kernel.git/mm/truncate.c, branch linux-4.20.y

mm: cleancache: fix corruption on missed inode invalidation

2018-11-30T22:56:14Z

If all pages are deleted from the mapping by memory reclaim and also moved to the cleancache: __delete_from_page_cache (no shadow case) unaccount_page_cache_page cleancache_put_page page_cache_delete mapping->nrpages -= nr (nrpages becomes 0) We don't clean the cleancache for an inode after final file truncation (removal). truncate_inode_pages_final check (nrpages || nrexceptional) is false no truncate_inode_pages no cleancache_invalidate_inode(mapping) These way when reading the new file created with same inode we may get these trash leftover pages from cleancache and see wrong data instead of the contents of the new file. Fix it by always doing truncate_inode_pages which is already ready for nrpages == 0 && nrexceptional == 0 case and just invalidates inode. [akpm@linux-foundation.org: add comment, per Jan] Link: http://lkml.kernel.org/r/20181112095734.17979-1-ptikhomirov@virtuozzo.com Fixes: commit 91b0abe36a7b ("mm + fs: store shadow entries in page cache") Signed-off-by: Pavel Tikhomirov Reviewed-by: Vasily Averin Reviewed-by: Andrey Ryabinin Reviewed-by: Jan Kara Cc: Johannes Weiner Cc: Mel Gorman Cc: Matthew Wilcox Cc: Andi Kleen Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: Convert truncate to XArray

2018-10-21T14:46:37Z

This is essentially xa_cmpxchg() with the locking handled above us, and it doesn't have to handle replacing a NULL entry. Signed-off-by: Matthew Wilcox

xarray: Replace exceptional entries

2018-09-30T02:47:49Z

Introduce xarray value entries and tagged pointers to replace radix tree exceptional entries. This is a slight change in encoding to allow the use of an extra bit (we can now store BITS_PER_LONG - 1 bits in a value entry). It is also a change in emphasis; exceptional entries are intimidating and different. As the comment explains, you can choose to store values or pointers in the xarray and they are both first-class citizens. Signed-off-by: Matthew Wilcox Reviewed-by: Josef Bacik

page cache: use xa_lock

2018-04-11T17:28:39Z

Remove the address_space ->tree_lock and use the xa_lock newly added to the radix_tree_root. Rename the address_space ->page_tree to ->i_pages, since we don't really care that it's a tree. [willy@infradead.org: fix nds32, fs/dax.c] Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org Signed-off-by: Matthew Wilcox Acked-by: Jeff Layton Cc: Darrick J. Wong Cc: Dave Chinner Cc: Ryusuke Konishi Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: add unmap_mapping_pages()

2018-02-01T01:18:37Z

Several users of unmap_mapping_range() would prefer to express their range in pages rather than bytes. Unfortuately, on a 32-bit kernel, you have to remember to cast your page number to a 64-bit type before shifting it, and four places in the current tree didn't remember to do that. That's a sign of a bad interface. Conveniently, unmap_mapping_range() actually converts from bytes into pages, so hoist the guts of unmap_mapping_range() into a new function unmap_mapping_pages() and convert the callers which want to use pages. Link: http://lkml.kernel.org/r/20171206142627.GD32044@bombadil.infradead.org Signed-off-by: Matthew Wilcox Reported-by: "zhangyi (F)" Reviewed-by: Ross Zwisler Acked-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, pagevec: remove cold parameter for pagevecs

2017-11-16T02:21:06Z

Every pagevec_init user claims the pages being released are hot even in cases where it is unlikely the pages are hot. As no one cares about the hotness of pages being released to the allocator, just ditch the parameter. No performance impact is expected as the overhead is marginal. The parameter is removed simply because it is a bit stupid to have a useless parameter copied everywhere. Link: http://lkml.kernel.org/r/20171018075952.10627-6-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Andi Kleen Cc: Dave Chinner Cc: Dave Hansen Cc: Jan Kara Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, truncate: remove all exceptional entries from pagevec under one lock

2017-11-16T02:21:06Z

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% [jack@suse.cz: fix truncate_exceptional_pvec_entries()] Link: http://lkml.kernel.org/r/20171108164226.26788-1-jack@suse.cz Link: http://lkml.kernel.org/r/20171018075952.10627-4-mgorman@techsingularity.net Signed-off-by: Mel Gorman Signed-off-by: Jan Kara Reviewed-by: Jan Kara Acked-by: Johannes Weiner Cc: Andi Kleen Cc: Dave Chinner Cc: Dave Hansen Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, truncate: do not check mapping for every page being truncated

