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2017-09-13mm: treewide: remove GFP_TEMPORARY allocation flagMichal Hocko
GFP_TEMPORARY was introduced by commit e12ba74d8ff3 ("Group short-lived and reclaimable kernel allocations") along with __GFP_RECLAIMABLE. It's primary motivation was to allow users to tell that an allocation is short lived and so the allocator can try to place such allocations close together and prevent long term fragmentation. As much as this sounds like a reasonable semantic it becomes much less clear when to use the highlevel GFP_TEMPORARY allocation flag. How long is temporary? Can the context holding that memory sleep? Can it take locks? It seems there is no good answer for those questions. The current implementation of GFP_TEMPORARY is basically GFP_KERNEL | __GFP_RECLAIMABLE which in itself is tricky because basically none of the existing caller provide a way to reclaim the allocated memory. So this is rather misleading and hard to evaluate for any benefits. I have checked some random users and none of them has added the flag with a specific justification. I suspect most of them just copied from other existing users and others just thought it might be a good idea to use without any measuring. This suggests that GFP_TEMPORARY just motivates for cargo cult usage without any reasoning. I believe that our gfp flags are quite complex already and especially those with highlevel semantic should be clearly defined to prevent from confusion and abuse. Therefore I propose dropping GFP_TEMPORARY and replace all existing users to simply use GFP_KERNEL. Please note that SLAB users with shrinkers will still get __GFP_RECLAIMABLE heuristic and so they will be placed properly for memory fragmentation prevention. I can see reasons we might want some gfp flag to reflect shorterm allocations but I propose starting from a clear semantic definition and only then add users with proper justification. This was been brought up before LSF this year by Matthew [1] and it turned out that GFP_TEMPORARY really doesn't have a clear semantic. It seems to be a heuristic without any measured advantage for most (if not all) its current users. The follow up discussion has revealed that opinions on what might be temporary allocation differ a lot between developers. So rather than trying to tweak existing users into a semantic which they haven't expected I propose to simply remove the flag and start from scratch if we really need a semantic for short term allocations. [1] http://lkml.kernel.org/r/20170118054945.GD18349@bombadil.infradead.org [akpm@linux-foundation.org: fix typo] [akpm@linux-foundation.org: coding-style fixes] [sfr@canb.auug.org.au: drm/i915: fix up] Link: http://lkml.kernel.org/r/20170816144703.378d4f4d@canb.auug.org.au Link: http://lkml.kernel.org/r/20170728091904.14627-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Matthew Wilcox <willy@infradead.org> Cc: Neil Brown <neilb@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-08xen: set error code on failuresPan Bian
Variable rc is reset in the loop, and its value will be non-negative during the second and after repeat of the loop. If it fails to allocate memory then, it may return a non-negative integer, which indicates no error. This patch fixes the bug, assigning "-ENOMEM" to rc when kzalloc() or alloc_page() returns NULL, and removing the initialization of rc outside of the loop. Signed-off-by: Pan Bian <bianpan2016@163.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2016-07-06xen: use vma_pages().Muhammad Falak R Wani
Replace explicit computation of vma page count by a call to vma_pages(). Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-09-10Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge third patch-bomb from Andrew Morton: - even more of the rest of MM - lib/ updates - checkpatch updates - small changes to a few scruffy filesystems - kmod fixes/cleanups - kexec updates - a dma-mapping cleanup series from hch * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (81 commits) dma-mapping: consolidate dma_set_mask dma-mapping: consolidate dma_supported dma-mapping: cosolidate dma_mapping_error dma-mapping: consolidate dma_{alloc,free}_noncoherent dma-mapping: consolidate dma_{alloc,free}_{attrs,coherent} mm: use vma_is_anonymous() in create_huge_pmd() and wp_huge_pmd() mm: make sure all file VMAs have ->vm_ops set mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff() mm: mark most vm_operations_struct const namei: fix warning while make xmldocs caused by namei.c ipc: convert invalid scenarios to use WARN_ON zlib_deflate/deftree: remove bi_reverse() lib/decompress_unlzma: Do a NULL check for pointer lib/decompressors: use real out buf size for gunzip with kernel fs/affs: make root lookup from blkdev logical size sysctl: fix int -> unsigned long assignments in INT_MIN case kexec: export KERNEL_IMAGE_SIZE to vmcoreinfo kexec: align crash_notes allocation to make it be inside one physical page kexec: remove unnecessary test in kimage_alloc_crash_control_pages() kexec: split kexec_load syscall from kexec core code ...
