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2016-08-26mm: silently skip readahead for DAX inodesRoss Zwisler1-0/+9
For DAX inodes we need to be careful to never have page cache pages in the mapping->page_tree. This radix tree should be composed only of DAX exceptional entries and zero pages. ltp's readahead02 test was triggering a warning because we were trying to insert a DAX exceptional entry but found that a page cache page had already been inserted into the tree. This page was being inserted into the radix tree in response to a readahead(2) call. Readahead doesn't make sense for DAX inodes, but we don't want it to report a failure either. Instead, we just return success and don't do any work. Link: http://lkml.kernel.org/r/20160824221429.21158-1-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: Jeff Moyer <jmoyer@redhat.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jan Kara <jack@suse.com> Cc: <stable@vger.kernel.org> [4.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26mm, memcg: use consistent gfp flags during readaheadMichal Hocko1-7/+6
Vladimir has noticed that we might declare memcg oom even during readahead because read_pages only uses GFP_KERNEL (with mapping_gfp restriction) while __do_page_cache_readahead uses page_cache_alloc_readahead which adds __GFP_NORETRY to prevent from OOMs. This gfp mask discrepancy is really unfortunate and easily fixable. Drop page_cache_alloc_readahead() which only has one user and outsource the gfp_mask logic into readahead_gfp_mask and propagate this mask from __do_page_cache_readahead down to read_pages. This alone would have only very limited impact as most filesystems are implementing ->readpages and the common implementation mpage_readpages does GFP_KERNEL (with mapping_gfp restriction) again. We can tell it to use readahead_gfp_mask instead as this function is called only during readahead as well. The same applies to read_cache_pages. ext4 has its own ext4_mpage_readpages but the path which has pages != NULL can use the same gfp mask. Btrfs, cifs, f2fs and orangefs are doing a very similar pattern to mpage_readpages so the same can be applied to them as well. [akpm@linux-foundation.org: coding-style fixes] [mhocko@suse.com: restrict gfp mask in mpage_alloc] Link: http://lkml.kernel.org/r/20160610074223.GC32285@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1465301556-26431-1-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Chris Mason <clm@fb.com> Cc: Steve French <sfrench@samba.org> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Jan Kara <jack@suse.cz> Cc: Mike Marshall <hubcap@omnibond.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Changman Lee <cm224.lee@samsung.com> Cc: Chao Yu <yuchao0@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-10/+10
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14mm: move lru_to_page to mm_inline.hGeliang Tang1-0/+1
Move lru_to_page() from internal.h to mm_inline.h. Signed-off-by: Geliang Tang <geliangtang@163.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14mm/readahead.c, mm/vmscan.c: use lru_to_page instead of list_to_pageGeliang Tang1-5/+3
list_to_page() in readahead.c is the same as lru_to_page() in vmscan.c. So I move lru_to_page to internal.h and drop list_to_page(). Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06mm, fs: introduce mapping_gfp_constraint()Michal Hocko1-2/+2
There are many places which use mapping_gfp_mask to restrict a more generic gfp mask which would be used for allocations which are not directly related to the page cache but they are performed in the same context. Let's introduce a helper function which makes the restriction explicit and easier to track. This patch doesn't introduce any functional changes. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-05mm: use only per-device readahead limitRoman Gushchin1-12/+2
Maximal readahead size is limited now by two values: 1) by global 2Mb constant (MAX_READAHEAD in max_sane_readahead()) 2) by configurable per-device value* (bdi->ra_pages) There are devices, which require custom readahead limit. For instance, for RAIDs it's calculated as number of devices multiplied by chunk size times 2. Readahead size can never be larger than bdi->ra_pages * 2 value (POSIX_FADV_SEQUNTIAL doubles readahead size). If so, why do we need two limits? I suggest to completely remove this max_sane_readahead() stuff and use per-device readahead limit everywhere. Also, using right readahead size for RAID disks can significantly increase i/o performance: before: dd if=/dev/md2 of=/dev/null bs=100M count=100 100+0 records in 100+0 records out 10485760000 bytes (10 GB) copied, 12.9741 s, 808 MB/s after: $ dd if=/dev/md2 of=/dev/null bs=100M count=100 100+0 records in 100+0 records out 10485760000 bytes (10 GB) copied, 8.91317 s, 1.2 GB/s (It's an 8-disks RAID5 storage). This patch doesn't change sys_readahead and madvise(MADV_WILLNEED) behavior introduced by 6d2be915e589b58 ("mm/readahead.c: fix readahead failure for memoryless NUMA nodes and limit readahead pages"). Signed-off-by: Roman Gushchin <klamm@yandex-team.ru> Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Cc: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: onstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-16mm, fs: obey gfp_mapping for add_to_page_cache()Michal Hocko1-4/+4
