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* mm: avoid setting up anonymous pages into file mappingKirill A. Shutemov2015-07-091-7/+13
| | | | | | | | | | | | | | | | | | | | | | Reading page fault handler code I've noticed that under right circumstances kernel would map anonymous pages into file mappings: if the VMA doesn't have vm_ops->fault() and the VMA wasn't fully populated on ->mmap(), kernel would handle page fault to not populated pte with do_anonymous_page(). Let's change page fault handler to use do_anonymous_page() only on anonymous VMA (->vm_ops == NULL) and make sure that the VMA is not shared. For file mappings without vm_ops->fault() or shred VMA without vm_ops, page fault on pte_none() entry would lead to SIGBUS. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Willy Tarreau <w@1wt.eu> Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2015-07-053-3/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
| * fs: Rename file_remove_suid() to file_remove_privs()Jan Kara2015-06-241-1/+1
| | | | | | | | | | | | | | | | | | | | file_remove_suid() is a misnomer since it removes also file capabilities stored in xattrs and sets S_NOSEC flag. Also should_remove_suid() tells something else than whether file_remove_suid() call is necessary which leads to bugs. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: add seq_file_path() helperMiklos Szeredi2015-06-241-1/+1
| | | | | | | | | | | | | | | | | | | | Turn seq_path(..., &file->f_path, ...); into seq_file_path(..., file, ...); Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: add file_path() helperMiklos Szeredi2015-06-241-1/+1
| | | | | | | | | | | | | | | | | | | | Turn d_path(&file->f_path, ...); into file_path(file, ...); Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds2015-07-031-47/+62
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block fixes from Jens Axboe: "Mainly sending this off now for the writeback fixes, since they fix a real regression introduced with the cgroup writeback changes. The NVMe fix could wait for next pull for this series, but it's simple enough that we might as well include it. This contains: - two cgroup writeback fixes from Tejun, fixing a user reported issue with luks crypt devices hanging when being closed. - NVMe error cleanup fix from Jon Derrick, fixing a case where we'd attempt to free an unregistered IRQ" * 'for-linus' of git://git.kernel.dk/linux-block: NVMe: Fix irq freeing when queue_request_irq fails writeback: don't drain bdi_writeback_congested on bdi destruction writeback: don't embed root bdi_writeback_congested in bdi_writeback
| * | writeback: don't drain bdi_writeback_congested on bdi destructionTejun Heo2015-07-021-6/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 52ebea749aae ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks") made bdi (backing_dev_info) host per-cgroup wb's (bdi_writeback's). As the congested state needs to be per-wb and referenced from blkcg side and multiple wbs, the patch made all non-root cong's (bdi_writeback_congested's) reference counted and indexed on bdi. When a bdi is destroyed, cgwb_bdi_destroy() tries to drain all non-root cong's; however, this can hang indefinitely because wb's can also be referenced from blkcg_gq's which are destroyed after bdi destruction is complete. This patch fixes the bug by updating bdi destruction to not wait for cong's to drain. A cong is unlinked from bdi->cgwb_congested_tree on bdi destuction regardless of its reference count as the bdi may go away any point after destruction. wb_congested_put() checks whether the cong is already unlinked on release. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jon Christopherson <jon@jons.org> Link: https://bugzilla.kernel.org/show_bug.cgi?id=100681 Fixes: 52ebea749aae ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks") Tested-by: Jon Christopherson <jon@jons.org> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | writeback: don't embed root bdi_writeback_congested in bdi_writebackTejun Heo2015-07-021-41/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 52ebea749aae ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks") made bdi (backing_dev_info) host per-cgroup wb's (bdi_writeback's). As the congested state needs to be per-wb and referenced from blkcg side and multiple wbs, the patch made all non-root cong's (bdi_writeback_congested's) reference counted and indexed on bdi. When a bdi is destroyed, cgwb_bdi_destroy() tries to drain all non-root cong's; however, this can hang indefinitely because wb's can also be referenced from blkcg_gq's which are destroyed after bdi destruction is complete. To fix the bug, bdi destruction will be updated to not wait for cong's to drain, which naturally means that cong's may outlive the associated bdi. This is fine for non-root cong's but is problematic for the root cong's which are embedded in their bdi's as they may end up getting dereferenced after the containing bdi's are freed. This patch makes root cong's behave the same as non-root cong's. They are no longer embedded in their bdi's but allocated separately during bdi initialization, indexed and reference counted the same way. * As cong handling is the same for all wb's, wb->congested initialization is moved into wb_init(). * When !CONFIG_CGROUP_WRITEBACK, there was no indexing or refcnting. bdi->wb_congested is now a pointer pointing to the root cong allocated during bdi init and minimal refcnting operations are implemented. * The above makes root wb init paths diverge depending on CONFIG_CGROUP_WRITEBACK. root wb init is moved to cgwb_bdi_init(). This patch in itself shouldn't cause any consequential behavior differences but prepares for the actual fix. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jon Christopherson <jon@jons.org> Link: https://bugzilla.kernel.org/show_bug.cgi?id=100681 Tested-by: Jon Christopherson <jon@jons.org> Added <linux/slab.h> include to backing-dev.h for kfree() definition. Signed-off-by: Jens Axboe <axboe@fb.com>
