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linux/drivers/md/bcache/writeback.h

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
/* SPDX-License-Identifier: GPL-2.0 */
bcache: Track dirty data by stripe To make background writeback aware of raid5/6 stripes, we first need to track the amount of dirty data within each stripe - we do this by breaking up the existing sectors_dirty into per stripe atomic_ts Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:21:07 +00:00
#ifndef _BCACHE_WRITEBACK_H
#define _BCACHE_WRITEBACK_H
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
#define CUTOFF_WRITEBACK 40
#define CUTOFF_WRITEBACK_SYNC 70
bcache: fix wrong return value in bch_debug_init() in bch_debug_init(), ret is always 0, and the return value is useless, change it to return 0 if be success after calling debugfs_create_dir(), else return a non-zero value. Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn> Reviewed-by: Michael Lyle <mlyle@lyle.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-08 20:21:22 +00:00
#define MAX_WRITEBACKS_IN_PASS 5
#define MAX_WRITESIZE_IN_PASS 5000 /* *512b */
bcache: fix writeback target calc on large devices Bcache needs to scale the dirty data in the cache over the multiple backing disks in order to calculate writeback rates for each. The previous code did this by multiplying the target number of dirty sectors by the backing device size, and expected it to fit into a uint64_t; this blows up on relatively small backing devices. The new approach figures out the bdev's share in 16384ths of the overall cached data. This is chosen to cope well when bdevs drastically vary in size and to ensure that bcache can cross the petabyte boundary for each backing device. This has been improved based on Tang Junhui's feedback to ensure that every device gets a share of dirty data, no matter how small it is compared to the total backing pool. The existing mechanism is very limited; this is purely a bug fix to remove limits on volume size. However, there still needs to be change to make this "fair" over many volumes where some are idle. Reported-by: Jack Douglas <jack@douglastechnology.co.uk> Signed-off-by: Michael Lyle <mlyle@lyle.org> Reviewed-by: Tang Junhui <tang.junhui@zte.com.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-08 20:21:30 +00:00
/*
* 14 (16384ths) is chosen here as something that each backing device
* should be a reasonable fraction of the share, and not to blow up
* until individual backing devices are a petabyte.
*/
#define WRITEBACK_SHARE_SHIFT 14
bcache: Track dirty data by stripe To make background writeback aware of raid5/6 stripes, we first need to track the amount of dirty data within each stripe - we do this by breaking up the existing sectors_dirty into per stripe atomic_ts Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:21:07 +00:00
static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
{
uint64_t i, ret = 0;
for (i = 0; i < d->nr_stripes; i++)
ret += atomic_read(d->stripe_sectors_dirty + i);
return ret;
}
bcache: correct cache_dirty_target in __update_writeback_rate() __update_write_rate() uses a Proportion-Differentiation Controller algorithm to control writeback rate. A dirty target number is used in this PD controller to control writeback rate. A larger target number will make the writeback rate smaller, on the versus, a smaller target number will make the writeback rate larger. bcache uses the following steps to calculate the target number, 1) cache_sectors = all-buckets-of-cache-set * buckets-size 2) cache_dirty_target = cache_sectors * cached-device-writeback_percent 3) target = cache_dirty_target * (sectors-of-cached-device/sectors-of-all-cached-devices-of-this-cache-set) The calculation at step 1) for cache_sectors is incorrect, which does not consider dirty blocks occupied by flash only volume. A flash only volume can be took as a bcache device without cached device. All data sectors allocated for it are persistent on cache device and marked dirty, they are not touched by bcache writeback and garbage collection code. So data blocks of flash only volume should be ignore when calculating cache_sectors of cache set. Current code does not subtract dirty sectors of flash only volume, which results a larger target number from the above 3 steps. And in sequence the cache device's writeback rate is smaller then a correct value, writeback speed is slower on all cached devices. This patch fixes the incorrect slower writeback rate by subtracting dirty sectors of flash only volumes in __update_writeback_rate(). (Commit log composed by Coly Li to pass checkpatch.pl checking) Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn> Reviewed-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-06 06:25:56 +00:00
static inline uint64_t bcache_flash_devs_sectors_dirty(struct cache_set *c)
{
uint64_t i, ret = 0;
mutex_lock(&bch_register_lock);
bcache: reduce cache_set devices iteration by devices_max_used Member devices of struct cache_set is used to reference all attached bcache devices to this cache set. If it is treated as array of pointers, size of devices[] is indicated by member nr_uuids of struct cache_set. nr_uuids is calculated in drivers/md/super.c:bch_cache_set_alloc(), bucket_bytes(c) / sizeof(struct uuid_entry) Bucket size is determined by user space tool "make-bcache", by default it is 1024 sectors (defined in bcache-tools/make-bcache.c:main()). So default nr_uuids value is 4096 from the above calculation. Every time when bcache code iterates bcache devices of a cache set, all the 4096 pointers are checked even only 1 bcache device is attached to the cache set, that's a wast of time and unncessary. This patch adds a member devices_max_used to struct cache_set. Its value is 1 + the maximum used index of devices[] in a cache set. When iterating all valid bcache devices of a cache set, use c->devices_max_used in for-loop may reduce a lot of useless checking. Personally, my motivation of this patch is not for performance, I use it in bcache debugging, which helps me to narrow down the scape to check valid bcached devices of a cache set. Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Michael Lyle <mlyle@lyle.org> Reviewed-by: Tang Junhui <tang.junhui@zte.com.cn> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-08 20:21:28 +00:00