Commit 6afdb859b710 ("mm: do not ignore mapping_gfp_mask in page cache allocation paths") has caught some users of hardcoded GFP_KERNEL used in the page cache allocation paths. This, however, wasn't complete and there were others which went unnoticed. Dave Chinner has reported the following deadlock for xfs on loop device: : With the recent merge of the loop device changes, I'm now seeing : XFS deadlock on my single CPU, 1GB RAM VM running xfs/073. : : The deadlocked is as follows: : : kloopd1: loop_queue_read_work : xfs_file_iter_read : lock XFS inode XFS_IOLOCK_SHARED (on image file) : page cache read (GFP_KERNEL) : radix tree alloc : memory reclaim : reclaim XFS inodes : log force to unpin inodes : <wait for log IO completion> : : xfs-cil/loop1: <does log force IO work> : xlog_cil_push : xlog_write : <loop issuing log writes> : xlog_state_get_iclog_space() : <blocks due to all log buffers under write io> : <waits for IO completion> : : kloopd1: loop_queue_write_work : xfs_file_write_iter : lock XFS inode XFS_IOLOCK_EXCL (on image file) : <wait for inode to be unlocked> : : i.e. the kloopd, with it's split read and write work queues, has : introduced a dependency through memory reclaim. i.e. that writes : need to be able to progress for reads make progress. : : The problem, fundamentally, is that mpage_readpages() does a : GFP_KERNEL allocation, rather than paying attention to the inode's : mapping gfp mask, which is set to GFP_NOFS. : : The didn't used to happen, because the loop device used to issue : reads through the splice path and that does: : : error = add_to_page_cache_lru(page, mapping, index, : GFP_KERNEL & mapping_gfp_mask(mapping)); This has changed by commit aa4d86163e4 ("block: loop: switch to VFS ITER_BVEC"). This patch changes mpage_readpage{s} to follow gfp mask set for the mapping. There are, however, other places which are doing basically the same. lustre:ll_dir_filler is doing GFP_KERNEL from the function which apparently uses GFP_NOFS for other allocations so let's make this consistent. cifs:readpages_get_pages is called from cifs_readpages and __cifs_readpages_from_fscache called from the same path obeys mapping gfp. ramfs_nommu_expand_for_mapping is hardcoding GFP_KERNEL as well regardless it uses mapping_gfp_mask for the page allocation. ext4_mpage_readpages is the called from the page cache allocation path same as read_pages and read_cache_pages As I've noticed in my previous post I cannot say I would be happy about sprinkling mapping_gfp_mask all over the place and it sounds like we should drop gfp_mask argument altogether and use it internally in __add_to_page_cache_locked that would require all the filesystems to use mapping gfp consistently which I am not sure is the case here. From a quick glance it seems that some file system use it all the time while others are selective. Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Dave Chinner <david@fromorbit.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Ming Lei <ming.lei@canonical.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-02writeback: implement and use inode_congested()Tejun Heo1-1/+1
In several places, bdi_congested() and its wrappers are used to determine whether more IOs should be issued. With cgroup writeback support, this question can't be answered solely based on the bdi (backing_dev_info). It's dependent on whether the filesystem and bdi support cgroup writeback and the blkcg the inode is associated with. This patch implements inode_congested() and its wrappers which take @inode and determines the congestion state considering cgroup writeback. The new functions replace bdi_*congested() calls in places where the query is about specific inode and task. There are several filesystem users which also fit this criteria but they should be updated when each filesystem implements cgroup writeback support. v2: Now that a given inode is associated with only one wb, congestion state can be determined independent from the asking task. Drop @task. Spotted by Vivek. Also, converted to take @inode instead of @mapping and renamed to inode_congested(). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Jan Kara <jack@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-01-20fs: export inode_to_bdi and use it in favor of mapping->backing_dev_infoChristoph Hellwig1-2/+2