* | | Merge tag 'module_init-alternate_initcall-v4.1-rc8' of ↵Linus Torvalds2015-07-022-3/+3
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux Pull module_init replacement part two from Paul Gortmaker: "Replace module_init with appropriate alternate initcall in non modules. This series converts non-modular code that is using the module_init() call to hook itself into the system to instead use one of our alternate priority initcalls. Unlike the previous series that used device_initcall and hence was a runtime no-op, these commits change to one of the alternate initcalls, because (a) we have them and (b) it seems like the right thing to do. For example, it would seem logical to use arch_initcall for arch specific setup code and fs_initcall for filesystem setup code. This does mean however, that changes in the init ordering will be taking place, and so there is a small risk that some kind of implicit init ordering issue may lie uncovered. But I think it is still better to give these ones sensible priorities than to just assign them all to device_initcall in order to exactly preserve the old ordering. Thad said, we have already made similar changes in core kernel code in commit c96d6660dc65 ("kernel: audit/fix non-modular users of module_init in core code") without any regressions reported, so this type of change isn't without precedent. It has also got the same local testing and linux-next coverage as all the other pull requests that I'm sending for this merge window have got. Once again, there is an unused module_exit function removal that shows up as an outlier upon casual inspection of the diffstat" * tag 'module_init-alternate_initcall-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: x86: perf_event_intel_pt.c: use arch_initcall to hook in enabling x86: perf_event_intel_bts.c: use arch_initcall to hook in enabling mm/page_owner.c: use late_initcall to hook in enabling lib/list_sort: use late_initcall to hook in self tests arm: use subsys_initcall in non-modular pl320 IPC code powerpc: don't use module_init for non-modular core hugetlb code powerpc: use subsys_initcall for Freescale Local Bus x86: don't use module_init for non-modular core bootflag code netfilter: don't use module_init/exit in core IPV4 code fs/notify: don't use module_init for non-modular inotify_user code mm: replace module_init usages with subsys_initcall in nommu.c
| * | mm/page_owner.c: use late_initcall to hook in enablingPaul Gortmaker2015-06-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This was using module_init, but there is no way this code can be modular. In the non-modular case, a module_init becomes a device_initcall, but this really isn't a device. So we should choose a more appropriate initcall bucket to put it in. In order of execution, our close choices are: fs_initcall(fn) rootfs_initcall(fn) device_initcall(fn) late_initcall(fn) ..and since the initcall here goes after debugfs, we really should be post-rootfs, which means late_initcall makes the most sense here. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
| * | mm: replace module_init usages with subsys_initcall in nommu.cPaul Gortmaker2015-06-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Compiling some arm/m68k configs with "# CONFIG_MMU is not set" reveals two more instances of module_init being used for code that can't possibly be modular, as CONFIG_MMU is either on or off. We replace them with subsys_initcall as per what was done in other mmu-enabled code. Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of subsys_initcall (which makes sense for these files) will thus change this registration from level 6-device to level 4-subsys (i.e. slightly earlier). One might think that core_initcall (l2) or postcore_initcall (l3) would be more appropriate for anything in mm/ but if we look at the actual init functions themselves, we see they are just sysctl setup stuff, and hence the choice of subsys_initcall (l4) seems reasonable. At the same time it minimizes the risk of changing the priority too drastically all at once. We can adjust further in the future. Also, a couple instances of missing ";" at EOL are fixed. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* | | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2015-07-027-81/+453
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge third patchbomb from Andrew Morton: - the rest of MM - scripts/gdb updates - ipc/ updates - lib/ updates - MAINTAINERS updates - various other misc things * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (67 commits) genalloc: rename of_get_named_gen_pool() to of_gen_pool_get() genalloc: rename dev_get_gen_pool() to gen_pool_get() x86: opt into HAVE_COPY_THREAD_TLS, for both 32-bit and 64-bit MAINTAINERS: add zpool MAINTAINERS: BCACHE: Kent Overstreet has changed email address MAINTAINERS: move Jens Osterkamp to CREDITS MAINTAINERS: remove unused nbd.h pattern MAINTAINERS: update brcm gpio filename pattern MAINTAINERS: update brcm dts pattern MAINTAINERS: update sound soc intel patterns MAINTAINERS: remove website for paride MAINTAINERS: update Emulex ocrdma email addresses bcache: use kvfree() in various places libcxgbi: use kvfree() in cxgbi_free_big_mem() target: use kvfree() in session alloc and free IB/ehca: use kvfree() in ipz_queue_{cd}tor() drm/nouveau/gem: use kvfree() in u_free() drm: use kvfree() in drm_free_large() cxgb4: use kvfree() in t4_free_mem() cxgb3: use kvfree() in cxgb_free_mem() ...