for (i = 0; i < c->devices_max_used; i++) {
bcache: correct cache_dirty_target in __update_writeback_rate() __update_write_rate() uses a Proportion-Differentiation Controller algorithm to control writeback rate. A dirty target number is used in this PD controller to control writeback rate. A larger target number will make the writeback rate smaller, on the versus, a smaller target number will make the writeback rate larger. bcache uses the following steps to calculate the target number, 1) cache_sectors = all-buckets-of-cache-set * buckets-size 2) cache_dirty_target = cache_sectors * cached-device-writeback_percent 3) target = cache_dirty_target * (sectors-of-cached-device/sectors-of-all-cached-devices-of-this-cache-set) The calculation at step 1) for cache_sectors is incorrect, which does not consider dirty blocks occupied by flash only volume. A flash only volume can be took as a bcache device without cached device. All data sectors allocated for it are persistent on cache device and marked dirty, they are not touched by bcache writeback and garbage collection code. So data blocks of flash only volume should be ignore when calculating cache_sectors of cache set. Current code does not subtract dirty sectors of flash only volume, which results a larger target number from the above 3 steps. And in sequence the cache device's writeback rate is smaller then a correct value, writeback speed is slower on all cached devices. This patch fixes the incorrect slower writeback rate by subtracting dirty sectors of flash only volumes in __update_writeback_rate(). (Commit log composed by Coly Li to pass checkpatch.pl checking) Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn> Reviewed-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-06 06:25:56 +00:00
struct bcache_device *d = c->devices[i];
if (!d || !UUID_FLASH_ONLY(&c->uuids[i]))
continue;
ret += bcache_dev_sectors_dirty(d);
}
mutex_unlock(&bch_register_lock);
return ret;
}
bcache: Better full stripe scanning The old scanning-by-stripe code burned too much CPU, this should be better. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-10-31 22:43:22 +00:00
static inline unsigned offset_to_stripe(struct bcache_device *d,
uint64_t offset)
{
do_div(offset, d->stripe_size);
return offset;
}
static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
uint64_t offset,
unsigned nr_sectors)
{
bcache: Better full stripe scanning The old scanning-by-stripe code burned too much CPU, this should be better. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-10-31 22:43:22 +00:00
unsigned stripe = offset_to_stripe(&dc->disk, offset);
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
while (1) {
bcache: Better full stripe scanning The old scanning-by-stripe code burned too much CPU, this should be better. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-10-31 22:43:22 +00:00
if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
return true;
bcache: Better full stripe scanning The old scanning-by-stripe code burned too much CPU, this should be better. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-10-31 22:43:22 +00:00
if (nr_sectors <= dc->disk.stripe_size)
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
return false;
bcache: Better full stripe scanning The old scanning-by-stripe code burned too much CPU, this should be better. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-10-31 22:43:22 +00:00
nr_sectors -= dc->disk.stripe_size;
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
stripe++;
}
}
static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
unsigned cache_mode, bool would_skip)
{
unsigned in_use = dc->disk.c->gc_stats.in_use;
if (cache_mode != CACHE_MODE_WRITEBACK ||
bcache: Fix sysfs splat on shutdown with flash only devs Whoops. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-08-22 00:49:09 +00:00
test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
in_use > CUTOFF_WRITEBACK_SYNC)
return false;
if (dc->partial_stripes_expensive &&
block: Abstract out bvec iterator Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Ed L. Cashin" <ecashin@coraid.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Lars Ellenberg <drbd-dev@lists.linbit.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Yehuda Sadeh <yehuda@inktank.com> Cc: Sage Weil <sage@inktank.com> Cc: Alex Elder <elder@inktank.com> Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Neil Brown <neilb@suse.de> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: dm-devel@redhat.com Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux390@de.ibm.com Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Benny Halevy <bhalevy@tonian.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Chris Mason <chris.mason@fusionio.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Joern Engel <joern@logfs.org> Cc: Prasad Joshi <prasadjoshi.linux@gmail.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Ben Myers <bpm@sgi.com> Cc: xfs@oss.sgi.com Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Guo Chao <yan@linux.vnet.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: "Roger Pau Monné" <roger.pau@citrix.com> Cc: Jan Beulich <jbeulich@suse.com> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Cc: Ian Campbell <Ian.Campbell@citrix.com> Cc: Sebastian Ott <sebott@linux.vnet.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchand@redhat.com> Cc: Joe Perches <joe@perches.com> Cc: Peng Tao <tao.peng@emc.com> Cc: Andy Adamson <andros@netapp.com> Cc: fanchaoting <fanchaoting@cn.fujitsu.com> Cc: Jie Liu <jeff.liu@oracle.com> Cc: Sunil Mushran <sunil.mushran@gmail.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Pankaj Kumar <pankaj.km@samsung.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Mel Gorman <mgorman@suse.de>6