Now that we got rid of the bdi abuse on character devices we can always use sb->s_bdi to get at the backing_dev_info for a file, except for the block device special case. Export inode_to_bdi and replace uses of mapping->backing_dev_info with it to prepare for the removal of mapping->backing_dev_info. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-08-06mm/readahead.c: remove unused file_ra_state from count_history_pagesFabian Frederick1-2/+1
count_history_pages does only call page_cache_prev_hole in rcu_lock context using address_space mapping. There's no need to have file_ra_state here. Signed-off-by: Fabian Frederick <fabf@skynet.be> Acked-by: Fengguang Wu <fengguang.wu@intel.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07mm/readahead.c: inline ra_submitFabian Frederick1-18/+3
Commit f9acc8c7b35a ("readahead: sanify file_ra_state names") left ra_submit with a single function call. Move ra_submit to internal.h and inline it to save some stack. Thanks to Andrew Morton for commenting different versions. Signed-off-by: Fabian Frederick <fabf@skynet.be> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03mm/readahead.c: fix readahead failure for memoryless NUMA nodes and limit ↵Raghavendra K T1-2/+2
readahead pages Currently max_sane_readahead() returns zero on the cpu whose NUMA node has no local memory which leads to readahead failure. Fix this readahead failure by returning minimum of (requested pages, 512). Users running applications on a memory-less cpu which needs readahead such as streaming application see considerable boost in the performance. Result: fadvise experiment with FADV_WILLNEED on a PPC machine having memoryless CPU with 1GB testfile (12 iterations) yielded around 46.66% improvement. fadvise experiment with FADV_WILLNEED on a x240 machine with 1GB testfile 32GB* 4G RAM numa machine (12 iterations) showed no impact on the normal NUMA cases w/ patch. Kernel Avg Stddev base 7.4975 3.92% patched 7.4174 3.26% [Andrew: making return value PAGE_SIZE independent] Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03mm + fs: prepare for non-page entries in page cache radix treesJohannes Weiner1-1/+1
shmem mappings already contain exceptional entries where swap slot information is remembered. To be able to store eviction information for regular page cache, prepare every site dealing with the radix trees directly to handle entries other than pages. The common lookup functions will filter out non-page entries and return NULL for page cache holes, just as before. But provide a raw version of the API which returns non-page entries as well, and switch shmem over to use it. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-03mm: filemap: move radix tree hole searching hereJohannes Weiner1-2/+2
The radix tree hole searching code is only used for page cache, for example the readahead code trying to get a a picture of the area surrounding a fault. It sufficed to rely on the radix tree definition of holes, which is "empty tree slot". But this is about to change, though, as shadow page descriptors will be stored in the page cache after the actual pages get evicted from memory. Move the functions over to mm/filemap.c and make them native page cache operations, where they can later be adapted to handle the new definition of "page cache hole". Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-01-29mm/readahead.c: fix do_readahead() for no readpage(s)Mark Rutland1-10/+5
Commit 63d0f0a3c7e1 ("mm/readahead.c:do_readhead(): don't check for ->readpage") unintentionally made do_readahead return 0 for all valid files regardless of whether readahead was supported, rather than the expected -EINVAL. This gets forwarded on to userspace, and results in sys_readahead appearing to succeed in cases that don't make sense (e.g. when called on pipes or sockets). This issue is detected by the LTP readahead01 testcase. As the exact return value of force_page_cache_readahead is currently never used, we can simplify it to return only 0 or -EINVAL (when readpage or readpages is missing). With that in place we can simply forward on the return value of force_page_cache_readahead in do_readahead. This patch performs said change, restoring the expected semantics. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13readahead: fix sequential read cache miss detectionDamien Ramonda1-1/+5