| * | | mm: meminit: finish initialisation of struct pages before basic setupMel Gorman2015-07-013-37/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Waiman Long reported that 24TB machines hit OOM during basic setup when struct page initialisation was deferred. One approach is to initialise memory on demand but it interferes with page allocator paths. This patch creates dedicated threads to initialise memory before basic setup. It then blocks on a rw_semaphore until completion as a wait_queue and counter is overkill. This may be slower to boot but it's simplier overall and also gets rid of a section mangling which existed so kswapd could do the initialisation. [akpm@linux-foundation.org: include rwsem.h, use DECLARE_RWSEM, fix comment, remove unneeded cast] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Waiman Long <waiman.long@hp.com Cc: Nathan Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Scott Norton <scott.norton@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: remove mminit_verify_page_linksMel Gorman2015-07-013-17/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mminit_verify_page_links() is an extremely paranoid check that was introduced when memory initialisation was being heavily reworked. Profiles indicated that up to 10% of parallel memory initialisation was spent on checking this for every page. The cost could be reduced but in practice this check only found problems very early during the initialisation rewrite and has found nothing since. This patch removes an expensive unnecessary check. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: reduce number of times pageblocks are set during struct page initMel Gorman2015-07-011-22/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During parallel sturct page initialisation, ranges are checked for every PFN unnecessarily which increases boot times. This patch alters when the ranges are checked. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: free pages in large chunks where possibleMel Gorman2015-07-011-6/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Parallel struct page frees pages one at a time. Try free pages as single large pages where possible. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: minimise number of pfn->page lookups during initialisationMel Gorman2015-07-011-5/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Deferred struct page initialisation is using pfn_to_page() on every PFN unnecessarily. This patch minimises the number of lookups and scheduler checks. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: initialise remaining struct pages in parallel with kswapdMel Gorman2015-07-014-6/+130
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Only a subset of struct pages are initialised at the moment. When this patch is applied kswapd initialise the remaining struct pages in parallel. This should boot faster by spreading the work to multiple CPUs and initialising data that is local to the CPU. The user-visible effect on large machines is that free memory will appear to rapidly increase early in the lifetime of the system until kswapd reports that all memory is initialised in the kernel log. Once initialised there should be no other user-visibile effects. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: initialise a subset of struct pages if ↵Mel Gorman2015-07-013-3/+111
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CONFIG_DEFERRED_STRUCT_PAGE_INIT is set This patch initalises all low memory struct pages and 2G of the highest zone on each node during memory initialisation if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set. That config option cannot be set but will be available in a later patch. Parallel initialisation of struct page depends on some features from memory hotplug and it is necessary to alter alter section annotations. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: inline some helper functionsMel Gorman2015-07-011-37/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | early_pfn_in_nid() and meminit_pfn_in_nid() are small functions that are unnecessarily visible outside memory initialisation. As well as unnecessary visibility, it's unnecessary function call overhead when initialising pages. This patch moves the helpers inline. [akpm@linux-foundation.org: fix build] [mhocko@suse.cz: fix build] Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: make __early_pfn_to_nid SMP-safe and introduce meminit_pfn_in_nidMel Gorman2015-07-011-15/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __early_pfn_to_nid() use static variables to cache recent lookups as memblock lookups are very expensive but it assumes that memory initialisation is single-threaded. Parallel initialisation of struct pages will break that assumption so this patch makes __early_pfn_to_nid() SMP-safe by requiring the caller to cache recent search information. early_pfn_to_nid() keeps the same interface but is only safe to use early in boot due to the use of a global static variable. meminit_pfn_in_nid() is an SMP-safe version that callers must maintain their own state for. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: page_alloc: pass PFN to __free_pages_bootmemMel Gorman2015-07-015-11/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __free_pages_bootmem prepares a page for release to the buddy allocator and assumes that the struct page is initialised. Parallel initialisation of struct pages defers initialisation and __free_pages_bootmem can be called for struct pages that cannot yet map struct page to PFN. This patch passes PFN to __free_pages_bootmem with no other functional change. Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Nate Zimmer <nzimmer@sgi.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: only set page reserved in the memblock regionNathan Zimmer2015-07-012-1/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently each page struct is set as reserved upon initialization. This patch leaves the reserved bit clear and only sets the reserved bit when it is known the memory was allocated by the bootmem allocator. This makes it easier to distinguish between uninitialised struct pages and reserved struct pages in later patches. Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Nathan Zimmer <nzimmer@sgi.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm: meminit: move page initialization into a separate functionRobin Holt2015-07-011-33/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, memmap_init_zone() has all the smarts for initializing a single page. A subset of this is required for parallel page initialisation and so this patch breaks up the monolithic function in preparation. Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Nathan Zimmer <nzimmer@sgi.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | memblock: introduce a for_each_reserved_mem_region iteratorRobin Holt2015-07-011-0/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Struct page initialisation had been identified as one of the reasons why large machines take a long time to boot. Patches were posted a long time ago to defer initialisation until they were first used. This was rejected on the grounds it should not be necessary to hurt the fast paths. This series reuses much of the work from that time but defers the initialisation of memory to kswapd so that one thread per node initialises memory local to that node. After applying the series and setting the appropriate Kconfig variable I see this in the boot log on a 64G machine [ 7.383764] kswapd 0 initialised deferred memory in 188ms [ 7.404253] kswapd 1 initialised deferred memory in 208ms [ 7.411044] kswapd 3 initialised deferred memory in 216ms [ 7.411551] kswapd 2 initialised deferred memory in 216ms On a 1TB machine, I see [ 8.406511] kswapd 3 initialised deferred memory in 1116ms [ 8.428518] kswapd 1 initialised deferred memory in 1140ms [ 8.435977] kswapd 0 initialised deferred memory in 1148ms [ 8.437416] kswapd 2 initialised deferred memory in 1148ms Once booted the machine appears to work as normal. Boot times were measured from the time shutdown was called until ssh was available again. In the 64G case, the boot time savings are negligible. On the 1TB machine, the savings were 16 seconds. Nate Zimmer said: : On an older 8 TB box with lots and lots of cpus the boot time, as : measure from grub to login prompt, the boot time improved from 1484 : seconds to exactly 1000 seconds. Waiman Long said: : I ran a bootup timing test on a 12-TB 16-socket IvyBridge-EX system. From : grub menu to ssh login, the bootup time was 453s before the patch and 265s : after the patch - a saving of 188s (42%). Daniel Blueman said: : On a 7TB, 1728-core NumaConnect system with 108 NUMA nodes, we're seeing : stock 4.0 boot in 7136s. This drops to 2159s, or a 70% reduction with : this patchset. Non-temporal PMD init (https://lkml.org/lkml/2015/4/23/350) : drops this to 1045s. This patch (of 13): As part of initializing struct page's in 2MiB chunks, we noticed that at the end of free_all_bootmem(), there was nothing which had forced the reserved/allocated 4KiB pages to be initialized. This helper function will be used for that expansion. Signed-off-by: Robin Holt <holt@sgi.com> Signed-off-by: Nate Zimmer <nzimmer@sgi.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Nate Zimmer <nzimmer@sgi.com> Tested-by: Waiman Long <waiman.long@hp.com> Tested-by: Daniel J Blueman <daniel@numascale.com> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Robin Holt <robinmholt@gmail.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Waiman Long <waiman.long@hp.com> Cc: Scott Norton <scott.norton@hp.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | Add __init attribute to new_kmalloc_cacheChristoph Lameter2015-07-011-1/+1
|/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid the warning: WARNING: mm/built-in.o(.text.unlikely+0xc22): Section mismatch in reference from the function .new_kmalloc_cache() to the variable .init.rodata:kmalloc_info The function .new_kmalloc_cache() references the variable __initconst kmalloc_info. Signed-off-by: Christoph Lameter <cl@linux.com> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Fix kmalloc slab creation sequenceChristoph Lameter2015-06-291-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch restores the slab creation sequence that was broken by commit 4066c33d0308f8 and also reverts the portions that introduced the KMALLOC_LOOP_XXX macros. Those can never really work since the slab creation is much more complex than just going from a minimum to a maximum number. The latest upstream kernel boots cleanly on my machine with a 64 bit x86 configuration under KVM using either SLAB or SLUB. Fixes: 4066c33d0308f8 ("support the slub_debug boot option") Reported-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge tag 'trace-v4.2' of ↵Linus Torvalds2015-06-261-1/+1
