From: Mel Gorman <mgorman@techsingularity.net> To: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-MM <linux-mm@kvack.org>, Linux-FSDevel <linux-fsdevel@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Jan Kara <jack@suse.cz>, Andi Kleen <ak@linux.intel.com>, Dave Hansen <dave.hansen@intel.com>, Dave Chinner <david@fromorbit.com>, Mel Gorman <mgorman@techsingularity.net> Subject: [PATCH 3/8] mm, truncate: Remove all exceptional entries from pagevec under one lock Date: Wed, 18 Oct 2017 08:59:47 +0100 [thread overview] Message-ID: <20171018075952.10627-4-mgorman@techsingularity.net> (raw) In-Reply-To: <20171018075952.10627-1-mgorman@techsingularity.net> During truncate each entry in a pagevec is checked to see if it is an exceptional entry and if so, the shadow entry is cleaned up. This is potentially expensive as multiple entries for a mapping locks/unlocks the tree lock. This batches the operation such that any exceptional entries removed from a pagevec only acquire the mapping tree lock once. The corner case where this is more expensive is where there is only one exceptional entry but this is unlikely due to temporal locality and how it affects LRU ordering. Note that for truncations of small files created recently, this patch should show no gain because it only batches the handling of exceptional entries. sparsetruncate (large) 4.14.0-rc4 4.14.0-rc4 pickhelper-v1r1 batchshadow-v1r1 Min Time 38.00 ( 0.00%) 27.00 ( 28.95%) 1st-qrtle Time 40.00 ( 0.00%) 28.00 ( 30.00%) 2nd-qrtle Time 44.00 ( 0.00%) 41.00 ( 6.82%) 3rd-qrtle Time 146.00 ( 0.00%) 147.00 ( -0.68%) Max-90% Time 153.00 ( 0.00%) 153.00 ( 0.00%) Max-95% Time 155.00 ( 0.00%) 156.00 ( -0.65%) Max-99% Time 181.00 ( 0.00%) 171.00 ( 5.52%) Amean Time 93.04 ( 0.00%) 88.43 ( 4.96%) Best99%Amean Time 92.08 ( 0.00%) 86.13 ( 6.46%) Best95%Amean Time 89.19 ( 0.00%) 83.13 ( 6.80%) Best90%Amean Time 85.60 ( 0.00%) 79.15 ( 7.53%) Best75%Amean Time 72.95 ( 0.00%) 65.09 ( 10.78%) Best50%Amean Time 39.86 ( 0.00%) 28.20 ( 29.25%) Best25%Amean Time 39.44 ( 0.00%) 27.70 ( 29.77%) bonnie 4.14.0-rc4 4.14.0-rc4 pickhelper-v1r1 batchshadow-v1r1 Hmean SeqCreate ops 71.92 ( 0.00%) 76.78 ( 6.76%) Hmean SeqCreate read 42.42 ( 0.00%) 45.01 ( 6.10%) Hmean SeqCreate del 26519.88 ( 0.00%) 27191.87 ( 2.53%) Hmean RandCreate ops 71.92 ( 0.00%) 76.95 ( 7.00%) Hmean RandCreate read 44.44 ( 0.00%) 49.23 ( 10.78%) Hmean RandCreate del 24948.62 ( 0.00%) 24764.97 ( -0.74%) Truncation of a large number of files shows a substantial gain with 99% of files being truncated 6.46% faster. bonnie shows a modest gain of 2.53% Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> --- mm/truncate.c | 86 ++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 61 insertions(+), 25 deletions(-) diff --git a/mm/truncate.c b/mm/truncate.c index d578d542a6ee..d1913888edf4 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -25,44 +25,77 @@ #include <linux/rmap.h> #include "internal.h" -static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, - void *entry) +/* + * Regular page slots are stabilized by the page lock even without the tree + * itself locked. These unlocked entries need verification under the tree + * lock. + */ +static inline void __clear_shadow_entry(struct address_space *mapping, + pgoff_t index, void *entry) { struct radix_tree_node *node; void **slot; - spin_lock_irq(&mapping->tree_lock); - /* - * Regular page slots are stabilized by the page lock even - * without the tree itself locked. These unlocked entries - * need verification under the tree lock. - */ if (!