Remove aops ->set_page_dirty fb_defio: Use noop_dirty_folio() fs: Convert __set_page_dirty_no_writeback to noop_dirty_folio fs: Convert __set_page_dirty_buffers to block_dirty_folio nilfs: Convert nilfs_set_page_dirty() to nilfs_dirty_folio() mm: Convert swap_set_page_dirty() to swap_dirty_folio() ubifs: Convert ubifs_set_page_dirty to ubifs_dirty_folio f2fs: Convert f2fs_set_node_page_dirty to f2fs_dirty_node_folio f2fs: Convert f2fs_set_data_page_dirty to f2fs_dirty_data_folio f2fs: Convert f2fs_set_meta_page_dirty to f2fs_dirty_meta_folio afs: Convert afs_dir_set_page_dirty() to afs_dir_dirty_folio() btrfs: Convert extent_range_redirty_for_io() to use folios fs: Convert trivial uses of __set_page_dirty_nobuffers to filemap_dirty_folio btrfs: Convert from set_page_dirty to dirty_folio fscache: Convert fscache_set_page_dirty() to fscache_dirty_folio() fs: Add aops->dirty_folio fs: Remove aops->launder_page orangefs: Convert launder_page to launder_folio nfs: Convert from launder_page to launder_folio fuse: Convert from launder_page to launder_folio ...
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git://git.infradead.org/users/willy/pagecacheLinus Torvalds authored
Pull folio updates from Matthew Wilcox: - Rewrite how munlock works to massively reduce the contention on i_mmap_rwsem (Hugh Dickins): https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/ - Sort out the page refcount mess for ZONE_DEVICE pages (Christoph Hellwig): https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/ - Convert GUP to use folios and make pincount available for order-1 pages. (Matthew Wilcox) - Convert a few more truncation functions to use folios (Matthew Wilcox) - Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew Wilcox) - Convert rmap_walk to use folios (Matthew Wilcox) - Convert most of shrink_page_list() to use a folio (Matthew Wilcox) - Add support for creating large folios in readahead (Matthew Wilcox) * tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits) mm/damon: minor cleanup for damon_pa_young selftests/vm/transhuge-stress: Support file-backed PMD folios mm/filemap: Support VM_HUGEPAGE for file mappings mm/readahead: Switch to page_cache_ra_order mm/readahead: Align file mappings for non-DAX mm/readahead: Add large folio readahead mm: Support arbitrary THP sizes mm: Make large folios depend on THP mm: Fix READ_ONLY_THP warning mm/filemap: Allow large folios to be added to the page cache mm: Turn can_split_huge_page() into can_split_folio() mm/vmscan: Convert pageout() to take a folio mm/vmscan: Turn page_check_references() into folio_check_references() mm/vmscan: Account large folios correctly mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios mm/vmscan: Free non-shmem folios without splitting them mm/rmap: Constify the rmap_walk_control argument mm/rmap: Convert rmap_walk() to take a folio mm: Turn page_anon_vma() into folio_anon_vma() mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read() ...
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- 22 Mar, 2022 26 commits
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Linus Torvalds authored
Merge updates from Andrew Morton: - A few misc subsystems: kthread, scripts, ntfs, ocfs2, block, and vfs - Most the MM patches which precede the patches in Willy's tree: kasan, pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap, sparsemem, vmalloc, pagealloc, memory-failure, mlock, hugetlb, userfaultfd, vmscan, compaction, mempolicy, oom-kill, migration, thp, cma, autonuma, psi, ksm, page-poison, madvise, memory-hotplug, rmap, zswap, uaccess, ioremap, highmem, cleanups, kfence, hmm, and damon. * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (227 commits) mm/damon/sysfs: remove repeat container_of() in damon_sysfs_kdamond_release() Docs/ABI/testing: add DAMON sysfs interface ABI document Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface selftests/damon: add a test for DAMON sysfs interface mm/damon/sysfs: support DAMOS stats mm/damon/sysfs: support DAMOS watermarks mm/damon/sysfs: support schemes prioritization mm/damon/sysfs: support DAMOS quotas mm/damon/sysfs: support DAMON-based Operation Schemes mm/damon/sysfs: support the physical address space monitoring mm/damon/sysfs: link DAMON for virtual address spaces monitoring mm/damon: implement a minimal stub for sysfs-based DAMON interface mm/damon/core: add number of each enum type values mm/damon/core: allow non-exclusive DAMON start/stop Docs/damon: update outdated term 'regions update interval' Docs/vm/damon/design: update DAMON-Idle Page Tracking interference handling Docs/vm/damon: call low level monitoring primitives the operations mm/damon: remove unnecessary CONFIG_DAMON option mm/damon/paddr,vaddr: remove damon_{p,v}a_{target_valid,set_operations}() mm/damon/dbgfs-test: fix is_target_id() change ...