The kernel's readahead algorithm sometimes interprets random read accesses as sequential and triggers unnecessary data prefecthing from storage device (impacting random read average latency). In order to identify sequential cache read misses, the readahead algorithm intends to check whether offset - previous offset == 1 (trivial sequential reads) or offset - previous offset == 0 (sequential reads not aligned on page boundary): if (offset - (ra->prev_pos >> PAGE_CACHE_SHIFT) <= 1UL) The current offset is stored in the "offset" variable of type "pgoff_t" (unsigned long), while previous offset is stored in "ra->prev_pos" of type "loff_t" (long long). Therefore, operands of the if statement are implicitly converted to type long long. Consequently, when previous offset > current offset (which happens on random pattern), the if condition is true and access is wrongly interpeted as sequential. An unnecessary data prefetching is triggered, impacting the average random read latency. Storing the previous offset value in a "pgoff_t" variable (unsigned long) fixes the sequential read detection logic. Signed-off-by: Damien Ramonda <damien.ramonda@intel.com> Reviewed-by: Fengguang Wu <fengguang.wu@intel.com> Acked-by: Pierre Tardy <pierre.tardy@intel.com> Acked-by: David Cohen <david.a.cohen@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13mm/readahead.c:do_readhead(): don't check for ->readpageAndrew Morton1-1/+1
The callee force_page_cache_readahead() already does this and unlike do_readahead(), force_page_cache_readahead() remembers to check for ->readpages() as well. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11readahead: make context readahead more conservativeFengguang Wu1-4/+4
This helps performance on moderately dense random reads on SSD. Transaction-Per-Second numbers provided by Taobao: QPS case ------------------------------------------------------- 7536 disable context readahead totally w/ patch: 7129 slower size rampup and start RA on the 3rd read 6717 slower size rampup w/o patch: 5581 unmodified context readahead Before, readahead will be started whenever reading page N+1 when it happen to read N recently. After patch, we'll only start readahead when *three* random reads happen to access pages N, N+1, N+2. The probability of this happening is extremely low for pure random reads, unless they are very dense, which actually deserves some readahead. Also start with a smaller readahead window. The impact to interleaved sequential reads should be small, because for a long run stream, the the small readahead window rampup phase is negletable. The context readahead actually benefits clustered random reads on HDD whose seek cost is pretty high. However as SSD is increasingly used for random read workloads it's better for the context readahead to concentrate on interleaved sequential reads. Another SSD rand read test from Miao # file size: 2GB # read IO amount: 625MB sysbench --test=fileio \ --max-requests=10000 \ --num-threads=1 \ --file-num=1 \ --file-block-size=64K \ --file-test-mode=rndrd \ --file-fsync-freq=0 \ --file-fsync-end=off run shows the performance of btrfs grows up from 69MB/s to 121MB/s, ext4 from 104MB/s to 121MB/s. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Tested-by: Tao Ma <tm@tao.ma> Tested-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-21mm: change invalidatepage prototype to accept lengthLukas Czerner1-1/+1
Currently there is no way to truncate partial page where the end truncate point is not at the end of the page. This is because it was not needed and the functionality was enough for file system truncate operation to work properly. However more file systems now support punch hole feature and it can benefit from mm supporting truncating page just up to the certain point. Specifically, with this functionality truncate_inode_pages_range() can be changed so it supports truncating partial page at the end of the range (currently it will BUG_ON() if 'end' is not at the end of the page). This commit changes the invalidatepage() address space operation prototype to accept range to be invalidated and update all the instances for it. We also change the block_invalidatepage() in the same way and actually make a use of the new length argument implementing range invalidation. Actual file system implementations will follow except the file systems where the changes are really simple and should not change the behaviour in any way .Implementation for truncate_page_range() which will be able to accept page unaligned ranges will follow as well. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com>
2013-03-03teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long longAl Viro1-8/+1
... and convert a bunch of SYSCALL_DEFINE ones to SYSCALL_DEFINE<n>, killing the boilerplate crap around them. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26switch simple cases of fget_light to fdgetAl Viro1-8/+7
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-09-26switch readahead(2) to fget_light()Al Viro1-2/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-29mm: move readahead syscall to mm/readahead.cCong Wang1-0/+40
