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authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-16 14:33:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-16 15:18:08 -0800
commit3d59eebc5e137bd89c6351e4c70e90ba1d0dc234 (patch)
treeb4ddfd0b057454a7437a3b4e3074a3b8b4b03817 /mm/memory.c
parent11520e5e7c1855fc3bf202bb3be35a39d9efa034 (diff)
parent4fc3f1d66b1ef0d7b8dc11f4ff1cc510f78b37d6 (diff)
downloadlinux-3d59eebc5e137bd89c6351e4c70e90ba1d0dc234.tar.gz
Merge tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma
Pull Automatic NUMA Balancing bare-bones from Mel Gorman: "There are three implementations for NUMA balancing, this tree (balancenuma), numacore which has been developed in tip/master and autonuma which is in aa.git. In almost all respects balancenuma is the dumbest of the three because its main impact is on the VM side with no attempt to be smart about scheduling. In the interest of getting the ball rolling, it would be desirable to see this much merged for 3.8 with the view to building scheduler smarts on top and adapting the VM where required for 3.9. The most recent set of comparisons available from different people are mel: https://lkml.org/lkml/2012/12/9/108 mingo: https://lkml.org/lkml/2012/12/7/331 tglx: https://lkml.org/lkml/2012/12/10/437 srikar: https://lkml.org/lkml/2012/12/10/397 The results are a mixed bag. In my own tests, balancenuma does reasonably well. It's dumb as rocks and does not regress against mainline. On the other hand, Ingo's tests shows that balancenuma is incapable of converging for this workloads driven by perf which is bad but is potentially explained by the lack of scheduler smarts. Thomas' results show balancenuma improves on mainline but falls far short of numacore or autonuma. Srikar's results indicate we all suffer on a large machine with imbalanced node sizes. My own testing showed that recent numacore results have improved dramatically, particularly in the last week but not universally. We've butted heads heavily on system CPU usage and high levels of migration even when it shows that overall performance is better. There are also cases where it regresses. Of interest is that for specjbb in some configurations it will regress for lower numbers of warehouses and show gains for higher numbers which is not reported by the tool by default and sometimes missed in treports. Recently I reported for numacore that the JVM was crashing with NullPointerExceptions but currently it's unclear what the source of this problem is. Initially I thought it was in how numacore batch handles PTEs but I'm no longer think this is the case. It's possible numacore is just able to trigger it due to higher rates of migration. These reports were quite late in the cycle so I/we would like to start with this tree as it contains much of the code we can agree on and has not changed significantly over the last 2-3 weeks." * tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits) mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable mm/rmap: Convert the struct anon_vma::mutex to an rwsem mm: migrate: Account a transhuge page properly when rate limiting mm: numa: Account for failed allocations and isolations as migration failures mm: numa: Add THP migration for the NUMA working set scanning fault case build fix mm: numa: Add THP migration for the NUMA working set scanning fault case. mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG mm: sched: numa: Control enabling and disabling of NUMA balancing mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely task<->node relationships mm: numa: migrate: Set last_nid on newly allocated page mm: numa: split_huge_page: Transfer last_nid on tail page mm: numa: Introduce last_nid to the page frame sched: numa: Slowly increase the scanning period as NUMA faults are handled mm: numa: Rate limit setting of pte_numa if node is saturated mm: numa: Rate limit the amount of memory that is migrated between nodes mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting mm: numa: Migrate pages handled during a pmd_numa hinting fault mm: numa: Migrate on reference policy ...