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Xin Hao authored
In damon_sysfs_kdamond_release(), we have use container_of() to get "kdamond" pointer, so there no need to get it once again. Link: https://lkml.kernel.org/r/20220303075314.22502-1-xhao@linux.alibaba.comSigned-off-by: Xin Hao <xhao@linux.alibaba.com> Reviewed-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit adds DAMON sysfs interface ABI document under Documentation/ABI/testing. Link: https://lkml.kernel.org/r/20220228081314.5770-14-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit adds detailed usage of DAMON sysfs interface in the admin-guide document for DAMON. Link: https://lkml.kernel.org/r/20220228081314.5770-13-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit adds a selftest for DAMON sysfs interface. It tests the functionality of 'nr' files and existence of files in each directory of the hierarchy. Link: https://lkml.kernel.org/r/20220228081314.5770-12-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON sysfs interface supports the DAMOS stats feature. Specifically, this commit adds 'stats' directory under each scheme directory, and update the contents of the files under the directory according to the latest monitoring results, when the user writes special keyword, 'update_schemes_stats' to the 'state' file of the kdamond. As a result, the files hierarchy becomes as below: /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ │ regions/nr_regions │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr_schemes │ │ │ │ │ │ 0/action │ │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max │ │ │ │ │ │ │ quotas/ms,sz,reset_interval_ms │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low │ │ │ │ │ │ │ stats/ <- NEW DIRECTORY │ │ │ │ │ │ │ │ nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Link: https://lkml.kernel.org/r/20220228081314.5770-11-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON sysfs interface supports the DAMOS watermarks feature. Specifically, this commit adds 'watermarks' directory under each scheme directory and makes kdamond 'state' file writing respects the contents in the directory. As a result, the files hierarchy becomes as below: /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ │ regions/nr_regions │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr_schemes │ │ │ │ │ │ 0/action │ │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max │ │ │ │ │ │ │ quotas/ms,sz,reset_interval_ms │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ │ watermarks/ <- NEW DIRECTORY │ │ │ │ │ │ │ │ metric,interval_us,high,mid,lo │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... [sj@kernel.org: fix out-of-bound array access for wmark_metric_strs[]] Link: https://lkml.kernel.org/r/20220301185619.2904-1-sj@kernel.org Link: https://lkml.kernel.org/r/20220228081314.5770-10-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Cc: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON sysfs interface supports the DAMOS' regions prioritization weights feature under quotas limitation. Specifically, this commit adds 'weights' directory under each scheme directory and makes kdamond 'state' file writing respects the contents in the directory. /sys/kernel/mm/damon/admin │ kdamonds/nr │ │ 0/state,pid │ │ │ contexts/nr │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr │ │ │ │ │ │ 0/pid │ │ │ │ │ │ │ regions/nr │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr │ │ │ │ │ │ 0/action │ │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max │ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms │ │ │ │ │ │ │ │ weights/ <- NEW DIRECTORY │ │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Link: https://lkml.kernel.org/r/20220228081314.5770-9-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON sysfs interface supports the DAMOS quotas feature. Specifically, this commit adds 'quotas' directory under each scheme directory and makes kdamond 'state' file writing respects the contents in the directory. As a result, the files hierarchy becomes as below: /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ │ regions/nr_regions │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr_schemes │ │ │ │ │ │ 0/action │ │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max │ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms <- NEW DIRECTORY │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Link: https://lkml.kernel.org/r/20220228081314.5770-8-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON sysfs interface supports the DAMON-based operation schemes (DAMOS) feature. Specifically, this commit adds 'schemes' directory under each context direcotry, and makes kdamond 'state' file writing respects the contents in the directory. Note that this commit doesn't support all features of DAMOS but only the target access pattern and action feature. Supports for quotas, prioritization, watermarks will follow. As a result, the files hierarchy becomes as below: /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ │ regions/nr_regions │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr_schemes <- NEW DIRECTORY │ │ │ │ │ │ 0/action │ │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Link: https://lkml.kernel.org/r/20220228081314.5770-7-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON sysfs interface supports the physical address space monitoring. Specifically, this commit