2013-10-11 22:44:27 +00:00
bcache_dev_stripe_dirty(dc, bio->bi_iter.bi_sector,
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
bio_sectors(bio)))
return true;
if (would_skip)
return false;
bcache: update bio->bi_opf bypass/writeback REQ_ flag hints Flag for bypass if the IO is for read-ahead or background, unless the read-ahead request is for metadata (eg, from gfs2). Bypass if: bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) && !(bio->bi_opf & REQ_META)) Writeback if: op_is_sync(bio->bi_opf) || bio->bi_opf & (REQ_META|REQ_PRIO) Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net> Reviewed-by: Coly Li <colyli@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-13 23:35:33 +00:00
return (op_is_sync(bio->bi_opf) ||
bio->bi_opf & (REQ_META|REQ_PRIO) ||
in_use <= CUTOFF_WRITEBACK);
bcache: Write out full stripes Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:24:39 +00:00
}
bcache: Convert writeback to a kthread This simplifies the writeback flow control quite a bit - previously, it was conceptually two coroutines, refill_dirty() and read_dirty(). This makes the code quite a bit more straightforward. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-07-25 00:50:06 +00:00
static inline void bch_writeback_queue(struct cached_dev *dc)
{
bcache: prevent crash on changing writeback_running Added a safeguard in the shutdown case. At least while not being attached it is also possible to trigger a kernel bug by writing into writeback_running. This change adds the same check before trying to wake up the thread for that case. Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-11-30 02:44:49 +00:00
if (!IS_ERR_OR_NULL(dc->writeback_thread))
wake_up_process(dc->writeback_thread);
bcache: Convert writeback to a kthread This simplifies the writeback flow control quite a bit - previously, it was conceptually two coroutines, refill_dirty() and read_dirty(). This makes the code quite a bit more straightforward. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-07-25 00:50:06 +00:00
}
static inline void bch_writeback_add(struct cached_dev *dc)
{
if (!atomic_read(&dc->has_dirty) &&
!atomic_xchg(&dc->has_dirty, 1)) {
bcache: convert cached_dev.count from atomic_t to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable cached_dev.count is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Reviewed-by: Michael Lyle <mlyle@lyle.org> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-30 21:46:32 +00:00
refcount_inc(&dc->count);
bcache: Convert writeback to a kthread This simplifies the writeback flow control quite a bit - previously, it was conceptually two coroutines, refill_dirty() and read_dirty(). This makes the code quite a bit more straightforward. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2013-07-25 00:50:06 +00:00
if (BDEV_STATE(&dc->sb) != BDEV_STATE_DIRTY) {
SET_BDEV_STATE(&dc->sb, BDEV_STATE_DIRTY);
/* XXX: should do this synchronously */
bch_write_bdev_super(dc, NULL);
}
bch_writeback_queue(dc);
}
}
bcache: Track dirty data by stripe To make background writeback aware of raid5/6 stripes, we first need to track the amount of dirty data within each stripe - we do this by breaking up the existing sectors_dirty into per stripe atomic_ts Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:21:07 +00:00
void bcache_dev_sectors_dirty_add(struct cache_set *, unsigned, uint64_t, int);
bcache: initialize dirty stripes in flash_dev_run() bcache uses a Proportion-Differentiation Controller algorithm to control writeback rate to cached devices. In the PD controller algorithm, dirty stripes of thin flash device should not be counted in, because flash only volumes never write back dirty data. Currently dirty stripe counter for thin flash device is not initialized when the thin flash device starts. Which means the following calculation in PD controller will reference an undefined dirty stripes number, and all cached devices attached to the same cache set where the thin flash device lies on may have an inaccurate writeback rate. This patch calles bch_sectors_dirty_init() in flash_dev_run(), to correctly initialize dirty stripe counter when the thin flash device starts to run. This patch also does following parameter data type change, -void bch_sectors_dirty_init(struct cached_dev *dc); +void bch_sectors_dirty_init(struct bcache_device *); to call this function conveniently in flash_dev_run(). (Commit log is composed by Coly Li) Signed-off-by: Tang Junhui <tang.junhui@zte.com.cn> Reviewed-by: Coly Li <colyli@suse.de> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-06 17:28:53 +00:00
void bch_sectors_dirty_init(struct bcache_device *);
bcache: fix uninterruptible sleep in writeback thread There were two issues here: - writeback thread did not start until the device first became dirty - writeback thread used uninterruptible sleep once running Without this patch I see kernel warnings printed and a load average of 1.52 after booting my test VM. With this patch the warnings are gone and the load average is near 0.00 as expected. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
2014-05-01 20:48:57 +00:00
void bch_cached_dev_writeback_init(struct cached_dev *);
int bch_cached_dev_writeback_start(struct cached_dev *);
bcache: Track dirty data by stripe To make background writeback aware of raid5/6 stripes, we first need to track the amount of dirty data within each stripe - we do this by breaking up the existing sectors_dirty into per stripe atomic_ts Signed-off-by: Kent Overstreet <koverstreet@google.com>
2013-06-05 13:21:07 +00:00
#endif
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