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c198
1 files changed, 195 insertions, 3 deletions
diff --git a/mm/memory.c b/mm/memory.c
index db2e9e797a0..e6a3b933517 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -57,6 +57,7 @@
#include <linux/swapops.h>
#include <linux/elf.h>
#include <linux/gfp.h>
+#include <linux/migrate.h>
#include <asm/io.h>
#include <asm/pgalloc.h>
@@ -1503,6 +1504,8 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
goto out;
}
+ if ((flags & FOLL_NUMA) && pmd_numa(*pmd))
+ goto no_page_table;
if (pmd_trans_huge(*pmd)) {
if (flags & FOLL_SPLIT) {
split_huge_page_pmd(vma, address, pmd);
@@ -1532,6 +1535,8 @@ split_fallthrough:
pte = *ptep;
if (!pte_present(pte))
goto no_page;
+ if ((flags & FOLL_NUMA) && pte_numa(pte))
+ goto no_page;
if ((flags & FOLL_WRITE) && !pte_write(pte))
goto unlock;
@@ -1683,6 +1688,19 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
(VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
vm_flags &= (gup_flags & FOLL_FORCE) ?
(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+
+ /*
+ * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault
+ * would be called on PROT_NONE ranges. We must never invoke
+ * handle_mm_fault on PROT_NONE ranges or the NUMA hinting
+ * page faults would unprotect the PROT_NONE ranges if
+ * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd
+ * bitflag. So to avoid that, don't set FOLL_NUMA if
+ * FOLL_FORCE is set.
+ */
+ if (!(gup_flags & FOLL_FORCE))
+ gup_flags |= FOLL_NUMA;
+
i = 0;
do {
@@ -3412,6 +3430,169 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
}
+int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
+ unsigned long addr, int current_nid)
+{
+ get_page(page);
+
+ count_vm_numa_event(NUMA_HINT_FAULTS);
+ if (current_nid == numa_node_id())
+ count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
+
+ return mpol_misplaced(page, vma, addr);
+}
+
+int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
+{
+ struct page *page = NULL;
+ spinlock_t *ptl;
+ int current_nid = -1;
+ int target_nid;
+ bool migrated = false;
+
+ /*
+ * The "pte" at this point cannot be used safely without
+ * validation through pte_unmap_same(). It's of NUMA type but
+ * the pfn may be screwed if the read is non atomic.
+ *
+ * ptep_modify_prot_start is not called as this is clearing
+ * the _PAGE_NUMA bit and it is not really expected that there
+ * would be concurrent hardware modifications to the PTE.
+ */
+ ptl = pte_lockptr(mm, pmd);
+ spin_lock(ptl);
+ if (unlikely(!pte_same(*ptep, pte))) {
+ pte_unmap_unlock(ptep, ptl);
+ goto out;
+ }
+
+ pte = pte_mknonnuma(pte);
+ set_pte_at(mm, addr, ptep, pte);
+ update_mmu_cache(vma, addr, ptep);
+
+ page = vm_normal_page(vma, addr, pte);
+ if (!page) {
+ pte_unmap_unlock(ptep, ptl);
+ return 0;
+ }
+
+ current_nid = page_to_nid(page);
+ target_nid = numa_migrate_prep(page, vma, addr, current_nid);
+ pte_unmap_unlock(ptep, ptl);
+ if (target_nid == -1) {
+ /*
+ * Account for the fault against the current node if it not
+ * being replaced regardless of where the page is located.