adds support of the initial monitoring regions set feature by adding 'regions' directory under each target directory and makes context operations file to receive 'paddr' in addition to 'vaddr'. As a result, the files hierarchy becomes as below: /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ │ regions/nr_regions <- NEW DIRECTORY │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Link: https://lkml.kernel.org/r/20220228081314.5770-6-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit links the DAMON sysfs interface to DAMON so that users can control DAMON via the interface. In detail, this commit makes writing 'on' to 'state' file constructs DAMON contexts based on values that users have written to relevant sysfs files and start the context. It supports only virtual address spaces monitoring at the moment, though. The files hierarchy of DAMON sysfs interface after this commit is shown below. In the below figure, parents-children relations are represented with indentations, each directory is having ``/`` suffix, and files in each directory are separated by comma (","). /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... The usage is straightforward. Writing a number ('N') to each 'nr_*' file makes directories named '0' to 'N-1'. Users can construct DAMON contexts by writing proper values to the files in the straightforward manner and start each kdamond by writing 'on' to 'kdamonds/<N>/state'. Link: https://lkml.kernel.org/r/20220228081314.5770-5-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
DAMON's debugfs-based user interface served very well, so far. However, it unnecessarily depends on debugfs, while DAMON is not aimed to be used for only debugging. Also, the interface receives multiple values via one file. For example, schemes file receives 18 values separated by white spaces. As a result, it is ineffient, hard to be used, and difficult to be extended. Especially, keeping backward compatibility of user space tools is getting only challenging. It would be better to implement another reliable and flexible interface and deprecate the debugfs interface in long term. To this end, this commit implements a stub of a part of the new user interface of DAMON using sysfs. Specifically, this commit implements the sysfs control parts for virtual address space monitoring. More specifically, the idea of the new interface is, using directory hierarchies and making one file for one value. The hierarchy that this commit is introducing is as below. In the below figure, parents-children relations are represented with indentations, each directory is having ``/`` suffix, and files in each directory are separated by comma (","). /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Writing a number <N> to each 'nr' file makes directories of name <0> to <N-1> in the directory of the 'nr' file. That's all this commit does. Writing proper values to relevant files will construct the DAMON contexts, and writing a special keyword, 'on', to 'state' files for each kdamond will ask DAMON to start the constructed contexts. For a short example, using below commands for monitoring virtual address spaces of a given workload is imaginable: # cd /sys/kernel/mm/damon/admin/ # echo 1 > kdamonds/nr_kdamonds # echo 1 > kdamonds/0/contexts/nr_contexts # echo vaddr > kdamonds/0/contexts/0/operations # echo 1 > kdamonds/0/contexts/0/targets/nr_targets # echo $(pidof <workload>) > kdamonds/0/contexts/0/targets/0/pid_target # echo on > kdamonds/0/state Please note that this commit is implementing only the sysfs part stub as abovely mentioned. This commit doesn't implement the special keywords for 'state' files. Following commits will do that. [jiapeng.chong@linux.alibaba.com: fix missing error code in damon_sysfs_attrs_add_dirs()] Link: https://lkml.kernel.org/r/20220302111120.24984-1-jiapeng.chong@linux.alibaba.com Link: https://lkml.kernel.org/r/20220228081314.5770-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit declares the number of legal values for each DAMON enum types to make traversals of such DAMON enum types easy and safe. Link: https://lkml.kernel.org/r/20220228081314.5770-3-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
Patch series "Introduce DAMON sysfs interface", v3. Introduction ============ DAMON's debugfs-based user interface (DAMON_DBGFS) served very well, so far. However, it unnecessarily depends on debugfs, while DAMON is not aimed to be used for only debugging. Also, the interface receives multiple values via one file. For example, schemes file receives 18 values. As a result, it is inefficient, hard to be used, and difficult to be extended. Especially, keeping backward compatibility of user space tools is getting only challenging. It would be better to implement another reliable and flexible interface and deprecate DAMON_DBGFS in long term. For the reason, this patchset introduces a sysfs-based new user interface of DAMON. The idea of the new interface is, using directory hierarchies and having one dedicated file for each value. For a short example, users can do the virtual address monitoring via the interface as below: # cd /sys/kernel/mm/damon/admin/ # echo 1 > kdamonds/nr_kdamonds # echo 1 > kdamonds/0/contexts/nr_contexts # echo vaddr > kdamonds/0/contexts/0/operations # echo 1 > kdamonds/0/contexts/0/targets/nr_targets # echo $(pidof <workload>) > kdamonds/0/contexts/0/targets/0/pid_target # echo on > kdamonds/0/state A brief representation of the files hierarchy of DAMON sysfs interface is as below. Childs are represented with indentation, directories are having '/' suffix, and files in each directory are separated by comma. /sys/kernel/mm/damon/admin │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts │ │ │ │ 0/operations │ │ │ │ │ monitoring_attrs/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ targets/nr_targets │ │ │ │ │ │ 0/pid_target │ │ │ │ │ │ │ regions/nr_regions │ │ │ │ │ │ │ │ 0/start,end │ │ │ │ │ │ │ │ ... │ │ │ │ │ │ ... │ │ │ │ │ schemes/nr_schemes │ │ │ │ │ │ 0/action │ │ │ │ │ │ │ access_pattern/ │ │ │ │ │ │ │ │ sz/min,max │ │ │ │ │ │ │ │ nr_accesses/min,max │ │ │ │ │ │ │ │ age/min,max │ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms │ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil │ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low │ │ │ │ │ │ │ stats/nr_tried,sz_tried,nr_applied,sz_applied,qt_exceeds │ │ │ │ │ │ ... │ │ │ │ ... │ │ ... Detailed usage of the files will be described in the final Documentation patch of this patchset. Main Difference Between DAMON_DBGFS and DAMON_SYSFS --------------------------------------------------- At the moment, DAMON_DBGFS and DAMON_SYSFS provides same features. One important difference between them is their exclusiveness. DAMON_DBGFS works in an exclusive manner, so that no DAMON worker thread (kdamond) in the system can run concurrently and interfere somehow. For the reason, DAMON_DBGFS asks users to construct all monitoring contexts and start them at once. It's not a big problem but makes the operation a little bit complex and unflexible. For more flexible usage, DAMON_SYSFS moves the responsibility of preventing any possible interference to the admins and work in a non-exclusive manner. That is, users can configure and start contexts one by one. Note that DAMON respects both exclusive groups and non-exclusive groups of contexts, in a manner similar to that of reader-writer locks. That is, if any exclusive monitoring contexts (e.g., contexts that started via DAMON_DBGFS) are running, DAMON_SYSFS does not start new contexts, and vice versa. Future Plan of DAMON_DBGFS Deprecation ====================================== Once this patchset is merged, DAMON_DBGFS development will be frozen. That is, we will maintain it to work as is now so that no users will be break. But, it will not be extended to provide any new feature of DAMON. The support will be continued only until next LTS release. After that, we will drop DAMON_DBGFS. User-space Tooling Compatibility -------------------------------- As DAMON_SYSFS provides all features of DAMON_DBGFS, all user space tooling can move to DAMON_SYSFS. As we will continue supporting DAMON_DBGFS until next LTS kernel release, user space tools would have enough time to move to DAMON_SYSFS. The official user space tool, damo[1], is already supporting both DAMON_SYSFS and DAMON_DBGFS. Both correctness tests[2] and performance tests[3] of DAMON using DAMON_SYSFS also passed. [1] https://github.com/awslabs/damo [2] https://github.com/awslabs/damon-tests/tree/master/corr [3] https://github.com/awslabs/damon-tests/tree/master/perf Sequence of Patches =================== First two patches (patches 1-2) make core changes for DAMON_SYSFS. The first one (patch 1) allows non-exclusive DAMON contexts so that DAMON_SYSFS can work in non-exclusive mode, while the second one (patch 2) adds size of DAMON enum types so that DAMON API users can safely iterate the enums. Third patch (patch 3) implements basic sysfs stub for virtual address spaces monitoring. Note that this implements only sysfs files and DAMON is not linked. Fourth patch (patch 4) links the DAMON_SYSFS to DAMON so that users can control DAMON using the sysfs files. Following six patches (patches 5-10) implements other DAMON features that DAMON_DBGFS supports one by one (physical address space monitoring, DAMON-based operation schemes, schemes quotas, schemes prioritization weights, schemes watermarks, and schemes stats). Following patch (patch 11) adds a simple selftest for DAMON_SYSFS, and the final one (patch 12) documents DAMON_SYSFS. This patch (of 13): To avoid interference between DAMON contexts monitoring overlapping memory regions, damon_start() works in an exclusive manner. That is, damon_start() does nothing bug fails if any context that started by another instance of the function is still running. This makes its usage a little bit restrictive. However, admins could aware each DAMON usage and address such interferences on their own in some cases. This commit hence implements non-exclusive mode of the function and allows the callers to select the mode. Note that the exclusive groups and non-exclusive groups of contexts will respect each other in a manner similar to that of reader-writer locks. Therefore, this commit will not cause any behavioral change to the exclusive groups. Link: https://lkml.kernel.org/r/20220228081314.5770-1-sj@kernel.org Link: https://lkml.kernel.org/r/20220228081314.5770-2-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
Before DAMON is merged in the mainline, the concept of 'regions update interval' has generalized to be used as the time interval for update of any monitoring operations related data structure, but the document has not updated properly. This commit updates the document for better consistency. Link: https://lkml.kernel.org/r/20220222170100.17068-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