__radix_tree_lookup(&mapping->page_tree, index, &node, &slot)) - goto unlock; + return; if (*slot != entry) - goto unlock; + return; __radix_tree_replace(&mapping->page_tree, node, slot, NULL, workingset_update_node); mapping->nrexceptional--; -unlock: +} + +static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, + void *entry) +{ + spin_lock_irq(&mapping->tree_lock); + __clear_shadow_entry(mapping, index, entry); spin_unlock_irq(&mapping->tree_lock); } /* - * Unconditionally remove exceptional entry. Usually called from truncate path. + * Unconditionally remove exceptional entries. Usually called from truncate + * path. Note that the pagevec may be altered by this function by removing + * exceptional entries similar to what pagevec_remove_exceptionals does. */ -static void truncate_exceptional_entry(struct address_space *mapping, - pgoff_t index, void *entry) +static void truncate_exceptional_pvec_entries(struct address_space *mapping, + struct pagevec *pvec, pgoff_t *indices, int ei) { + int i, j; + bool dax; + + /* Return immediately if caller indicates there are no entries */ + if (ei == PAGEVEC_SIZE) + return; + /* Handled by shmem itself */ if (shmem_mapping(mapping)) return; - if (dax_mapping(mapping)) { - dax_delete_mapping_entry(mapping, index); - return; + dax = dax_mapping(mapping); + if (!dax) + spin_lock_irq(&mapping->tree_lock); + + for (i = ei, j = ei; i < pagevec_count(pvec); i++) { + struct page *page = pvec->pages[i]; + pgoff_t index = indices[i]; + + if (!radix_tree_exceptional_entry(page)) { + pvec->pages[j++] = page; + continue; + } + + if (unlikely(dax)) { + dax_delete_mapping_entry(mapping, index); + continue; + } + + __clear_shadow_entry(mapping, index, page); } - clear_shadow_entry(mapping, index, entry); + + if (!dax) + spin_unlock_irq(&mapping->tree_lock); + pvec->nr = j; } /* @@ -301,6 +334,7 @@ void truncate_inode_pages_range(struct address_space *mapping, */ struct page *pages[PAGEVEC_SIZE]; int batch_count = 0; + int ei = PAGEVEC_SIZE; for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; @@ -311,8 +345,8 @@ void truncate_inode_pages_range(struct address_space *mapping, break; if (radix_tree_exceptional_entry(page)) { - truncate_exceptional_entry(mapping, index, - page); + if (ei == PAGEVEC_SIZE) + ei = i; continue; } @@ -334,12 +368,11 @@ void truncate_inode_pages_range(struct address_space *mapping, delete_from_page_cache_batch(mapping, batch_count, pages); for (i = 0; i < batch_count; i++) unlock_page(pages[i]); - pagevec_remove_exceptionals(&pvec); + truncate_exceptional_pvec_entries(mapping, &pvec, indices, ei); pagevec_release(&pvec); cond_resched(); index++; } - if (partial_start) { struct page *page = find_lock_page(mapping, start - 1); if (page) { @@ -381,6 +414,8 @@ void truncate_inode_pages_range(struct address_space *mapping, index = start; for ( ; ; ) { + int ei = PAGEVEC_SIZE; + cond_resched(); if (!pagevec_lookup_entries(&pvec, mapping, index, min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) { @@ -397,6 +432,7 @@ void truncate_inode_pages_range(struct address_space *mapping, pagevec_release(&pvec); break; } + for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; @@ -409,8 +445,8 @@ void truncate_inode_pages_range(struct address_space *mapping, } if (radix_tree_exceptional_entry(page)) { - truncate_exceptional_entry(mapping, index, - page); + if (ei == PAGEVEC_SIZE) + ei = i; continue; } @@ -420,7 +456,7 @@ void truncate_inode_pages_range(struct address_space *mapping, truncate_inode_page(mapping, page); unlock_page(page); } - pagevec_remove_exceptionals(&pvec); + truncate_exceptional_pvec_entries(mapping, &pvec, indices, ei); pagevec_release(&pvec); index++; } -- 2.14.0