2015-09-10mm: mark most vm_operations_struct constKirill A. Shutemov
With two exceptions (drm/qxl and drm/radeon) all vm_operations_struct structs should be constant. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Minchan Kim <minchan@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08xen: Use correctly the Xen memory terminologiesJulien Grall
Based on include/xen/mm.h [1], Linux is mistakenly using MFN when GFN is meant, I suspect this is because the first support for Xen was for PV. This resulted in some misimplementation of helpers on ARM and confused developers about the expected behavior. For instance, with pfn_to_mfn, we expect to get an MFN based on the name. Although, if we look at the implementation on x86, it's returning a GFN. For clarity and avoid new confusion, replace any reference to mfn with gfn in any helpers used by PV drivers. The x86 code will still keep some reference of pfn_to_mfn which may be used by all kind of guests No changes as been made in the hypercall field, even though they may be invalid, in order to keep the same as the defintion in xen repo. Note that page_to_mfn has been renamed to xen_page_to_gfn to avoid a name to close to the KVM function gfn_to_page. Take also the opportunity to simplify simple construction such as pfn_to_mfn(page_to_pfn(page)) into xen_page_to_gfn. More complex clean up will come in follow-up patches. [1] http://xenbits.xen.org/gitweb/?p=xen.git;a=commitdiff;h=e758ed14f390342513405dd766e874934573e6cb Signed-off-by: Julien Grall <julien.grall@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Acked-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-09-04xen/gntalloc: safely delete grefs in add_grefs() undo pathDavid Vrabel
If a gref could not be added (perhaps because the limit has been reached or there are no more grant references available), the undo path may crash because __del_gref() frees the gref while it is being used for a list iteration. A comment suggests that using list_for_each_entry() is safe since the gref isn't removed from the list being iterated over, but it is freed and thus list_for_each_entry_safe() must be used. Also, explicitly delete the gref from the local per-file list, even though this is not strictly necessary. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2014-09-04xen/gntalloc: fix oops after runnning out of grant refsDavid Vrabel
Only set gref->gref_id if foreign access was successfully granted and the grant ref is valid. If gref->gref_id == -ENOSPC the test in __del_gref() would incorrectly attempt to end foreign access (because grant_ref_t is unsigned). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reported-by: Dave Scott <dave.scott@citrix.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2013-06-28xen: Convert printks to pr_<level>Joe Perches
Convert printks to pr_<level> (excludes printk(KERN_DEBUG...) to be more consistent throughout the xen subsystem. Add pr_fmt with KBUILD_MODNAME or "xen:" KBUILD_MODNAME Coalesce formats and add missing word spaces Add missing newlines Align arguments and reflow to 80 columns Remove DRV_NAME from formats as pr_fmt adds the same content This does change some of the prefixes of these messages but it also does make them more consistent. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2012-10-09mm: kill vma flag VM_RESERVED and mm->reserved_vm counterKonstantin Khlebnikov
A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA, currently it lost original meaning but still has some effects: | effect | alternative flags -+------------------------+--------------------------------------------- 1| account as reserved_vm | VM_IO 2| skip in core dump | VM_IO, VM_DONTDUMP 3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP 4| do not mlock | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP This patch removes reserved_vm counter from mm_struct. Seems like nobody cares about it, it does not exported into userspace directly, it only reduces total_vm showed in proc. Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP. remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP. remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP. [akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Carsten Otte <cotte@de.ibm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Eric Paris <eparis@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morris <james.l.morris@oracle.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Kentaro Takeda <takedakn@nttdata.co.jp> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Venkatesh Pallipadi <venki@google.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-03xen-gntalloc: introduce missing kfreeJulia Lawall
Error handling code following a kmalloc should free the allocated data. Out_unlock is used on both success and failure, so free vm_priv before jumping to that label. A simplified version of the semantic match that finds the problem is as follows: (http://coccinelle.lip6.fr) // <smpl> @r exists@ local idexpression x; statement S; identifier f1; position p1,p2; expression *ptr != NULL; @@ x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...); ... if (x == NULL) S <... when != x when != if (...) { <+...x...+> } x->f1 ...> ( return \(0\|<+...x...+>\|ptr\); | return@p2 ...; ) @script:python@ p1 << r.p1; p2 << r.p2; @@ print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line) // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> [v1: Altered the description a bit] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-12-20Merge commit 'v3.2-rc3' into stable/for-linus-3.3Konrad Rzeszutek Wilk
* commit 'v3.2-rc3': (412 commits) Linux 3.2-rc3 virtio-pci: make reset operation safer virtio-mmio: Correct the name of the guest features selector virtio: add HAS_IOMEM dependency to MMIO platform bus driver eCryptfs: Extend array bounds for all filename chars eCryptfs: Flush file in vma close eCryptfs: Prevent file create race condition regulator: TPS65910: Fix VDD1/2 voltage selector count i2c: Make i2cdev_notifier_call static i2c: Delete ANY_I2C_BUS i2c: Fix device name for 10-bit slave address i2c-algo-bit: Generate correct i2c address sequence for 10-bit target drm: integer overflow in drm_mode_dirtyfb_ioctl() Revert "of/irq: of_irq_find_parent: check for parent equal to child" drivers/gpu/vga/vgaarb.c: add missing kfree drm/radeon/kms/atom: unify i2c gpio table handling drm/radeon/kms: fix up gpio i2c mask bits for r4xx for real ttm: Don't return the bo reserved on error path mount_subtree() pointless use-after-free iio: fix a leak due to improper use of anon_inode_getfd() ...