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "This patch series contains several clean ups and even a new trace clock "monitonic raw". Also some enhancements to make the ring buffer even faster. But the biggest and most noticeable change is the renaming of the ftrace* files, structures and variables that have to deal with trace events. Over the years I've had several developers tell me about their confusion with what ftrace is compared to events. Technically, "ftrace" is the infrastructure to do the function hooks, which include tracing and also helps with live kernel patching. But the trace events are a separate entity altogether, and the files that affect the trace events should not be named "ftrace". These include: include/trace/ftrace.h -> include/trace/trace_events.h include/linux/ftrace_event.h -> include/linux/trace_events.h Also, functions that are specific for trace events have also been renamed: ftrace_print_*() -> trace_print_*() (un)register_ftrace_event() -> (un)register_trace_event() ftrace_event_name() -> trace_event_name() ftrace_trigger_soft_disabled() -> trace_trigger_soft_disabled() ftrace_define_fields_##call() -> trace_define_fields_##call() ftrace_get_offsets_##call() -> trace_get_offsets_##call() Structures have been renamed: ftrace_event_file -> trace_event_file ftrace_event_{call,class} -> trace_event_{call,class} ftrace_event_buffer -> trace_event_buffer ftrace_subsystem_dir -> trace_subsystem_dir ftrace_event_raw_##call -> trace_event_raw_##call ftrace_event_data_offset_##call-> trace_event_data_offset_##call ftrace_event_type_funcs_##call -> trace_event_type_funcs_##call And a few various variables and flags have also been updated. This has been sitting in linux-next for some time, and I have not heard a single complaint about this rename breaking anything. Mostly because these functions, variables and structures are mostly internal to the tracing system and are seldom (if ever) used by anything external to that" * tag 'trace-v4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits) ring_buffer: Allow to exit the ring buffer benchmark immediately ring-buffer-benchmark: Fix the wrong type ring-buffer-benchmark: Fix the wrong param in module_param ring-buffer: Add enum names for the context levels ring-buffer: Remove useless unused tracing_off_permanent() ring-buffer: Give NMIs a chance to lock the reader_lock ring-buffer: Add trace_recursive checks to ring_buffer_write() ring-buffer: Allways do the trace_recursive checks ring-buffer: Move recursive check to per_cpu descriptor ring-buffer: Add unlikelys to make fast path the default tracing: Rename ftrace_get_offsets_##call() to trace_event_get_offsets_##call() tracing: Rename ftrace_define_fields_##call() to trace_event_define_fields_##call() tracing: Rename ftrace_event_type_funcs_##call to trace_event_type_funcs_##call tracing: Rename ftrace_data_offset_##call to trace_event_data_offset_##call tracing: Rename ftrace_raw_##call event structures to trace_event_raw_##call tracing: Rename ftrace_trigger_soft_disabled() to trace_trigger_soft_disabled() tracing: Rename FTRACE_EVENT_FL_* flags to EVENT_FILE_FL_* tracing: Rename struct ftrace_subsystem_dir to trace_subsystem_dir tracing: Rename ftrace_event_name() to trace_event_name() tracing: Rename FTRACE_MAX_EVENT to TRACE_EVENT_TYPE_MAX ...
| * | | tracing: Rename ftrace_event.h to trace_events.hSteven Rostedt (Red Hat)2015-05-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The term "ftrace" is really the infrastructure of the function hooks, and not the trace events. Rename ftrace_event.h to trace_events.h to represent the trace_event infrastructure and decouple the term ftrace from it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2015-06-266-58/+30
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge second patchbomb from Andrew Morton: - most of the rest of MM - lots of misc things - procfs updates - printk feature work - updates to get_maintainer, MAINTAINERS, checkpatch - lib/ updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (96 commits) exit,stats: /* obey this comment */ coredump: add __printf attribute to cn_*printf functions coredump: use from_kuid/kgid when formatting corename fs/reiserfs: remove unneeded cast NILFS2: support NFSv2 export fs/befs/btree.c: remove unneeded initializations fs/minix: remove unneeded cast init/do_mounts.c: add create_dev() failure log kasan: remove duplicate definition of the macro KASAN_FREE_PAGE fs/efs: femove unneeded cast checkpatch: emit "NOTE: <types>" message only once after multiple files checkpatch: emit an error when there's a diff in a changelog checkpatch: validate MODULE_LICENSE content checkpatch: add multi-line handling for PREFER_ETHER_ADDR_COPY checkpatch: suggest using eth_zero_addr() and eth_broadcast_addr() checkpatch: fix processing of MEMSET issues checkpatch: suggest using ether_addr_equal*() checkpatch: avoid NOT_UNIFIED_DIFF errors on cover-letter.patch files checkpatch: remove local from codespell path checkpatch: add --showfile to allow input via pipe to show filenames ...
