![David Rientjes](/assets/img/avatar_default.png)
This is a full revert ofac5b2c1891
("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings") and a partial revert of89c83fb539
("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask"). By not setting __GFP_THISNODE, applications can allocate remote hugepages when the local node is fragmented or low on memory when either the thp defrag setting is "always" or the vma has been madvised with MADV_HUGEPAGE. Remote access to hugepages often has much higher latency than local pages of the native page size. On Haswell,ac5b2c1891
was shown to have a 13.9% access regression after this commit for binaries that remap their text segment to be backed by transparent hugepages. The intent ofac5b2c1891
is to address an issue where a local node is low on memory or fragmented such that a hugepage cannot be allocated. In every scenario where this was described as a fix, there is abundant and unfragmented remote memory available to allocate from, even with a greater access latency. If remote memory is also low or fragmented, not setting __GFP_THISNODE was also measured on Haswell to have a 40% regression in allocation latency. Restore __GFP_THISNODE for thp allocations. Fixes:ac5b2c1891
("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings") Fixes:89c83fb539
("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask") Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
313 lines
7.4 KiB
C
313 lines
7.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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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 _LINUX_MEMPOLICY_H
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#define _LINUX_MEMPOLICY_H 1
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#include <linux/mmzone.h>
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#include <linux/dax.h>
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#include <linux/slab.h>
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#include <linux/rbtree.h>
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#include <linux/spinlock.h>
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#include <linux/nodemask.h>
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#include <linux/pagemap.h>
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#include <uapi/linux/mempolicy.h>
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struct mm_struct;
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#ifdef CONFIG_NUMA
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/*
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* Describe a memory policy.
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*
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* A mempolicy can be either associated with a process or with a VMA.
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* For VMA related allocations the VMA policy is preferred, otherwise
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* the process policy is used. Interrupts ignore the memory policy
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* of the current process.
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*
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* Locking policy for interlave:
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* In process context there is no locking because only the process accesses
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* its own state. All vma manipulation is somewhat protected by a down_read on
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* mmap_sem.
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*
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* Freeing policy:
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* Mempolicy objects are reference counted. A mempolicy will be freed when
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* mpol_put() decrements the reference count to zero.
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*
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* Duplicating policy objects:
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* mpol_dup() allocates a new mempolicy and copies the specified mempolicy
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* to the new storage. The reference count of the new object is initialized
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* to 1, representing the caller of mpol_dup().
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*/
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struct mempolicy {
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atomic_t refcnt;
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unsigned short mode; /* See MPOL_* above */
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unsigned short flags; /* See set_mempolicy() MPOL_F_* above */
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union {
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short preferred_node; /* preferred */
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nodemask_t nodes; /* interleave/bind */
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/* undefined for default */
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} v;
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union {
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nodemask_t cpuset_mems_allowed; /* relative to these nodes */
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nodemask_t user_nodemask; /* nodemask passed by user */
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} w;
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};
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/*
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* Support for managing mempolicy data objects (clone, copy, destroy)
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* The default fast path of a NULL MPOL_DEFAULT policy is always inlined.
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*/
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extern void __mpol_put(struct mempolicy *pol);
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static inline void mpol_put(struct mempolicy *pol)
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{
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if (pol)
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__mpol_put(pol);
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}
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/*
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* Does mempolicy pol need explicit unref after use?
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* Currently only needed for shared policies.
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*/
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static inline int mpol_needs_cond_ref(struct mempolicy *pol)
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{
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return (pol && (pol->flags & MPOL_F_SHARED));
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}
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static inline void mpol_cond_put(struct mempolicy *pol)
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{
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if (mpol_needs_cond_ref(pol))
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__mpol_put(pol);
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}
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extern struct mempolicy *__mpol_dup(struct mempolicy *pol);
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static inline struct mempolicy *mpol_dup(struct mempolicy *pol)
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{
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if (pol)
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pol = __mpol_dup(pol);
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return pol;
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}
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#define vma_policy(vma) ((vma)->vm_policy)
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static inline void mpol_get(struct mempolicy *pol)
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{
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if (pol)
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atomic_inc(&pol->refcnt);
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}
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extern bool __mpol_equal(struct mempolicy *a, struct mempolicy *b);
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static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b)
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{
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if (a == b)
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return true;
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return __mpol_equal(a, b);
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}
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/*
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* Tree of shared policies for a shared memory region.
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* Maintain the policies in a pseudo mm that contains vmas. The vmas
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* carry the policy. As a special twist the pseudo mm is indexed in pages, not
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* bytes, so that we can work with shared memory segments bigger than
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* unsigned long.