2011-12-16xen/gntalloc: fix reference counts on multi-page mappingsDaniel De Graaf
When a multi-page mapping of gntalloc is created, the reference counts of all pages in the vma are incremented. However, the vma open/close operations only adjusted the reference count of the first page in the mapping, leaking the other pages. Store a struct in the vm_private_data to track the original page count to properly free the pages when the last reference to the vma is closed. Reported-by: Anil Madhavapeddy <anil@recoil.org> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-12-16xen/gntalloc: release grant references on page freeDaniel De Graaf
gnttab_end_foreign_access_ref does not return the grant reference it is passed to the free list; gnttab_free_grant_reference needs to be explicitly called. While gnttab_end_foreign_access provides a wrapper for this, it is unsuitable because it does not return errors. Reported-by: Anil Madhavapeddy <anil@recoil.org> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-11-21xen/gnt{dev,alloc}: reserve event channels for notifyDaniel De Graaf
When using the unmap notify ioctl, the event channel used for notification needs to be reserved to avoid it being deallocated prior to sending the notification. Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-11-21xen/gntalloc: Change gref_lock to a mutexDaniel De Graaf
The event channel release function cannot be called under a spinlock because it can attempt to acquire a mutex due to the event channel reference acquired when setting up unmap notifications. Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-11-16xen-gntalloc: signedness bug in add_grefs()Dan Carpenter
gref->gref_id is unsigned so the error handling didn't work. gnttab_grant_foreign_access() returns an int type, so we can add a cast here, and it doesn't cause any problems. gnttab_grant_foreign_access() can return a variety of errors including -ENOSPC, -ENOSYS and -ENOMEM. CC: stable@kernel.org Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-11-16xen-gntalloc: integer overflow in gntalloc_ioctl_alloc()Dan Carpenter
On 32 bit systems a high value of op.count could lead to an integer overflow in the kzalloc() and gref_ids would be smaller than expected. If the you triggered another integer overflow in "if (gref_size + op.count > limit)" then you'd probably get memory corruption inside add_grefs(). CC: stable@kernel.org Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-03-09xen/gntdev,gntalloc: Remove unneeded VM flagsDaniel De Graaf
The only time when granted pages need to be treated specially is when using Xen's PTE modification for grant mappings owned by another domain (that is, only gntdev on PV guests). Otherwise, the area does not require VM_DONTCOPY and VM_PFNMAP, since it can be accessed just like any other page of RAM. Since the vm_operations_struct close operations decrement reference counts, a corresponding open function that increments them is required now that it is possible to have multiple references to a single area. We are careful in the gntdev to check if we can remove those flags. The reason that we need to be careful in gntdev on PV guests is because we are not changing the PFN/MFN mapping on PV; instead, we change the application's page tables to point to the other domain's memory. This means that the vma cannot be copied without using another grant mapping hypercall; it also requires special handling on unmap, which is the reason for gntdev's dependency on the MMU notifier. For gntalloc, this is not a concern - the pages are owned by the domain using the gntalloc device, and can be mapped and unmapped in the same manner as any other page of memory. Acked-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v2: Added in git commit "We are.." from email correspondence]
2011-02-14xen/gntalloc,gntdev: Add unmap notify ioctlDaniel De Graaf
This ioctl allows the users of a shared page to be notified when the other end exits abnormally. [v2: updated description in structs] Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2011-02-14xen-gntalloc: Userspace grant allocation driverDaniel De Graaf
This allows a userspace application to allocate a shared page for implementing inter-domain communication or device drivers. These shared pages can be mapped using the gntdev device or by the kernel in another domain. Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>