linux-stable.git/mm/vmalloc.c, branch v5.9.8

mm/vunmap: add cond_resched() in vunmap_pmd_range

2020-08-21T16:52:53+00:00

Like zap_pte_range add cond_resched so that we can avoid softlockups as
reported below.  On non-preemptible kernel with large I/O map region (like
the one we get when using persistent memory with sector mode), an unmap of
the namespace can report below softlockups.

22724.027334] watchdog: BUG: soft lockup - CPU#49 stuck for 23s! [ndctl:50777]
 NIP [c0000000000dc224] plpar_hcall+0x38/0x58
 LR [c0000000000d8898] pSeries_lpar_hpte_invalidate+0x68/0xb0
 Call Trace:
    flush_hash_page+0x114/0x200
    hpte_need_flush+0x2dc/0x540
    vunmap_page_range+0x538/0x6f0
    free_unmap_vmap_area+0x30/0x70
    remove_vm_area+0xfc/0x140
    __vunmap+0x68/0x270
    __iounmap.part.0+0x34/0x60
    memunmap+0x54/0x70
    release_nodes+0x28c/0x300
    device_release_driver_internal+0x16c/0x280
    unbind_store+0x124/0x170
    drv_attr_store+0x44/0x60
    sysfs_kf_write+0x64/0x90
    kernfs_fop_write+0x1b0/0x290
    __vfs_write+0x3c/0x70
    vfs_write+0xd8/0x260
    ksys_write+0xdc/0x130
    system_call+0x5c/0x70

Reported-by: Harish Sriram 
Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrew Morton 
Cc: 
Link: http://lkml.kernel.org/r/20200807075933.310240-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Linus Torvalds

mm/vmalloc.c: remove BUG() from the find_va_links()

2020-08-07T18:33:28+00:00

Get rid of BUG() macro, that should be used only when a critical situation
happens and a system is not able to function anymore.

Replace it with WARN() macro instead, dump some extra information about
start/end addresses of both VAs which overlap.  Such overlap data can help
to figure out what happened making further analysis easier.  For example
if both areas are identical it could mean a double free.

A recovery process consists of declining all further steps regarding
inserting of conflicting overlap range.  In that sense find_va_links() now
can return NULL, so its return value has to be checked by callers.

Side effect of such process is it can leak memory, but it is better than
just killing a machine for no good reason.  Apart of that a debugging
process can be done on alive system.

Signed-off-by: Uladzislau Rezki (Sony) 
Signed-off-by: Andrew Morton 
Cc: Hillf Danton 
Cc: Michal Hocko 
Cc: Matthew Wilcox 
Cc: Oleksiy Avramchenko 
Cc: Steven Rostedt 
Link: http://lkml.kernel.org/r/20200711104531.12242-1-urezki@gmail.com
Signed-off-by: Linus Torvalds

mm: vmalloc: remove redundant assignment in unmap_kernel_range_noflush()

2020-08-07T18:33:27+00:00

'addr' is set to 'start' and then a few lines afterwards 'start' is set to
'addr'.  Remove the second asignment.

Fixes: 2ba3e6947aed ("mm/vmalloc: track which page-table levels were modified")
Signed-off-by: Mike Rapoport 
Signed-off-by: Andrew Morton 
Reviewed-by: David Hildenbrand 
Cc: Joerg Roedel 
Link: http://lkml.kernel.org/r/20200707163226.374685-1-rppt@kernel.org
Signed-off-by: Linus Torvalds

mm/vmalloc: update the header about KVA rework

2020-08-07T18:33:27+00:00

Reflect information about the author, date and year when the KVA rework
was done.

Signed-off-by: Uladzislau Rezki (Sony) 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200622195821.4796-1-urezki@gmail.com
Signed-off-by: Linus Torvalds

mm/vmalloc: switch to "propagate()" callback

2020-08-07T18:33:27+00:00

An augment_tree_propagate_from() function uses its own implementation that
populates a tree from the specified node toward a root node.

On the other hand the RB_DECLARE_CALLBACKS_MAX macro provides the
"propagate()" callback that does exactly the same.  Having two similar
functions does not make sense and is redundant.

Reuse "built in" functionality to the macros.  So the code size gets
reduced.

Signed-off-by: Uladzislau Rezki (Sony) 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200527205054.1696-3-urezki@gmail.com
Signed-off-by: Linus Torvalds

mm/vmalloc: simplify augment_tree_propagate_check()

2020-08-07T18:33:27+00:00

This function is for debug purpose only.  Currently it uses recursion for
tree traversal, checking an augmented value of each node to find out if it
is valid or not.

The recursion can corrupt the stack because the tree can be huge if
synthetic tests are applied.  To prevent it, navigate the tree from bottom
to upper levels using a regular list instead, because nodes are linked
among each other also.  It is faster and without recursion.

Signed-off-by: Uladzislau Rezki (Sony) 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200527205054.1696-2-urezki@gmail.com
Signed-off-by: Linus Torvalds

mm/vmalloc: simplify merge_or_add_vmap_area()

2020-08-07T18:33:27+00:00

Currently when a VA is deallocated and is about to be placed back to the
tree, it can be either: merged with next/prev neighbors or inserted if not
coalesced.

On those steps the tree can be populated several times.  For example when
both neighbors are merged.  It can be avoided and simplified in fact.

Therefore do it only once when VA points to final merged area, after all
manipulations: merging/removing/inserting.

Signed-off-by: Uladzislau Rezki (Sony) 
Signed-off-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200527205054.1696-1-urezki@gmail.com
Signed-off-by: Linus Torvalds

vmalloc: convert to XArray

2020-08-07T18:33:27+00:00

The radix tree of vmap blocks is simpler to express as an XArray.  Reduces
both the text and data sizes of the object file and eliminates a user of
the radix tree preload API.

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Reviewed-by: William Kucharski 
Link: http://lkml.kernel.org/r/20200603171448.5894-1-willy@infradead.org
Signed-off-by: Linus Torvalds

mm: move p?d_alloc_track to separate header file

2020-08-07T18:33:26+00:00

The functions are only used in two source files, so there is no need for
them to be in the global  header.  Move them to the new
 header and include it only where needed.

Signed-off-by: Joerg Roedel 
Signed-off-by: Andrew Morton 
Reviewed-by: Pekka Enberg 
Cc: Peter Zijlstra (Intel) 
Cc: Andy Lutomirski 
Cc: Abdul Haleem 
Cc: Satheesh Rajendran 
Cc: Stephen Rothwell 
Cc: Steven Rostedt (VMware) 
Cc: Mike Rapoport 
Cc: Christophe Leroy 
Cc: Arnd Bergmann 
Cc: Max Filippov 
Cc: Stafford Horne 
Cc: Geert Uytterhoeven 
Cc: Matthew Wilcox 
Link: http://lkml.kernel.org/r/20200609120533.25867-1-joro@8bytes.org
Signed-off-by: Linus Torvalds

mm: remove vmalloc_exec

2020-06-26T07:27:38+00:00

Merge vmalloc_exec into its only caller.  Note that for !CONFIG_MMU
__vmalloc_node_range maps to __vmalloc, which directly clears the
__GFP_HIGHMEM added by the vmalloc_exec stub anyway.

Link: http://lkml.kernel.org/r/20200618064307.32739-4-hch@lst.de
Signed-off-by: Christoph Hellwig 
Reviewed-by: David Hildenbrand 
Acked-by: Peter Zijlstra (Intel) 
Cc: Catalin Marinas 
Cc: Dexuan Cui 
Cc: Jessica Yu 
Cc: Vitaly Kuznetsov 
Cc: Wei Liu 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds