- 02 Jun, 2020 40 commits
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Souptick Joarder authored
This patch is an attempt to update the documentation. - Add/ remove extra * based on type of function static/global. - Add description for functions and their input arguments. [akpm@linux-foundation.org: s@/*@/**@] Signed-off-by:
Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Reviewed-by:
Linus Torvalds <torvalds@linux-foundation.org>
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NeilBrown authored
After an NFS page has been written it is considered "unstable" until a COMMIT request succeeds. If the COMMIT fails, the page will be re-written. These "unstable" pages are currently accounted as "reclaimable", either in WB_RECLAIMABLE, or in NR_UNSTABLE_NFS which is included in a 'reclaimable' count. This might have made sense when sending the COMMIT required a separate action by the VFS/MM (e.g. releasepage() used to send a COMMIT). However now that all writes generated by ->writepages() will automatically be followed by a COMMIT (since commit 919e3bd9 ("NFS: Ensure we commit after writeback is complete")) it makes more sense to treat them as writeback pages. So this patch removes NR_UNSTABLE_NFS and accounts unstable pages in NR_WRITEBACK and WB_WRITEBACK. A particular effect of this change is that when wb_check_background_flush() calls wb_over_bg_threshold(), the latter will report 'true' a lot less often as the 'unstable' pages are no longer considered 'dirty' (as there is nothing that writeback can do about them anyway). Currently wb_check_background_flush() will trigger writeback to NFS even when there are relatively few dirty pages (if there are lots of unstable pages), this can result in small writes going to the server (10s of Kilobytes rather than a Megabyte) which hurts throughput. With this patch, there are fewer writes which are each larger on average. Where the NR_UNSTABLE_NFS count was included in statistics virtual-files, the entry is retained, but the value is hard-coded as zero. static trace points and warning printks which mentioned this counter no longer report it. [akpm@linux-foundation.org: re-layout comment] [akpm@linux-foundation.org: fix printk warning] Signed-off-by:
NeilBrown <neilb@suse.de> Signed-off-by:
Jan Kara <jack@suse.cz> Reviewed-by:
Christoph Hellwig <hch@lst.de> Acked-by:
Trond Myklebust <trond.myklebust@hammerspace.com> Acked-by: Michal Hocko <mhocko@suse.com> [mm] Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Link: http://lkml.kernel.org/r/87d06j7gqa.fsf@notabene.neil.brown.nameSigned-off-by:
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NeilBrown authored
PF_LESS_THROTTLE exists for loop-back nfsd (and a similar need in the loop block driver and callers of prctl(PR_SET_IO_FLUSHER)), where a daemon needs to write to one bdi (the final bdi) in order to free up writes queued to another bdi (the client bdi). The daemon sets PF_LESS_THROTTLE and gets a larger allowance of dirty pages, so that it can still dirty pages after other processses have been throttled. The purpose of this is to avoid deadlock that happen when the PF_LESS_THROTTLE process must write for any dirty pages to be freed, but it is being thottled and cannot write. This approach was designed when all threads were blocked equally, independently on which device they were writing to, or how fast it was. Since that time the writeback algorithm has changed substantially with different threads getting different allowances based on non-trivial heuristics. This means the simple "add 25%" heuristic is no longer reliable. The important issue is not that the daemon needs a *larger* dirty page allowance, but that it needs a *private* dirty page allowance, so that dirty pages for the "client" bdi that it is helping to clear (the bdi for an NFS filesystem or loop block device etc) do not affect the throttling of the daemon writing to the "final" bdi. This patch changes the heuristic so that the task is not throttled when the bdi it is writing to has a dirty page count below below (or equal to) the free-run threshold for that bdi. This ensures it will always be able to have some pages in flight, and so will not deadlock. In a steady-state, it is expected that PF_LOCAL_THROTTLE tasks might still be throttled by global threshold, but that is acceptable as it is only the deadlock state that is interesting for this flag. This approach of "only throttle when target bdi is busy" is consistent with the other use of PF_LESS_THROTTLE in current_may_throttle(), were it causes attention to be focussed only on the target bdi. So this patch - renames PF_LESS_THROTTLE to PF_LOCAL_THROTTLE, - removes the 25% bonus that that flag gives, and - If PF_LOCAL_THROTTLE is set, don't delay at all unless the global and the local free-run thresholds are exceeded. Note that previously realtime threads were treated the same as PF_LESS_THROTTLE threads. This patch does *not* change the behvaiour for real-time threads, so it is now different from the behaviour of nfsd and loop tasks. I don't know what is wanted for realtime. [akpm@linux-foundation.org: coding style fixes] Signed-off-by:
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Chao Yu authored
Commit 64081362 ("mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock") left unused variable, remove it. Signed-off-by:
Chao Yu <yuchao0@huawei.com> Signed-off-by:
David Hildenbrand <david@redhat.com> Link: http://lkml.kernel.org/r/20200528033740.17269-1-yuchao0@huawei.comSigned-off-by:
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Matthew Wilcox (Oracle) authored
We no longer return 0 here and the comment doesn't tell us anything that we don't already know (SIGBUS is a pretty good indicator that things didn't work out). Signed-off-by:
Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by:
William Kucharski <william.kucharski@oracle.com> Link: http://lkml.kernel.org/r/20200529123243.20640-1-willy@infradead.orgSigned-off-by:
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Guoqing Jiang authored
Change it to inline function to make callers use the proper argument. And no need for it to be macro per Andrew's comment [1]. [1] https://lore.kernel.org/lkml/20200518221235.1fa32c38e5766113f78e3f0d@linux-foundation.org/Signed-off-by:
Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by:
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Guoqing Jiang authored
We can cleanup code a little by call detach_page_private here. [akpm@linux-foundation.org: use attach_page_private(), per Dave] http://lkml.kernel.org/r/20200521225220.GV2005@dread.disaster.area [akpm@linux-foundation.org: clear PagePrivate] Signed-off-by:
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Guoqing Jiang authored
All the callers have replaced attach_page_buffers with the new function attach_page_private, so remove it. Signed-off-by:
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Guoqing Jiang authored
Since the new pair function is introduced, we can call them to clean the code in orangefs. Signed-off-by:
Mike Marshall <hubcap@omnibond.com> Reviewed-by:
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Guoqing Jiang authored
Call the new function since attach_page_buffers will be removed. Signed-off-by:
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Guoqing Jiang authored
Since the new pair function is introduced, we can call them to clean the code in iomap. Signed-off-by:
Darrick J. Wong <darrick.wong@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Link: http://lkml.kernel.org/r/20200517214718.468-7-guoqing.jiang@cloud.ionos.comSigned-off-by:
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Guoqing Jiang authored
Since the new pair function is introduced, we can call them to clean the code in f2fs.h. Signed-off-by:
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Guoqing Jiang authored
Since the new pair function is introduced, we can call them to clean the code in buffer.c. Signed-off-by:
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Guoqing Jiang authored
Since the new pair function is introduced, we can call them to clean the code in btrfs. Signed-off-by:
David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Link: http://lkml.kernel.org/r/20200517214718.468-4-guoqing.jiang@cloud.ionos.comSigned-off-by:
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Guoqing Jiang authored
After introduction attach/detach_page_private in pagemap.h, we can remove the duplicated code and call the new functions. Signed-off-by:
Song Liu <song@kernel.org> Link: http://lkml.kernel.org/r/20200517214718.468-3-guoqing.jiang@cloud.ionos.comSigned-off-by:
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Guoqing Jiang authored
Patch series "Introduce attach/detach_page_private to cleanup code". This patch (of 10): The logic in attach_page_buffers and __clear_page_buffers are quite paired, but 1. they are located in different files. 2. attach_page_buffers is implemented in buffer_head.h, so it could be used by other files. But __clear_page_buffers is static function in buffer.c and other potential users can't call the function, md-bitmap even copied the function. So, introduce the new attach/detach_page_private to replace them. With the new pair of function, we will remove the usage of attach_page_buffers and __clear_page_buffers in next patches. Thanks for suggestions about the function name from Alexander Viro, Andreas Grünbacher, Christoph Hellwig and Matthew Wilcox. Suggested-by:
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Matthew Wilcox (Oracle) authored
Use the new readahead operation in iomap. Convert XFS and ZoneFS to use it. Signed-off-by:
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Matthew Wilcox (Oracle) authored
Implement the new readahead operation in fuse by using __readahead_batch() to fill the array of pages in fuse_args_pages directly. This lets us inline fuse_readpages_fill() into fuse_readahead(). [willy@infradead.org: build fix] Link: http://lkml.kernel.org/r/20200415025938.GB5820@bombadil.infradead.orgSigned-off-by:
Dave Chinner <dchinner@redhat.com> Reviewed-by:
Miklos Szeredi <mszeredi@redhat.com> Cc: Chao Yu <yuchao0@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Gao Xiang <gaoxiang25@huawei.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: http://lkml.kernel.org/r/20200414150233.24495-25-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
This function now only uses the mapping argument to look up the inode, and both callers already have the inode, so just pass the inode instead of the mapping. Signed-off-by:
Eric Biggers <ebiggers@google.com> Reviewed-by:
Jaegeuk Kim <jaegeuk@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Gao Xiang <gaoxiang25@huawei.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Link: http://lkml.kernel.org/r/20200414150233.24495-24-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Use the new readahead operation in f2fs Signed-off-by:
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Matthew Wilcox (Oracle) authored
This function now only uses the mapping argument to look up the inode, and both callers already have the inode, so just pass the inode instead of the mapping. Signed-off-by:
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Matthew Wilcox (Oracle) authored
Use the new readahead operation in ext4 Signed-off-by:
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Matthew Wilcox (Oracle) authored
Use the new readahead operation in erofs. Signed-off-by:
Gao Xiang <gaoxiang25@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Link: http://lkml.kernel.org/r/20200414150233.24495-20-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
Use the new readahead operation in erofs Signed-off-by:
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Matthew Wilcox (Oracle) authored
Implement the new readahead method in btrfs using the new readahead_page_batch() function. Signed-off-by:
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Matthew Wilcox (Oracle) authored
Implement the new readahead aop and convert all callers (block_dev, exfat, ext2, fat, gfs2, hpfs, isofs, jfs, nilfs2, ocfs2, omfs, qnx6, reiserfs & udf). The callers are all trivial except for GFS2 & OCFS2. Signed-off-by:
John Hubbard <jhubbard@nvidia.com> Reviewed-by:
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Matthew Wilcox (Oracle) authored
Ensure that memory allocations in the readahead path do not attempt to reclaim file-backed pages, which could lead to a deadlock. It is possible, though unlikely this is the root cause of a problem observed by Cong Wang. Reported-by:
Cong Wang <xiyou.wangcong@gmail.com> Suggested-by:
Michal Hocko <mhocko@suse.com> Signed-off-by:
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Matthew Wilcox (Oracle) authored
If the page is already in cache, we don't set PageReadahead on it. Signed-off-by:
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Matthew Wilcox (Oracle) authored
ext4 and f2fs have duplicated the guts of the readahead code so they can read past i_size. Instead, separate out the guts of the readahead code so they can call it directly. Signed-off-by:
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Matthew Wilcox (Oracle) authored
By reducing nr_to_read, we can eliminate this check from inside the loop. Signed-off-by:
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Matthew Wilcox (Oracle) authored
This replaces ->readpages with a saner interface: - Return void instead of an ignored error code. - Page cache is already populated with locked pages when ->readahead is called. - New arguments can be passed to the implementation without changing all the filesystems that use a common helper function like mpage_readahead(). Signed-off-by:
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Matthew Wilcox (Oracle) authored
When populating the page cache for readahead, mappings that use ->readpages must populate the page cache themselves as the pages are passed on a linked list which would normally be used for the page cache's LRU. For mappings that use ->readpage or the upcoming ->readahead method, we can put the pages into the page cache as soon as they're allocated, which solves a race between readahead and direct IO. It also lets us remove the gfp argument from read_pages(). Use the new readahead_page() API to implement the repeated calls to ->readpage(), just like most filesystems will. Signed-off-by:
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Matthew Wilcox (Oracle) authored
Replace the page_offset variable with 'index + i'. Signed-off-by:
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Matthew Wilcox (Oracle) authored
Change the type of page_idx to unsigned long, and rename it -- it's just a loop counter, not a page index. Suggested-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Chao Yu <yuchao0@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Gao Xiang <gaoxiang25@huawei.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Link: http://lkml.kernel.org/r/20200414150233.24495-9-willy@infradead.orgSigned-off-by:
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Matthew Wilcox (Oracle) authored
The word 'offset' is used ambiguously to mean 'byte offset within a page', 'byte offset from the start of the file' and 'page offset from the start of the file'. Use 'index' to mean 'page offset from the start of the file' throughout the readahead code. [ We should probably rename the 'pgoff_t' type to 'pgidx_t' too - Linus ] Signed-off-by:
Zi Yan <ziy@nvidia.com> Reviewed-by:
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Matthew Wilcox (Oracle) authored
In this patch, only between __do_page_cache_readahead() and read_pages(), but it will be extended in upcoming patches. The read_pages() function becomes aops centric, as this makes the most sense by the end of the patchset. Signed-off-by:
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Matthew Wilcox (Oracle) authored
Filesystems which implement the upcoming ->readahead method will get their pages by calling readahead_page() or readahead_page_batch(). These functions support large pages, even though none of the filesystems to be converted do yet. Signed-off-by:
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Matthew Wilcox (Oracle) authored
Simplify the callers by moving the check for nr_pages and the BUG_ON into read_pages(). Signed-off-by:
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Matthew Wilcox (Oracle) authored
We used to assign the return value to a variable, which we then ignored. Remove the pretence of caring. Signed-off-by:
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Matthew Wilcox (Oracle) authored
ondemand_readahead has two callers, neither of which use the return value. That means that both ra_submit and __do_page_cache_readahead() can return void, and we don't need to worry that a present page in the readahead window causes us to return a smaller nr_pages than we ought to have. Similarly, no caller uses the return value from force_page_cache_readahead(). Signed-off-by:
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