It is better to define readahead(2) in mm/readahead.c than in mm/filemap.c. Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-10-31mm: Map most files to use export.h instead of module.hPaul Gortmaker1-1/+1
The files changed within are only using the EXPORT_SYMBOL macro variants. They are not using core modular infrastructure and hence don't need module.h but only the export.h header. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-05-25readahead: readahead page allocations are OK to failWu Fengguang1-1/+1
Pass __GFP_NORETRY|__GFP_NOWARN for readahead page allocations. readahead page allocations are completely optional. They are OK to fail and in particular shall not trigger OOM on themselves. Reported-by: Dave Young <hidave.darkstar@gmail.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-10read-ahead: use pluggingJens Axboe1-0/+6
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-10block: remove per-queue pluggingJens Axboe1-12/+0
Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-05-25readahead.c: fix commentHuang Shijie1-1/+1
Fix a wrong comment over page_cache_async_readahead(). Signed-off-by: Huang Shijie <shijie8@gmail.com> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-07readahead: fix NULL filp dereferenceWu Fengguang1-1/+1
btrfs relocate_file_extent_cluster() calls us with NULL filp: [ 4005.426805] BUG: unable to handle kernel NULL pointer dereference at 00000021 [ 4005.426818] IP: [<c109a130>] page_cache_sync_readahead+0x18/0x3e Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Yan Zheng <yanzheng@21cn.com> Reported-by: Kirill A. Shutemov <kirill@shutemov.name> Tested-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo1-0/+1
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-06readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOMWu Fengguang1-0/+6
This fixes inefficient page-by-page reads on POSIX_FADV_RANDOM. POSIX_FADV_RANDOM used to set ra_pages=0, which leads to poor performance: a 16K read will be carried out in 4 _sync_ 1-page reads. In other places, ra_pages==0 means - it's ramfs/tmpfs/hugetlbfs/sysfs/configfs - some IO error happened where multi-page read IO won't help or should be avoided. POSIX_FADV_RANDOM actually want a different semantics: to disable the *heuristic* readahead algorithm, and to use a dumb one which faithfully submit read IO for whatever application requests. So introduce a flag FMODE_RANDOM for POSIX_FADV_RANDOM. Note that the random hint is not likely to help random reads performance noticeably. And it may be too permissive on huge request size (its IO size is not limited by read_ahead_kb). In Quentin's report (http://lkml.org/lkml/2009/12/24/145), the overall (NFS read) performance of the application increased by 313%! Tested-by: Quentin Barnes <qbarnes+nfs@yahoo-inc.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Andi Kleen <andi@firstfloor.org> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: <stable@kernel.org> [2.6.33.x] Cc: <qbarnes+nfs@yahoo-inc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-17readahead: add blk_run_backing_devHisashi Hifumi1-0/+12
I added blk_run_backing_dev on page_cache_async_readahead so readahead I/O is unpluged to improve throughput on especially RAID environment. The normal case is, if page N become uptodate at time T(N), then T(N) <= T(N+1) holds. With RAID (and NFS to some degree), there is no strict ordering, the data arrival time depends on runtime status of individual disks, which breaks that formula. So in do_generic_file_read(), just after submitting the async readahead IO request, the current page may well be uptodate, so the page won't be locked, and the block device won't be implicitly unplugged: if (PageReadahead(page)) page_cache_async_readahead() if (!PageUptodate(page)) goto page_not_up_to_date; //... page_not_up_to_date: lock_page_killable(page); Therefore explicit unplugging can help. Following is the test result with dd. #dd if=testdir/testfile of=/dev/null bs=16384 -2.6.30-rc6 1048576+0 records in 1048576+0 records out 17179869184 bytes (17 GB) copied, 224.182 seconds, 76.6 MB/s -2.6.30-rc6-patched 1048576+0 records in 1048576+0 records out 17179869184 bytes (17 GB) copied, 206.465 seconds, 83.2 MB/s (7Disks RAID-0 Array) -2.6.30-rc6 1054976+0 records in 1054976+0 records out 17284726784 bytes (17 GB) copied, 212.233 seconds, 81.4 MB/s -2.6.30-rc6-patched 1054976+0 records out 17284726784 bytes (17 GB) copied, 198.878 seconds, 86.9 MB/s (7Disks RAID-5 Array) The patch was found to improve performance with the SCST scsi target driver. See http://sourceforge.net/mailarchive/forum.php?thread_name=a0272b440906030714g67eabc5k8f847fb1e538cc62%40mail.gmail.com&forum_name=scst-devel [akpm@linux-foundation.org: unbust comment layout] [akpm@linux-foundation.org: "fix" CONFIG_BLOCK=n] Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Tested-by: Ronald <intercommit@gmail.com> Cc: Bart Van Assche <bart.vanassche@gmail.com> Cc: Vladislav Bolkhovitin <vst@vlnb.net> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: introduce context readahead algorithmWu Fengguang1-0/+60