+ */
+ current_nid = numa_node_id();
+ put_page(page);
+ goto out;
+ }
+
+ /* Migrate to the requested node */
+ migrated = migrate_misplaced_page(page, target_nid);
+ if (migrated)
+ current_nid = target_nid;
+
+out:
+ if (current_nid != -1)
+ task_numa_fault(current_nid, 1, migrated);
+ return 0;
+}
+
+/* NUMA hinting page fault entry point for regular pmds */
+#ifdef CONFIG_NUMA_BALANCING
+static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, pmd_t *pmdp)
+{
+ pmd_t pmd;
+ pte_t *pte, *orig_pte;
+ unsigned long _addr = addr & PMD_MASK;
+ unsigned long offset;
+ spinlock_t *ptl;
+ bool numa = false;
+ int local_nid = numa_node_id();
+
+ spin_lock(&mm->page_table_lock);
+ pmd = *pmdp;
+ if (pmd_numa(pmd)) {
+ set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd));
+ numa = true;
+ }
+ spin_unlock(&mm->page_table_lock);
+
+ if (!numa)
+ return 0;
+
+ /* we're in a page fault so some vma must be in the range */
+ BUG_ON(!vma);
+ BUG_ON(vma->vm_start >= _addr + PMD_SIZE);
+ offset = max(_addr, vma->vm_start) & ~PMD_MASK;
+ VM_BUG_ON(offset >= PMD_SIZE);
+ orig_pte = pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl);
+ pte += offset >> PAGE_SHIFT;
+ for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) {
+ pte_t pteval = *pte;
+ struct page *page;
+ int curr_nid = local_nid;
+ int target_nid;
+ bool migrated;
+ if (!pte_present(pteval))
+ continue;
+ if (!pte_numa(pteval))
+ continue;
+ if (addr >= vma->vm_end) {
+ vma = find_vma(mm, addr);
+ /* there's a pte present so there must be a vma */
+ BUG_ON(!vma);
+ BUG_ON(addr < vma->vm_start);
+ }
+ if (pte_numa(pteval)) {
+ pteval = pte_mknonnuma(pteval);
+ set_pte_at(mm, addr, pte, pteval);
+ }
+ page = vm_normal_page(vma, addr, pteval);
+ if (unlikely(!page))
+ continue;
+ /* only check non-shared pages */
+ if (unlikely(page_mapcount(page) != 1))
+ continue;
+
+ /*
+ * Note that the NUMA fault is later accounted to either
+ * the node that is currently running or where the page is
+ * migrated to.
+ */
+ curr_nid = local_nid;
+ target_nid = numa_migrate_prep(page, vma, addr,
+ page_to_nid(page));
+ if (target_nid == -1) {
+ put_page(page);
+ continue;
+ }
+
+ /* Migrate to the requested node */
+ pte_unmap_unlock(pte, ptl);
+ migrated = migrate_misplaced_page(page, target_nid);
+ if (migrated)
+ curr_nid = target_nid;
+ task_numa_fault(curr_nid, 1, migrated);
+
+ pte = pte_offset_map_lock(mm, pmdp, addr, &ptl);
+ }
+ pte_unmap_unlock(orig_pte, ptl);
+
+ return 0;
+}
+#else
+static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long addr, pmd_t *pmdp)
+{
+ BUG();
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
/*
* These routines also need to handle stuff like marking pages dirty
* and/or accessed for architectures that don't do it in hardware (most
@@ -3450,6 +3631,9 @@ int handle_pte_fault(struct mm_struct *mm,
pte, pmd, flags, entry);
}
+ if (pte_numa(entry))
+ return do_numa_page(mm, vma, address, entry, pte, pmd);
+
ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
if (unlikely(!pte_same(*pte, entry)))
@@ -3520,8 +3704,11 @@ retry:
if (pmd_trans_huge(orig_pmd)) {
unsigned int dirty = flags & FAULT_FLAG_WRITE;
- if (dirty && !pmd_write(orig_pmd) &&
- !pmd_trans_splitting(orig_pmd)) {
+ if (pmd_numa(orig_pmd))
+ return do_huge_pmd_numa_page(mm, vma, address,
+ orig_pmd, pmd);
+
+ if (dirty && !pmd_write(orig_pmd)) {
ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
orig_pmd);
/*
@@ -3536,16 +3723,21 @@ retry:
huge_pmd_set_accessed(mm, vma, address, pmd,
orig_pmd, dirty);
}
+
return 0;
}
}
+ if (pmd_numa(*pmd))
+ return do_pmd_numa_page(mm, vma, address, pmd);
+
/*
* Use __pte_alloc instead of pte_alloc_map, because we can't
* run pte_offset_map on the pmd, if an huge pmd could
* materialize from under us from a different thread.
*/
- if (unlikely(pmd_none(*pmd)) && __pte_alloc(mm, vma, pmd, address))
+ if (unlikely(pmd_none(*pmd)) &&
+ unlikely(__pte_alloc(mm, vma, pmd, address)))
return VM_FAULT_OOM;
/* if an huge pmd materialized from under us just retry later */
if (unlikely(pmd_trans_huge(*pmd)))