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213980c0f2
Commitc0ff7453bb("cpuset,mm: fix no node to alloc memory when changing cpuset's mems") has introduced a two-step protocol when rebinding task's mempolicy due to cpuset update, in order to avoid a parallel allocation seeing an empty effective nodemask and failing. Later, commitcc9a6c8776("cpuset: mm: reduce large amounts of memory barrier related damage v3") introduced a seqlock protection and removed the synchronization point between the two update steps. At that point (or perhaps later), the two-step rebinding became unnecessary. Currently it only makes sure that the update first adds new nodes in step 1 and then removes nodes in step 2. Without memory barriers the effects are questionable, and even then this cannot prevent a parallel zonelist iteration checking the nodemask at each step to observe all nodes as unusable for allocation. We now fully rely on the seqlock to prevent premature OOMs and allocation failures. We can thus remove the two-step update parts and simplify the code. Link: http://lkml.kernel.org/r/20170517081140.30654-5-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dimitri Sivanich <sivanich@sgi.com> Cc: Hugh Dickins <hughd@google.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
66 lines
2.1 KiB
C
66 lines
2.1 KiB
C
/*
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* NUMA memory policies for Linux.
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* Copyright 2003,2004 Andi Kleen SuSE Labs
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*/
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#ifndef _UAPI_LINUX_MEMPOLICY_H
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#define _UAPI_LINUX_MEMPOLICY_H
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#include <linux/errno.h>
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/*
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* Both the MPOL_* mempolicy mode and the MPOL_F_* optional mode flags are
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* passed by the user to either set_mempolicy() or mbind() in an 'int' actual.
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* The MPOL_MODE_FLAGS macro determines the legal set of optional mode flags.
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*/
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/* Policies */
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enum {
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MPOL_DEFAULT,
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MPOL_PREFERRED,
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MPOL_BIND,
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MPOL_INTERLEAVE,
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MPOL_LOCAL,
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MPOL_MAX, /* always last member of enum */
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};
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/* Flags for set_mempolicy */
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#define MPOL_F_STATIC_NODES (1 << 15)
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#define MPOL_F_RELATIVE_NODES (1 << 14)
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/*
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* MPOL_MODE_FLAGS is the union of all possible optional mode flags passed to
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* either set_mempolicy() or mbind().
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*/
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#define MPOL_MODE_FLAGS (MPOL_F_STATIC_NODES | MPOL_F_RELATIVE_NODES)
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/* Flags for get_mempolicy */
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#define MPOL_F_NODE (1<<0) /* return next IL mode instead of node mask */
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#define MPOL_F_ADDR (1<<1) /* look up vma using address */
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#define MPOL_F_MEMS_ALLOWED (1<<2) /* return allowed memories */
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/* Flags for mbind */
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#define MPOL_MF_STRICT (1<<0) /* Verify existing pages in the mapping */
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#define MPOL_MF_MOVE (1<<1) /* Move pages owned by this process to conform
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to policy */
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#define MPOL_MF_MOVE_ALL (1<<2) /* Move every page to conform to policy */
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#define MPOL_MF_LAZY (1<<3) /* Modifies '_MOVE: lazy migrate on fault */
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#define MPOL_MF_INTERNAL (1<<4) /* Internal flags start here */
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#define MPOL_MF_VALID (MPOL_MF_STRICT | \
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MPOL_MF_MOVE | \
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MPOL_MF_MOVE_ALL)
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/*
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* Internal flags that share the struct mempolicy flags word with
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* "mode flags". These flags are allocated from bit 0 up, as they
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* are never OR'ed into the mode in mempolicy API arguments.
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*/
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#define MPOL_F_SHARED (1 << 0) /* identify shared policies */
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#define MPOL_F_LOCAL (1 << 1) /* preferred local allocation */
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#define MPOL_F_MOF (1 << 3) /* this policy wants migrate on fault */
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#define MPOL_F_MORON (1 << 4) /* Migrate On protnone Reference On Node */
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#endif /* _UAPI_LINUX_MEMPOLICY_H */
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