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@techsingularity.net> To: Andrew Morton <akpm@linux-foundation.org> Cc: Linux-MM <linux-mm@kvack.org>, Linux-FSDevel <linux-fsdevel@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>, Jan Kara <jack@suse.cz>, Andi Kleen <ak@linux.intel.com>, Dave Hansen <dave.hansen@intel.com>, Dave Chinner <david@fromorbit.com>, Mel Gorman <mgorman@techsingularity.net> Subject: [PATCH 3/8] mm, truncate: Remove all exceptional entries from pagevec under one lock Date: Wed, 18 Oct 2017 08:59:47 +0100 [thread overview] Message-ID: <20171018075952.10627-4-mgorman@techsingularity.net> (raw) In-Reply-To: <20171018075952.10627-1-mgorman@techsingularity.net> During truncate each entry in a pagevec is checked to see if it is an exceptional entry and if so, the shadow entry is cleaned up. This is potentially expensive as multiple entries for a mapping locks/unlocks the tree lock. This batches the operation such that any exceptional entries removed from a pagevec only acquire the mapping tree lock once. The corner case where this is more expensive is where there is only one exceptional entry but this is unlikely due to temporal locality and how it affects LRU ordering. Note that for truncations of small files created recently, this patch should show no gain because it only batches the handling of exceptional entries. sparsetruncate (large) 4.14.0-rc4 4.14.0-rc4 pickhelper-v1r1 batchshadow-v1r1 Min Time 38.00 ( 0.00%) 27.00 ( 28.95%) 1st-qrtle Time 40.00 ( 0.00%) 28.00 ( 30.00%) 2nd-qrtle Time 44.00 ( 0.00%) 41.00 ( 6.82%) 3rd-qrtle Time 146.00 ( 0.00%) 147.00 ( -0.68%) Max-90% Time 153.00 ( 0.00%) 153.00 ( 0.00%) Max-95% Time 155.00 ( 0.00%) 156.00 ( -0.65%) Max-99% Time 181.00 ( 0.00%) 171.00 ( 5.52%) Amean Time 93.04 ( 0.00%) 88.43 ( 4.96%) Best99%Amean Time 92.08 ( 0.00%) 86.13 ( 6.46%) Best95%Amean Time 89.19 ( 0.00%) 83.13 ( 6.80%) Best90%Amean Time 85.60 ( 0.00%) 79.15 ( 7.53%) Best75%Amean Time 72.95 ( 0.00%) 65.09 ( 10.78%) Best50%Amean Time 39.86 ( 0.00%) 28.20 ( 29.25%) Best25%Amean Time 39.44 ( 0.00%) 27.70 ( 29.77%) bonnie 4.14.0-rc4 4.14.0-rc4 pickhelper-v1r1 batchshadow-v1r1 Hmean SeqCreate ops 71.92 ( 0.00%) 76.78 ( 6.76%) Hmean SeqCreate read 42.42 ( 0.00%) 45.01 ( 6.10%) Hmean SeqCreate del 26519.88 ( 0.00%) 27191.87 ( 2.53%) Hmean RandCreate ops 71.92 ( 0.00%) 76.95 ( 7.00%) Hmean RandCreate read 44.44 ( 0.00%) 49.23 ( 10.78%) Hmean RandCreate del 24948.62 ( 0.00%) 24764.97 ( -0.74%) Truncation of a large number of files shows a substantial gain with 99% of files being truncated 6.46% faster. bonnie shows a modest gain of 2.53% Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> --- mm/truncate.c | 86 ++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 61 insertions(+), 25 deletions(-) diff --git a/mm/truncate.c b/mm/truncate.c index d578d542a6ee..d1913888edf4 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -25,44 +25,77 @@ #include <linux/rmap.h> #include "internal.h" -static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, - void *entry) +/* + * Regular page slots are stabilized by the page lock even without the tree + * itself locked. These unlocked entries need verification under the tree + * lock. + */ +static inline void __clear_shadow_entry(struct address_space *mapping, + pgoff_t index, void *entry) { struct radix_tree_node *node; void **slot; - spin_lock_irq(&mapping->tree_lock); - /* - * Regular page slots are stabilized by the page lock even - * without the tree itself locked. These unlocked entries - * need verification under the tree lock. - */ if (!