2017-11-16T02:21:06Z

During truncation, the mapping has already been checked for shmem and dax so it's known that workingset_update_node is required. This patch avoids the checks on mapping for each page being truncated. In all other cases, a lookup helper is used to determine if workingset_update_node() needs to be called. The one danger is that the API is slightly harder to use as calling workingset_update_node directly without checking for dax or shmem mappings could lead to surprises. However, the API rarely needs to be used and hopefully the comment is enough to give people the hint. sparsetruncate (tiny) 4.14.0-rc4 4.14.0-rc4 oneirq-v1r1 pickhelper-v1r1 Min Time 141.00 ( 0.00%) 140.00 ( 0.71%) 1st-qrtle Time 142.00 ( 0.00%) 141.00 ( 0.70%) 2nd-qrtle Time 142.00 ( 0.00%) 142.00 ( 0.00%) 3rd-qrtle Time 143.00 ( 0.00%) 143.00 ( 0.00%) Max-90% Time 144.00 ( 0.00%) 144.00 ( 0.00%) Max-95% Time 147.00 ( 0.00%) 145.00 ( 1.36%) Max-99% Time 195.00 ( 0.00%) 191.00 ( 2.05%) Max Time 230.00 ( 0.00%) 205.00 ( 10.87%) Amean Time 144.37 ( 0.00%) 143.82 ( 0.38%) Stddev Time 10.44 ( 0.00%) 9.00 ( 13.74%) Coeff Time 7.23 ( 0.00%) 6.26 ( 13.41%) Best99%Amean Time 143.72 ( 0.00%) 143.34 ( 0.26%) Best95%Amean Time 142.37 ( 0.00%) 142.00 ( 0.26%) Best90%Amean Time 142.19 ( 0.00%) 141.85 ( 0.24%) Best75%Amean Time 141.92 ( 0.00%) 141.58 ( 0.24%) Best50%Amean Time 141.69 ( 0.00%) 141.31 ( 0.27%) Best25%Amean Time 141.38 ( 0.00%) 140.97 ( 0.29%) As you'd expect, the gain is marginal but it can be detected. The differences in bonnie are all within the noise which is not surprising given the impact on the microbenchmark. radix_tree_update_node_t is a callback for some radix operations that optionally passes in a private field. The only user of the callback is workingset_update_node and as it no longer requires a mapping, the private field is removed. Link: http://lkml.kernel.org/r/20171018075952.10627-3-mgorman@techsingularity.net Signed-off-by: Mel Gorman Acked-by: Johannes Weiner Reviewed-by: Jan Kara Cc: Andi Kleen Cc: Dave Chinner Cc: Dave Hansen Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: batch radix tree operations when truncating pages

2017-11-16T02:21:06Z

Currently we remove pages from the radix tree one by one. To speed up page cache truncation, lock several pages at once and free them in one go. This allows us to batch radix tree operations in a more efficient way and also save round-trips on mapping->tree_lock. As a result we gain about 20% speed improvement in page cache truncation. Data from a simple benchmark timing 10000 truncates of 1024 pages (on ext4 on ramdisk but the filesystem is barely visible in the profiles). The range shows 1% and 95% percentiles of the measured times: 4.14-rc2 4.14-rc2 + batched truncation 248-256 209-219 249-258 209-217 248-255 211-239 248-255 209-217 247-256 210-218 [jack@suse.cz: convert delete_from_page_cache_batch() to pagevec] Link: http://lkml.kernel.org/r/20171018111648.13714-1-jack@suse.cz [akpm@linux-foundation.org: move struct pagevec forward declaration to top-of-file] Link: http://lkml.kernel.org/r/20171010151937.26984-8-jack@suse.cz Signed-off-by: Jan Kara Acked-by: Mel Gorman Reviewed-by: Andi Kleen Cc: Dave Chinner Cc: Dave Hansen Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: refactor truncate_complete_page()

2017-11-16T02:21:06Z

Move call of delete_from_page_cache() and page->mapping check out of truncate_complete_page() into the single caller - truncate_inode_page(). Also move page_mapped() check into truncate_complete_page(). That way it will be easier to batch operations. Also rename truncate_complete_page() to truncate_cleanup_page(). Link: http://lkml.kernel.org/r/20171010151937.26984-3-jack@suse.cz Signed-off-by: Jan Kara Acked-by: Mel Gorman Reviewed-by: Andi Kleen Cc: Dave Chinner Cc: Dave Hansen Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds