From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754715Ab2KUK1T (ORCPT ); Wed, 21 Nov 2012 05:27:19 -0500 Received: from cantor2.suse.de ([195.135.220.15]:43901 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754313Ab2KUKWn (ORCPT ); Wed, 21 Nov 2012 05:22:43 -0500 From: Mel Gorman To: Peter Zijlstra , Andrea Arcangeli , Ingo Molnar Cc: Rik van Riel , Johannes Weiner , Hugh Dickins , Thomas Gleixner , Paul Turner , Lee Schermerhorn , Alex Shi , Linus Torvalds , Andrew Morton , Linux-MM , LKML , Mel Gorman Subject: [PATCH 28/46] mm: numa: Add pte updates, hinting and migration stats Date: Wed, 21 Nov 2012 10:21:34 +0000 Message-Id: <1353493312-8069-29-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1353493312-8069-1-git-send-email-mgorman@suse.de> References: <1353493312-8069-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is tricky to quantify the basic cost of automatic NUMA placement in a meaningful manner. This patch adds some vmstats that can be used as part of a basic costing model. u = basic unit = sizeof(void *) Ca = cost of struct page access = sizeof(struct page) / u Cpte = Cost PTE access = Ca Cupdate = Cost PTE update = (2 * Cpte) + (2 * Wlock) where Cpte is incurred twice for a read and a write and Wlock is a constant representing the cost of taking or releasing a lock Cnumahint = Cost of a minor page fault = some high constant e.g. 1000 Cpagerw = Cost to read or write a full page = Ca + PAGE_SIZE/u Ci = Cost of page isolation = Ca + Wi where Wi is a constant that should reflect the approximate cost of the locking operation Cpagecopy = Cpagerw + (Cpagerw * Wnuma) + Ci + (Ci * Wnuma) where Wnuma is the approximate NUMA factor. 1 is local. 1.2 would imply that remote accesses are 20% more expensive Balancing cost = Cpte * numa_pte_updates + Cnumahint * numa_hint_faults + Ci * numa_pages_migrated + Cpagecopy * numa_pages_migrated Note that numa_pages_migrated is used as a measure of how many pages were isolated even though it would miss pages that failed to migrate. A vmstat counter could have been added for it but the isolation cost is pretty marginal in comparison to the overall cost so it seemed overkill. The ideal way to measure automatic placement benefit would be to count the number of remote accesses versus local accesses and do something like benefit = (remote_accesses_before - remove_access_after) * Wnuma but the information is not readily available. As a workload converges, the expection would be that the number of remote numa hints would reduce to 0. convergence = numa_hint_faults_local / numa_hint_faults where this is measured for the last N number of numa hints recorded. When the workload is fully converged the value is 1. This can measure if the placement policy is converging and how fast it is doing it. Signed-off-by: Mel Gorman Acked-by: Rik van Riel --- include/linux/vm_event_item.h | 6 ++++++ include/linux/vmstat.h | 8 ++++++++ mm/huge_memory.c | 1 + mm/memory.c | 12 ++++++++++++ mm/mempolicy.c | 2 ++ mm/migrate.c | 3 ++- mm/vmstat.c | 6 ++++++ 7 files changed, 37 insertions(+), 1 deletion(-) diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index a1f750b..dded0af 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -38,6 +38,12 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY, KSWAPD_SKIP_CONGESTION_WAIT, PAGEOUTRUN, ALLOCSTALL, PGROTATED, +#ifdef CONFIG_BALANCE_NUMA + NUMA_PTE_UPDATES, + NUMA_HINT_FAULTS, + NUMA_HINT_FAULTS_LOCAL, + NUMA_PAGE_MIGRATE, +#endif #ifdef CONFIG_MIGRATION PGMIGRATE_SUCCESS, PGMIGRATE_FAIL, #endif diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index 92a86b2..dffccfa 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -80,6 +80,14 @@ static inline void vm_events_fold_cpu(int cpu) #endif /* CONFIG_VM_EVENT_COUNTERS */ +#ifdef CONFIG_BALANCE_NUMA +#define count_vm_numa_event(x) count_vm_event(x) +#define count_vm_numa_events(x, y) count_vm_events(x, y) +#else +#define count_vm_numa_event(x) do {} while (0) +#define count_vm_numa_events(x, y) do {} while (0) +#endif /* CONFIG_BALANCE_NUMA */ + #define __count_zone_vm_events(item, zone, delta) \ __count_vm_events(item##_NORMAL - ZONE_NORMAL + \ zone_idx(zone), delta) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b3d4c4b..8f89a98 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1033,6 +1033,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, page = pmd_page(pmd); get_page(page); spin_unlock(&mm->page_table_lock); + count_vm_numa_event(NUMA_HINT_FAULTS); target_nid = mpol_misplaced(page, vma, haddr); if (target_nid == -1) diff --git a/mm/memory.c b/mm/memory.c index b23b081..8367142 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3477,6 +3477,7 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, set_pte_at(mm, addr, ptep, pte); update_mmu_cache(vma, addr, ptep); + count_vm_numa_event(NUMA_HINT_FAULTS); page = vm_normal_page(vma, addr, pte); if (!page) { pte_unmap_unlock(ptep, ptl); @@ -3485,6 +3486,8 @@ int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, get_page(page); current_nid = page_to_nid(page); + if (current_nid == numa_node_id()) + count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); target_nid = mpol_misplaced(page, vma, addr); pte_unmap_unlock(ptep, ptl); if (target_nid == -1) { @@ -3516,6 +3519,9 @@ int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long offset; spinlock_t *ptl; bool numa = false; + int local_nid = numa_node_id(); + unsigned long nr_faults = 0; + unsigned long nr_faults_local = 0; spin_lock(&mm->page_table_lock); pmd = *pmdp; @@ -3564,10 +3570,16 @@ int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, curr_nid = page_to_nid(page); task_numa_fault(curr_nid, 1); + nr_faults++; + if (curr_nid == local_nid) + nr_faults_local++; + pte = pte_offset_map_lock(mm, pmdp, addr, &ptl); } pte_unmap_unlock(orig_pte, ptl); + count_vm_numa_events(NUMA_HINT_FAULTS, nr_faults); + count_vm_numa_events(NUMA_HINT_FAULTS_LOCAL, nr_faults_local); return 0; } diff --git a/mm/mempolicy.c b/mm/mempolicy.c index a7a62fe..516491f 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -583,6 +583,8 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, BUILD_BUG_ON(_PAGE_NUMA != _PAGE_PROTNONE); nr_updated = change_protection(vma, addr, end, vma->vm_page_prot, 0, 1); + if (nr_updated) + count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated); return nr_updated; } diff --git a/mm/migrate.c b/mm/migrate.c index a2c4567..4b876d2 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1511,7 +1511,8 @@ int migrate_misplaced_page(struct page *page, int node) if (nr_remaining) { putback_lru_pages(&migratepages); isolated = 0; - } + } else + count_vm_numa_event(NUMA_PAGE_MIGRATE); } BUG_ON(!list_empty(&migratepages)); out: diff --git a/mm/vmstat.c b/mm/vmstat.c index 3a067fa..cfa386da 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -774,6 +774,12 @@ const char * const vmstat_text[] = { "pgrotated", +#ifdef CONFIG_BALANCE_NUMA + "numa_pte_updates", + "numa_hint_faults", + "numa_hint_faults_local", + "numa_pages_migrated", +#endif #ifdef CONFIG_MIGRATION "pgmigrate_success", "pgmigrate_fail", -- 1.7.9.2