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*/
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struct sp_node {
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struct rb_node nd;
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unsigned long start, end;
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struct mempolicy *policy;
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};
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struct shared_policy {
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struct rb_root root;
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rwlock_t lock;
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};
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int vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst);
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void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol);
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int mpol_set_shared_policy(struct shared_policy *info,
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struct vm_area_struct *vma,
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struct mempolicy *new);
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void mpol_free_shared_policy(struct shared_policy *p);
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struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp,
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unsigned long idx);
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struct mempolicy *get_task_policy(struct task_struct *p);
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struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
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unsigned long addr);
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bool vma_policy_mof(struct vm_area_struct *vma);
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extern void numa_default_policy(void);
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extern void numa_policy_init(void);
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extern void mpol_rebind_task(struct task_struct *tsk, const nodemask_t *new);
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extern void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new);
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extern int huge_node(struct vm_area_struct *vma,
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unsigned long addr, gfp_t gfp_flags,
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struct mempolicy **mpol, nodemask_t **nodemask);
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extern bool init_nodemask_of_mempolicy(nodemask_t *mask);
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extern bool mempolicy_nodemask_intersects(struct task_struct *tsk,
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const nodemask_t *mask);
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extern unsigned int mempolicy_slab_node(void);
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extern enum zone_type policy_zone;
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static inline void check_highest_zone(enum zone_type k)
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{
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if (k > policy_zone && k != ZONE_MOVABLE)
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policy_zone = k;
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}
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int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
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const nodemask_t *to, int flags);
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#ifdef CONFIG_TMPFS
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extern int mpol_parse_str(char *str, struct mempolicy **mpol);
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#endif
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extern void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol);
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/* Check if a vma is migratable */
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static inline bool vma_migratable(struct vm_area_struct *vma)
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{
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if (vma->vm_flags & (VM_IO | VM_PFNMAP))
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return false;
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/*
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* DAX device mappings require predictable access latency, so avoid
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* incurring periodic faults.
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*/
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if (vma_is_dax(vma))
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return false;
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#ifndef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
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if (vma->vm_flags & VM_HUGETLB)
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return false;
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#endif
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/*
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* Migration allocates pages in the highest zone. If we cannot
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* do so then migration (at least from node to node) is not
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* possible.
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*/
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if (vma->vm_file &&
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gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
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< policy_zone)
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return false;
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return true;
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}
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extern int mpol_misplaced(struct page *, struct vm_area_struct *, unsigned long);
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extern void mpol_put_task_policy(struct task_struct *);
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#else
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struct mempolicy {};
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static inline bool mpol_equal(struct mempolicy *a, struct mempolicy *b)
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{
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return true;
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}
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static inline void mpol_put(struct mempolicy *p)
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{
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}
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static inline void mpol_cond_put(struct mempolicy *pol)
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{
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}
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static inline void mpol_get(struct mempolicy *pol)
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{
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}
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struct shared_policy {};
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static inline void mpol_shared_policy_init(struct shared_policy *sp,
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struct mempolicy *mpol)
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{
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}
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static inline void mpol_free_shared_policy(struct shared_policy *p)
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{
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}
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static inline struct mempolicy *
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mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx)
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{
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return NULL;
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}
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#define vma_policy(vma) NULL
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static inline int
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vma_dup_policy(struct vm_area_struct *src, struct vm_area_struct *dst)
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{
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return 0;
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}
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static inline void numa_policy_init(void)
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{
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}
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static inline void numa_default_policy(void)
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{
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}
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static inline void mpol_rebind_task(struct task_struct *tsk,
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const nodemask_t *new)
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{
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}
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static inline void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
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{
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}
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static inline int huge_node(struct vm_area_struct *vma,
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unsigned long addr, gfp_t gfp_flags,
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struct mempolicy **mpol, nodemask_t **nodemask)
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{
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*mpol = NULL;
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*nodemask = NULL;
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return 0;
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}
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static inline bool init_nodemask_of_mempolicy(nodemask_t *m)
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{
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return false;
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}
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static inline int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
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const nodemask_t *to, int flags)
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{
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return 0;
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}
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static inline void check_highest_zone(int k)
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{
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}
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#ifdef CONFIG_TMPFS
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static inline int mpol_parse_str(char *str, struct mempolicy **mpol)
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{
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return 1; /* error */
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}
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#endif
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static inline int mpol_misplaced(struct page *page, struct vm_area_struct *vma,
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unsigned long address)
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{
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return -1; /* no node preference */
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}
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static inline void mpol_put_task_policy(struct task_struct *task)
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{
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}
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#endif /* CONFIG_NUMA */
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#endif
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