__radix_tree_lookup(&mapping->page_tree, index, &node, &slot)) - goto unlock; + return; if (*slot != entry) - goto unlock; + return; __radix_tree_replace(&mapping->page_tree, node, slot, NULL, workingset_update_node); mapping->nrexceptional--; -unlock: +} + +static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, + void *entry) +{ + spin_lock_irq(&mapping->tree_lock); + __clear_shadow_entry(mapping, index, entry); spin_unlock_irq(&mapping->tree_lock); } /* - * Unconditionally remove exceptional entry. Usually called from truncate path. + * Unconditionally remove exceptional entries. Usually called from truncate + * path. Note that the pagevec may be altered by this function by removing + * exceptional entries similar to what pagevec_remove_exceptionals does. */ -static void truncate_exceptional_entry(struct address_space *mapping, - pgoff_t index, void *entry) +static void truncate_exceptional_pvec_entries(struct address_space *mapping, + struct pagevec *pvec, pgoff_t *indices, int ei) { + int i, j; + bool dax; + + /* Return immediately if caller indicates there are no entries */ + if (ei == PAGEVEC_SIZE) + return; + /* Handled by shmem itself */ if (shmem_mapping(mapping)) return; - if (dax_mapping(mapping)) { - dax_delete_mapping_entry(mapping, index); - return; + dax = dax_mapping(mapping); + if (!dax) + spin_lock_irq(&mapping->tree_lock); + + for (i = ei, j = ei; i < pagevec_count(pvec); i++) { + struct page *page = pvec->pages[i]; + pgoff_t index = indices[i]; + + if (!radix_tree_exceptional_entry(page)) { + pvec->pages[j++] = page; + continue; + } + + if (unlikely(dax)) { + dax_delete_mapping_entry(mapping, index); + continue; + } + + __clear_shadow_entry(mapping, index, page); } - clear_shadow_entry(mapping, index, entry); + + if (!dax) + spin_unlock_irq(&mapping->tree_lock); + pvec->nr = j; } /* @@ -301,6 +334,7 @@ void truncate_inode_pages_range(struct address_space *mapping, */ struct page *pages[PAGEVEC_SIZE]; int batch_count = 0; + int ei = PAGEVEC_SIZE; for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; @@ -311,8 +345,8 @@ void truncate_inode_pages_range(struct address_space *mapping, break; if (radix_tree_exceptional_entry(page)) { - truncate_exceptional_entry(mapping, index, - page); + if (ei == PAGEVEC_SIZE) + ei = i; continue; } @@ -334,12 +368,11 @@ void truncate_inode_pages_range(struct address_space *mapping, delete_from_page_cache_batch(mapping, batch_count, pages); for (i = 0; i < batch_count; i++) unlock_page(pages[i]); - pagevec_remove_exceptionals(&pvec); + truncate_exceptional_pvec_entries(mapping, &pvec, indices, ei); pagevec_release(&pvec); cond_resched(); index++; } - if (partial_start) { struct page *page = find_lock_page(mapping, start - 1); if (page) { @@ -381,6 +414,8 @@ void truncate_inode_pages_range(struct address_space *mapping, index = start; for ( ; ; ) { + int ei = PAGEVEC_SIZE; + cond_resched(); if (!pagevec_lookup_entries(&pvec, mapping, index, min(end - index, (pgoff_t)PAGEVEC_SIZE), indices)) { @@ -397,6 +432,7 @@ void truncate_inode_pages_range(struct address_space *mapping, pagevec_release(&pvec); break; } + for (i = 0; i < pagevec_count(&pvec); i++) { struct page *page = pvec.pages[i]; @@ -409,8 +445,8 @@ void truncate_inode_pages_range(struct address_space *mapping, } if (radix_tree_exceptional_entry(page)) { - truncate_exceptional_entry(mapping, index, - page); + if (ei == PAGEVEC_SIZE) + ei = i; continue; } @@ -420,7 +456,7 @@ void truncate_inode_pages_range(struct address_space *mapping, truncate_inode_page(mapping, page); unlock_page(page); } - pagevec_remove_exceptionals(&pvec); + truncate_exceptional_pvec_entries(mapping, &pvec, indices, ei); pagevec_release(&pvec); index++; } -- 2.14.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-10-18 8:00 UTC|newest] Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-18 7:59 [PATCH 0/8] Follow-up for speed up page cache truncation v2 Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-18 7:59 ` [PATCH 1/8] mm, page_alloc: Enable/disable IRQs once when freeing a list of pages Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-18 9:02 ` Vlastimil Babka 2017-10-18 9:02 ` Vlastimil Babka 2017-10-18 10:15 ` Mel Gorman 2017-10-18 10:15 ` Mel Gorman 2017-10-18 7:59 ` [PATCH 2/8] mm, truncate: Do not check mapping for every page being truncated Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-19 8:11 ` Jan Kara 2017-10-19 8:11 ` Jan Kara 2017-10-18 7:59 ` Mel Gorman [this message] 2017-10-18 7:59 ` [PATCH 3/8] mm, truncate: Remove all exceptional entries from pagevec under one lock Mel Gorman 2017-10-18 7:59 ` [PATCH 4/8] mm: Only drain per-cpu pagevecs once per pagevec usage Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-19 9:12 ` Vlastimil Babka 2017-10-19 9:12 ` Vlastimil Babka 2017-10-19 9:33 ` Mel Gorman 2017-10-19 9:33 ` Mel Gorman 2017-10-19 13:21 ` Vlastimil Babka 2017-10-19 13:21 ` Vlastimil Babka 2017-10-18 7:59 ` [PATCH 5/8] mm, pagevec: Remove cold parameter for pagevecs Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-19 9:24 ` Vlastimil Babka 2017-10-19 9:24 ` Vlastimil Babka 2017-10-18 7:59 ` [PATCH 6/8] mm: Remove cold parameter for release_pages Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-19 9:26 ` Vlastimil Babka 2017-10-19 9:26 ` Vlastimil Babka 2017-10-18 7:59 ` [PATCH 7/8] mm, Remove cold parameter from free_hot_cold_page* Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-19 13:12 ` Vlastimil Babka 2017-10-19 13:12 ` Vlastimil Babka 2017-10-19 15:43 ` Mel Gorman 2017-10-19 15:43 ` Mel Gorman 2017-10-18 7:59 ` [PATCH 8/8] mm: Remove __GFP_COLD Mel Gorman 2017-10-18 7:59 ` Mel Gorman 2017-10-19 13:18 ` Vlastimil Babka 2017-10-19 13:18 ` Vlastimil Babka 2017-10-19 13:42 ` Vlastimil Babka 2017-10-19 13:42 ` Vlastimil Babka 2017-10-19 13:42 ` Vlastimil Babka 2017-10-19 14:32 ` Mel Gorman 2017-10-19 14:32 ` Mel Gorman -- strict thread matches above, loose matches on Subject: below -- 2017-10-12 9:30 [PATCH 0/8] Follow-up for speed up page cache truncation Mel Gorman 2017-10-12 9:30 ` [PATCH 3/8] mm, truncate: Remove all exceptional entries from pagevec under one lock Mel Gorman 2017-10-12 9:30 ` Mel Gorman 2017-10-12 13:33 ` Jan Kara 2017-10-12 13:33 ` Jan Kara 2017-10-12 14:53 ` Mel Gorman 2017-10-12 14:53 ` Mel Gorman 2017-10-12 19:45 ` Johannes Weiner 2017-10-12 19:45 ` Johannes Weiner
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