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David Rientjes def5efe037 mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count
If madvise(2) advice will result in the underlying vma being split and
the number of areas mapped by the process will exceed
/proc/sys/vm/max_map_count as a result, return ENOMEM instead of EAGAIN.

EAGAIN is returned by madvise(2) when a kernel resource, such as slab,
is temporarily unavailable.  It indicates that userspace should retry
the advice in the near future.  This is important for advice such as
MADV_DONTNEED which is often used by malloc implementations to free
memory back to the system: we really do want to free memory back when
madvise(2) returns EAGAIN because slab allocations (for vmas, anon_vmas,
or mempolicies) cannot be allocated.

Encountering /proc/sys/vm/max_map_count is not a temporary failure,
however, so return ENOMEM to indicate this is a more serious issue.  A
followup patch to the man page will specify this behavior.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1701241431120.42507@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michael Kerrisk <mtk.manpages@googlemail.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:55 -08:00
arch mm: wire up GFP flag passing in dma_alloc_from_contiguous 2017-02-24 17:46:55 -08:00
block
certs
crypto
Documentation mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count 2017-02-24 17:46:55 -08:00
drivers mm: wire up GFP flag passing in dma_alloc_from_contiguous 2017-02-24 17:46:55 -08:00
firmware
fs userfaultfd_copy: return -ENOSPC in case mm has gone 2017-02-24 17:46:55 -08:00
include mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count 2017-02-24 17:46:55 -08:00
init
ipc userfaultfd: non-cooperative: add event for memory unmaps 2017-02-24 17:46:55 -08:00
kernel userfaultfd: non-cooperative: add event for exit() notification 2017-02-24 17:46:55 -08:00
lib Less anger inducing pull request for 4.11 2017-02-23 18:58:18 -08:00
mm mm, madvise: fail with ENOMEM when splitting vma will hit max_map_count 2017-02-24 17:46:55 -08:00
net
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security mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf 2017-02-24 17:46:54 -08:00
sound mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf 2017-02-24 17:46:54 -08:00
tools userfaultfd: non-cooperative: selftest: enable REMOVE event test for shmem 2017-02-24 17:46:54 -08:00
usr
virt mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf 2017-02-24 17:46:54 -08:00
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MAINTAINERS Less anger inducing pull request for 4.11 2017-02-23 18:58:18 -08:00
Makefile
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.