| * | | | kasan: remove duplicate definition of the macro KASAN_FREE_PAGEWang Long2015-06-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove duplicate definition of the macro KASAN_FREE_PAGE in mm/kasan/kasan.h Signed-off-by: Wang Long <long.wanglong@huawei.com> Acked-by: Andrey Ryabinin <a.ryabinin@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | zpool: remove zpool_evict()Dan Streetman2015-06-263-33/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove zpool_evict() helper function. As zbud is currently the only zpool implementation that supports eviction, add zpool and zpool_ops references to struct zbud_pool and directly call zpool_ops->evict(zpool, handle) on eviction. Currently zpool provides the zpool_evict helper which locks the zpool list lock and searches through all pools to find the specific one matching the caller, and call the corresponding zpool_ops->evict function. However, this is unnecessary, as the zbud pool can simply keep a reference to the zpool that created it, as well as the zpool_ops, and directly call the zpool_ops->evict function, when it needs to evict a page. This avoids a spinlock and list search in zpool for each eviction. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Cc: Seth Jennings <sjennings@variantweb.net> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | zpool: change pr_info to pr_debugDan Streetman2015-06-261-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change the pr_info() calls to pr_debug(). There's no need for the extra verbosity in the log. Also change the msg formats to be consistent. Signed-off-by: Dan Streetman <ddstreet@ieee.org> Cc: Kees Cook <keescook@chromium.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Ganesh Mahendran <opensource.ganesh@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | zswap: runtime enable/disableDan Streetman2015-06-261-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change the "enabled" parameter to be configurable at runtime. Remove the enabled check from init(), and move it to the frontswap store() function; when enabled, pages will be stored, and when disabled, pages won't be stored. This is almost identical to Seth's patch from 2 years ago: http://lkml.iu.edu/hypermail/linux/kernel/1307.2/04289.html [akpm@linux-foundation.org: tweak documentation] Signed-off-by: Dan Streetman <ddstreet@ieee.org> Suggested-by: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | zsmalloc: remove obsolete ZSMALLOC_DEBUGMarcin Jabrzyk2015-06-261-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The DEBUG define in zsmalloc is useless, there is no usage of it at all. Signed-off-by: Marcin Jabrzyk <m.jabrzyk@samsung.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | | mm/hugetlb: remove unused arch hook prepare/release_hugepageDominik Dingel2015-06-261-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With s390 dropping support for emulated hugepages, the last user of arch_prepare_hugepage and arch_release_hugepage is gone. Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | | Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-blockLinus Torvalds2015-06-2610-647/+1579
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull cgroup writeback support from Jens Axboe: "This is the big pull request for adding cgroup writeback support. This code has been in development for a long time, and it has been simmering in for-next for a good chunk of this cycle too. This is one of those problems that has been talked about for at least half a decade, finally there's a solution and code to go with it. Also see last weeks writeup on LWN: http://lwn.net/Articles/648292/" * 'for-4.2/writeback' of git://git.kernel.dk/linux-block: (85 commits) writeback, blkio: add documentation for cgroup writeback support vfs, writeback: replace FS_CGROUP_WRITEBACK with SB_I_CGROUPWB writeback: do foreign inode detection iff cgroup writeback is enabled v9fs: fix error handling in v9fs_session_init() bdi: fix wrong error return value in cgwb_create() buffer: remove unusued 'ret' variable writeback: disassociate inodes from dying bdi_writebacks writeback: implement foreign cgroup inode bdi_writeback switching writeback: add lockdep annotation to inode_to_wb() writeback: use unlocked_inode_to_wb transaction in inode_congested() writeback: implement unlocked_inode_to_wb transaction and use it for stat updates writeback: implement [locked_]inode_to_wb_and_lock_list() writeback: implement foreign cgroup inode detection writeback: make writeback_control track the inode being written back writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb() mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback support is in use writeback: implement memcg writeback domain based throttling writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changes writeback: implement memcg wb_domain writeback: update wb_over_bg_thresh() to use wb_domain aware operations ...