Introduce page cache context based readahead algorithm. This is to better support concurrent read streams in general. RATIONALE --------- The current readahead algorithm detects interleaved reads in a _passive_ way. Given a sequence of interleaved streams 1,1001,2,1002,3,4,1003,5,1004,1005,6,... By checking for (offset == prev_offset + 1), it will discover the sequentialness between 3,4 and between 1004,1005, and start doing sequential readahead for the individual streams since page 4 and page 1005. The context readahead algorithm guarantees to discover the sequentialness no matter how the streams are interleaved. For the above example, it will start sequential readahead since page 2 and 1002. The trick is to poke for page @offset-1 in the page cache when it has no other clues on the sequentialness of request @offset: if the current requenst belongs to a sequential stream, that stream must have accessed page @offset-1 recently, and the page will still be cached now. So if page @offset-1 is there, we can take request @offset as a sequential access. BENEFICIARIES ------------- - strictly interleaved reads i.e. 1,1001,2,1002,3,1003,... the current readahead will take them as silly random reads; the context readahead will take them as two sequential streams. - cooperative IO processes i.e. NFS and SCST They create a thread pool, farming off (sequential) IO requests to different threads which will be performing interleaved IO. It was not easy(or possible) to reliably tell from file->f_ra all those cooperative processes working on the same sequential stream, since they will have different file->f_ra instances. And NFSD's file->f_ra is particularly unusable, since their file objects are dynamically created for each request. The nfsd does have code trying to restore the f_ra bits, but not satisfactory. The new scheme is to detect the sequential pattern via looking up the page cache, which provides one single and consistent view of the pages recently accessed. That makes sequential detection for cooperative processes possible. USER REPORT ----------- Vladislav recommends the addition of context readahead as a result of his SCST benchmarks. It leads to 6%~40% performance gains in various cases and achieves equal performance in others. http://lkml.org/lkml/2009/3/19/239 OVERHEADS --------- In theory, it introduces one extra page cache lookup per random read. However the below benchmark shows context readahead to be slightly faster, wondering.. Randomly reading 200MB amount of data on a sparse file, repeat 20 times for each block size. The average throughputs are: original ra context ra gain 4K random reads: 65.561MB/s 65.648MB/s +0.1% 16K random reads: 124.767MB/s 124.951MB/s +0.1% 64K random reads: 162.123MB/s 162.278MB/s +0.1% Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Tested-by: Vladislav Bolkhovitin <vst@vlnb.net> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: move the random read case to bottomWu Fengguang1-21/+25
Split all readahead cases, and move the random one to bottom. No behavior changes. This is to prepare for the introduction of context readahead, and make it easy for inserting accounting/tracing points for each case. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Vladislav Bolkhovitin <vst@vlnb.net> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: record mmap read-around states in file_ra_stateWu Fengguang1-21/+2
Mmap read-around now shares the same code style and data structure with readahead code. This also removes do_page_cache_readahead(). Its last user, mmap read-around, has been changed to call ra_submit(). The no-readahead-if-congested logic is dumped by the way. Users will be pretty sensitive about the slow loading of executables. So it's unfavorable to disabled mmap read-around on a congested queue. [akpm@linux-foundation.org: coding-style fixes] Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: remove sync/async readahead call dependencyWu Fengguang1-0/+10
The readahead call scheme is error-prone in that it expects the call sites to check for async readahead after doing a sync one. I.e. if (!page) page_cache_sync_readahead(); page = find_get_page(); if (page && PageReadahead(page)) page_cache_async_readahead(); This is because PG_readahead could be set by a sync readahead for the _current_ newly faulted in page, and the readahead code simply expects one more callback on the same page to start the async readahead. If the caller fails to do so, it will miss the PG_readahead bits and never able to start an async readahead. Eliminate this insane constraint by piggy-backing the async part into the current readahead window. Now if an async readahead should be started immediately after a sync one, the readahead logic itself will do it. So the following code becomes valid: (the 'else' in particular) if (!page) page_cache_sync_readahead(); else if (PageReadahead(page)) page_cache_async_readahead(); Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: increase interleaved readahead sizeWu Fengguang1-0/+1