In DAMON's early development stage before it be merged in the mainline, it was first designed to work exclusively with Idle page tracking to avoid any interference between each other. Later, but still before be merged in the mainline, because Idle page tracking is fully under the control of sysadmins, we made the resolving of conflict as the responsibility of sysadmins. The document is not updated for the change, though. This commit updates the document for that. Link: https://lkml.kernel.org/r/20220222170100.17068-3-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
Patch series "Docs/damon: Update documents for better consistency". Some of DAMON document are not properly updated for latest version. This patchset updates such parts. This patch (of 3): DAMON code calls the low level monitoring primitives implementations the monitoring operations. The documentation would have no problem at still calling those primitives implementation because there is no real difference in the concepts, but making it more consistent with the code would make it better. This commit therefore convert sentences in the doc specifically pointing the implementations of the primitives to call it monitoring operations. Link: https://lkml.kernel.org/r/20220222170100.17068-1-sj@kernel.org Link: https://lkml.kernel.org/r/20220222170100.17068-2-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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tangmeng authored
In mm/Makefile has: obj-$(CONFIG_DAMON) += damon/ So that we don't need 'obj-$(CONFIG_DAMON) :=' in mm/damon/Makefile, delete it from mm/damon/Makefile. Link: https://lkml.kernel.org/r/20220221065255.19991-1-tangmeng@uniontech.comSigned-off-by: tangmeng <tangmeng@uniontech.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
Because DAMON debugfs interface and DAMON-based proactive reclaim are now using monitoring operations via registration mechanism, damon_{p,v}a_{target_valid,set_operations}() functions have no user. This commit clean them up. Link: https://lkml.kernel.org/r/20220215184603.1479-9-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
DAMON kunit tests for DAMON debugfs interface fails because it still assumes setting empty monitoring operations makes DAMON debugfs interface believe the target of the context don't have pid. This commit fixes the kunit test fails by explicitly setting the context's monitoring operations with the operations for the physical address space, which let debugfs knows the target will not have pid. Link: https://lkml.kernel.org/r/20220215184603.1479-8-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
DAMON debugfs interface depends on monitoring operations for virtual address spaces because it knows if the target has pid or not by seeing if the context is configured to use one of the virtual address space monitoring operation functions. We can replace that check with 'enum damon_ops_id' now, to make it independent. This commit makes the change. Link: https://lkml.kernel.org/r/20220215184603.1479-7-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON debugfs interface to select the registered monitoring operations for the physical address space or virtual address spaces depending on user requests instead of setting it on its own. Note that DAMON debugfs interface is still dependent to DAMON_VADDR with this change, because it is also using its symbol, 'damon_va_target_valid'. Link: https://lkml.kernel.org/r/20220215184603.1479-6-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes DAMON_RECLAIM to select the registered monitoring operations for the physical address space instead of setting it on its own. This allows DAMON_RECLAIM be independent of DAMON_PADDR, but leave the dependency as is, because it's the only one monitoring operations it use, and therefore it makes no sense to build DAMON_RECLAIM without DAMON_PADDR. Link: https://lkml.kernel.org/r/20220215184603.1479-5-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
This commit makes the monitoring operations for the physical address space and virtual address spaces register themselves to DAMON in the subsys_initcall step. Later, in-kernel DAMON user code can use them via damon_select_ops() without have to unnecessarily depend on all possible monitoring operations implementations. Link: https://lkml.kernel.org/r/20220215184603.1479-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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SeongJae Park authored
In-kernel DAMON user code like DAMON debugfs interface should set 'struct damon_operations' of its 'struct damon_ctx' on its own. Therefore, the client code should depend on all supporting monitoring operations implementations that it could use. For example, DAMON debugfs interface depends on both vaddr and paddr, while some of the users are not always interested in both. To minimize such unnecessary dependencies, this commit makes the monitoring operations can be registered by implementing code and then dynamically selected by the user code without build-time dependency. Link: https://lkml.kernel.org/r/20220215184603.1479-3-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Xin Hao <xhao@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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