| * | | | | bdi: fix wrong error return value in cgwb_create()Tejun Heo2015-06-041-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On wb_congested_get_create() failure, cgwb_create() forgot to set @ret to -ENOMEM ending up returning 0. Fix it so that it returns -ENOMEM. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement unlocked_inode_to_wb transaction and use it for stat ↵Tejun Heo2015-06-022-7/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | updates The mechanism for detecting whether an inode should switch its wb (bdi_writeback) association is now in place. This patch build the framework for the actual switching. This patch adds a new inode flag I_WB_SWITCHING, which has two functions. First, the easy one, it ensures that there's only one switching in progress for a give inode. Second, it's used as a mechanism to synchronize wb stat updates. The two stats, WB_RECLAIMABLE and WB_WRITEBACK, aren't event counters but track the current number of dirty pages and pages under writeback respectively. As such, when an inode is moved from one wb to another, the inode's portion of those stats have to be transferred together; unfortunately, this is a bit tricky as those stat updates are percpu operations which are performed without holding any lock in some places. This patch solves the problem in a similar way as memcg. Each such lockless stat updates are wrapped in transaction surrounded by unlocked_inode_to_wb_begin/end(). During normal operation, they map to rcu_read_lock/unlock(); however, if I_WB_SWITCHING is asserted, mapping->tree_lock is grabbed across the transaction. In turn, the switching path sets I_WB_SWITCHING and waits for a RCU grace period to pass before actually starting to switch, which guarantees that all stat update paths are synchronizing against mapping->tree_lock. This patch still doesn't implement the actual switching. v3: Updated on top of the recent cancel_dirty_page() updates. unlocked_inode_to_wb_begin() now nests inside mem_cgroup_begin_page_stat() to match the locking order. v2: The i_wb access transaction will be used for !stat accesses too. Function names and comments updated accordingly. s/inode_wb_stat_unlocked_{begin|end}/unlocked_inode_to_wb_{begin|end}/ s/switch_wb/switch_wbs/ Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make writeback_control track the inode being written backTejun Heo2015-06-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, for cgroup writeback, the IO submission paths directly associate the bio's with the blkcg from inode_to_wb_blkcg_css(); however, it'd be necessary to keep more writeback context to implement foreign inode writeback detection. wbc (writeback_control) is the natural fit for the extra context - it persists throughout the writeback of each inode and is passed all the way down to IO submission paths. This patch adds wbc_attach_and_unlock_inode(), wbc_detach_inode(), and wbc_attach_fdatawrite_inode() which are used to associate wbc with the inode being written back. IO submission paths now use wbc_init_bio() instead of directly associating bio's with blkcg themselves. This leaves inode_to_wb_blkcg_css() w/o any user. The function is removed. wbc currently only tracks the associated wb (bdi_writeback). Future patches will add more for foreign inode detection. The association is established under i_lock which will be depended upon when migrating foreign inodes to other wb's. As currently, once established, inode to wb association never changes, going through wbc when initializing bio's doesn't cause any behavior changes. v2: submit_blk_blkcg() now checks whether the wbc is associated with a wb before dereferencing it. This can happen when pageout() is writing pages directly without going through the usual writeback path. As pageout() path is single-threaded, we don't want it to be blocked behind a slow cgroup and ultimately want it to delegate actual writing to the usual writeback path. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: relocate wb[_try]_get(), wb_put(), inode_{attach|detach}_wb()Tejun Heo2015-06-021-30/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, majority of cgroup writeback support including all the above functions are implemented in include/linux/backing-dev.h and mm/backing-dev.c; however, the portion closely related to writeback logic implemented in include/linux/writeback.h and mm/page-writeback.c will expand to support foreign writeback detection and correction. This patch moves wb[_try]_get() and wb_put() to include/linux/backing-dev-defs.h so that they can be used from writeback.h and inode_{attach|detach}_wb() to writeback.h and page-writeback.c. This is pure reorganization and doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | mm: vmscan: disable memcg direct reclaim stalling if cgroup writeback ↵Tejun Heo2015-06-021-10/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | support is in use Because writeback wasn't cgroup aware before, the usual dirty throttling mechanism in balance_dirty_pages() didn't work for processes under memcg limit. The writeback path didn't know how much memory is available or how fast the dirty pages are being written out for a given memcg and balance_dirty_pages() didn't have any measure of IO back pressure for the memcg. To work around the issue, memcg implemented an ad-hoc dirty throttling mechanism in the direct reclaim path by stalling on pages under writeback which are encountered during direct reclaim scan. This is rather ugly and crude - none of the configurability, fairness, or bandwidth-proportional distribution of the normal path. The previous patches implemented proper memcg aware dirty throttling when cgroup writeback is in use making the ad-hoc mechanism unnecessary. This patch disables direct reclaim stalling for such case. Note: I disabled the parts which seemed obvious and it behaves fine while testing but my understanding of this code path is rudimentary and it's quite possible that I got something wrong. Please let me know if I got some wrong or more global_reclaim() sites should be updated. v2: The original patch removed the direct stalling mechanism which breaks legacy hierarchies. Conditionalize instead of removing. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement memcg writeback domain based throttlingTejun Heo2015-06-022-22/+179
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While cgroup writeback support now connects memcg and blkcg so that writeback IOs are properly attributed and controlled, the IO back pressure propagation mechanism implemented in balance_dirty_pages() and its subroutines wasn't aware of cgroup writeback. Processes belonging to a memcg may have access to only subset of total memory available in the system and not factoring this into dirty throttling rendered it completely ineffective for processes under memcg limits and memcg ended up building a separate ad-hoc degenerate mechanism directly into vmscan code to limit page dirtying. The previous patches updated balance_dirty_pages() and its subroutines so that they can deal with multiple wb_domain's (writeback domains) and defined per-memcg wb_domain. Processes belonging to a non-root memcg are bound to two wb_domains, global wb_domain and memcg wb_domain, and should be throttled according to IO pressures from both domains. This patch updates dirty throttling code so that it repeats similar calculations for the two domains - the differences between the two are few and minor - and applies the lower of the two sets of resulting constraints. wb_over_bg_thresh(), which controls when background writeback terminates, is also updated to consider both global and memcg wb_domains. It returns true if dirty is over bg_thresh for either domain. This makes the dirty throttling mechanism operational for memcg domains including writeback-bandwidth-proportional dirty page distribution inside them but the ad-hoc memcg throttling mechanism in vmscan is still in place. The next patch will rip it out. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: reset wb_domain->dirty_limit[_tstmp] when memcg domain size changesTejun Heo2015-06-021-0/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The amount of available memory to a memcg wb_domain can change as memcg configuration changes. A domain's ->dirty_limit exists to smooth out sudden drops in dirty threshold; however, when a domain's size actually drops significantly, it hinders the dirty throttling from adjusting to the new configuration leading to unexpected behaviors including unnecessary OOM kills. This patch resolves the issue by adding wb_domain_size_changed() which resets ->dirty_limit[_tstmp] and making memcg call it on configuration changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: implement memcg wb_domainTejun Heo2015-06-023-1/+72
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dirtyable memory is distributed to a wb (bdi_writeback) according to the relative bandwidth the wb is writing out in the whole system. This distribution is global - each wb is measured against all other wb's and gets the proportinately sized portion of the memory in the whole system. For cgroup writeback, the amount of dirtyable memory is scoped by memcg and thus each wb would need to be measured and controlled in its memcg. IOW, a wb will belong to two writeback domains - the global and memcg domains. The previous patches laid the groundwork to support the two wb_domains and this patch implements memcg wb_domain. memcg->cgwb_domain is initialized on css online and destroyed on css release, wb->memcg_completions is added, and __wb_writeout_inc() is updated to increment completions against both global and memcg wb_domains. The following patches will update balance_dirty_pages() and its subroutines to actually consider memcg wb_domain for throttling. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: update wb_over_bg_thresh() to use wb_domain aware operationsTejun Heo2015-06-021-5/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | wb_over_bg_thresh() currently uses global_dirty_limits() and wb_dirty_limit() both of which are wrappers around operations which take dirty_throttle_control. For cgroup writeback support, the function will be updated to also consider memcg wb_domains which requires the context information carried in dirty_throttle_control. This patch updates wb_over_bg_thresh() so that it uses the underlying wb_domain aware operations directly and builds the global dirty_throttle_control in the process. This patch doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: move over_bground_thresh() to mm/page-writeback.cTejun Heo2015-06-021-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | and rename it to wb_over_bg_thresh(). The function is closely tied to the dirty throttling mechanism implemented in page-writeback.c. This relocation will allow future updates necessary for cgroup writeback support. While at it, add function comment. This is pure reorganization and doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: separate out domain_dirty_limits()Tejun Heo2015-06-021-25/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | global_dirty_limits() calculates thresh and bg_thresh (confusingly called *pdirty and *pbackground in the function) assuming global_wb_domain; however, cgroup writeback support requires considering per-memcg wb_domain too. This patch separates out domain_dirty_limits() which takes dirty_throttle_control out of global_dirty_limits(). As thresh and bg_thresh calculation needs the amount of dirtyable memory in the domain, dirty_throttle_control->avail is added. The new function calculates the two thresholds and store them directly in the dirty_throttle_control. Also, as memcg domains can't follow vm_dirty_bytes and dirty_background_bytes settings directly. If those are set and domain_dirty_limits() is invoked for a !global domain, the settings are translated to ratios by scaling them against globally available memory. dirty_throttle_control->gdtc is added to enable this when CONFIG_CGROUP_WRITEBACK. global_dirty_limits() is now a thin wrapper around domain_dirty_limits() and balance_dirty_pages() is updated to use the new function too. This patch doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: make __wb_writeout_inc() and hard_dirty_limit() take wb_domaas a ↵Tejun Heo2015-06-021-16/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | parameter Currently __wb_writeout_inc() and hard_dirty_limit() assume global_wb_domain; however, cgroup writeback support requires considering per-memcg wb_domain too. This patch separates out domain-specific part of __wb_writeout_inc() into wb_domain_writeout_inc() which takes wb_domain as a parameter and adds the parameter to hard_dirty_limit(). This will allow these two functions to handle per-memcg wb_domains. This patch doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
| * | | | | writeback: add dirty_throttle_control->domTejun Heo2015-06-021-6/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently all dirty throttle operations use global_wb_domain; however, cgroup writeback support requires considering per-memcg wb_domain too. This patch adds dirty_throttle_control->dom and updates functions which are directly using globabl_wb_domain to use it instead. As this makes global_update_bandwidth() a misnomer, the function is renamed to domain_update_bandwidth(). This patch doesn't introduce any behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>