Make sure interleaved readahead size is larger than request size. This also makes the readahead window grow up more quickly. Reported-by: Xu Chenfeng <xcf@ustc.edu.cn> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: remove one unnecessary radix tree lookupWu Fengguang1-1/+1
(hit_readahead_marker != 0) means the page at @offset is present, so we can search for non-present page starting from @offset+1. Reported-by: Xu Chenfeng <xcf@ustc.edu.cn> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: apply max_sane_readahead() limit in ondemand_readahead()Wu Fengguang1-1/+1
Just in case someone aggressively sets a huge readahead size. Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16readahead: move max_sane_readahead() calls into force_page_cache_readahead()Wu Fengguang1-0/+1
Impact: code simplification. Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-03FS-Cache: Recruit a page flags for cache managementDavid Howells1-4/+5
Recruit a page flag to aid in cache management. The following extra flag is defined: (1) PG_fscache (PG_private_2) The marked page is backed by a local cache and is pinning resources in the cache driver. If PG_fscache is set, then things that checked for PG_private will now also check for that. This includes things like truncation and page invalidation. The function page_has_private() had been added to make the checks for both PG_private and PG_private_2 at the same time. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03FS-Cache: Release page->private after failed readaheadDavid Howells1-2/+37
The attached patch causes read_cache_pages() to release page-private data on a page for which add_to_page_cache() fails. If the filler function fails, then the problematic page is left attached to the pagecache (with appropriate flags set, one presumes) and the remaining to-be-attached pages are invalidated and discarded. This permits pages with caching references associated with them to be cleaned up. The invalidatepage() address space op is called (indirectly) to do the honours. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-03-26Move the default_backing_dev_info out of readahead.c and into backing-dev.cJens Axboe1-25/+0
It really makes no sense to have it in readahead.c, so move it where it belongs. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-20vmscan: split LRU lists into anon & file setsRik van Riel1-1/+1
Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16Remove Andrew Morton's old email accountsFrancois Cami1-1/+1
People can use the real name an an index into MAINTAINERS to find the current email address. Signed-off-by: Francois Cami <francois.cami@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26mm: readahead scan locklessNick Piggin1-3/+3
radix_tree_next_hole() is implemented as a series of radix_tree_lookup()s. So it can be called locklessly, under rcu_read_lock(). Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Hugh Dickins <hugh@veritas.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30mm: bdi: export BDI attributes in sysfsPeter Zijlstra1-1/+7
Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object. This allows us to see and set the various BDI specific variables. In particular this properly exposes the read-ahead window for all relevant users and /sys/block/<block>/queue/read_ahead_kb should be deprecated. With patient help from Kay Sievers and Greg KH [mszeredi@suse.cz] - split off NFS and FUSE changes into separate patches - document new sysfs attributes under Documentation/ABI - do bdi_class_init as a core_initcall, otherwise the "default" BDI won't be initialized - remove bdi_init_fmt macro, it's not used very much [akpm@linux-foundation.org: fix ia64 warning] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Greg KH <greg@kroah.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-19mm/readahead: fix kernel-doc notationRandy Dunlap1-2/+3
Fix kernel-doc notation in mm/readahead.c. Change ":" to ";" so that it doesn't get treated as a doc section heading. Move the comment block ending "*/" to a line by itself so that the text on that last line is not lost (dropped). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17mm: bdi init hooksPeter Zijlstra1-0/+6
provide BDI constructor/destructor hooks [akpm@linux-foundation.org: compile fix] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 16:18:04 +0000