kernel/linux.git/drivers/md/bcache/sysfs.c, branch linux-4.20.y

bcache: Populate writeback_rate_minimum attribute

2018-10-08T14:19:46+00:00

Forgot to include the maintainers with my first email. Somewhere between Michael Lyle's original "bcache: PI controller for writeback rate V2" patch dated 07 Sep 2017 and 1d316e6 bcache: implement PI controller for writeback rate, the mapping of the writeback_rate_minimum attribute was dropped. Re-add the missing sysfs writeback_rate_minimum attribute mapping to "allow the user to specify a minimum rate at which dirty blocks are retired." Fixes: 1d316e6 ("bcache: implement PI controller for writeback rate") Signed-off-by: Ben Peddell Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: add static const prefix to char * array declarations

2018-08-11T21:46:42+00:00

This patch declares char * array with const prefix in sysfs.c, which is suggested by checkpatch.pl. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: style fixes for lines over 80 characters

2018-08-11T21:46:41+00:00

This patch fixes the lines over 80 characters into more lines, to minimize warnings by checkpatch.pl. There are still some lines exceed 80 characters, but it is better to be a single line and I don't change them. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: style fix to add a blank line after declarations

2018-08-11T21:46:41+00:00

Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: style fix to replace 'unsigned' by 'unsigned int'

2018-08-11T21:46:41+00:00

This patch fixes warning reported by checkpatch.pl by replacing 'unsigned' with 'unsigned int'. Signed-off-by: Coly Li Reviewed-by: Shenghui Wang Signed-off-by: Jens Axboe

bcache: fix error setting writeback_rate through sysfs interface

2018-08-10T18:18:47+00:00

Commit ea8c5356d390 ("bcache: set max writeback rate when I/O request is idle") changes struct bch_ratelimit member rate from uint32_t to atomic_long_t and uses atomic_long_set() in drivers/md/bcache/sysfs.c to set new writeback rate, after the input is converted from memory buf to long int by sysfs_strtoul_clamp(). The above change has a problem because there is an implicit return inside sysfs_strtoul_clamp() so the following atomic_long_set() won't be called. This error is detected by 0day system with following snipped smatch warnings: drivers/md/bcache/sysfs.c:271 __cached_dev_store() error: uninitialized symbol 'v'. 270 sysfs_strtoul_clamp(writeback_rate, v, 1, INT_MAX); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @271 atomic_long_set(&dc->writeback_rate.rate, v); This patch fixes the above error by using strtoul_safe_clamp() to convert the input buffer into a long int type result. Fixes: ea8c5356d390 ("bcache: set max writeback rate when I/O request is idle") Cc: Kai Krakow Cc: Stefan Priebe Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: make the pr_err statement used for ENOENT only in sysfs_attatch section

2018-08-09T14:21:17+00:00

The pr_err statement in the code for sysfs_attatch section would run for various error codes, which maybe confusing. E.g, Run the command twice: echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \ /sys/block/bcache0/bcache/attach [the backing dev got attached on the first run] echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \ /sys/block/bcache0/bcache/attach In dmesg, after the command run twice, we can get: bcache: bch_cached_dev_attach() Can't attach sda6: already attached bcache: __cached_dev_store() Can't attach 796b5c05-b03c-4bc7-9cbd-\ a8df5e8be891 : cache set not found The first statement in the message was right, but the second was confusing. bch_cached_dev_attach has various pr_ statements for various error codes, except ENOENT. After the change, rerun above command twice: echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \ /sys/block/bcache0/bcache/attach echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be891 > \ /sys/block/bcache0/bcache/attach In dmesg we only got: bcache: bch_cached_dev_attach() Can't attach sda6: already attached No confusing "cache set not found" message anymore. And for some not exist SET-UUID: echo 796b5c05-b03c-4bc7-9cbd-a8df5e8be898 > \ /sys/block/bcache0/bcache/attach In dmesg we can get: bcache: __cached_dev_store() Can't attach 796b5c05-b03c-4bc7-9cbd-\ a8df5e8be898 : cache set not found Signed-off-by: Shenghui Wang Signed-off-by: Coly Li Signed-off-by: Jens Axboe

bcache: set max writeback rate when I/O request is idle

2018-08-09T14:21:15+00:00

Commit b1092c9af9ed ("bcache: allow quick writeback when backing idle") allows the writeback rate to be faster if there is no I/O request on a bcache device. It works well if there is only one bcache device attached to the cache set. If there are many bcache devices attached to a cache set, it may introduce performance regression because multiple faster writeback threads of the idle bcache devices will compete the btree level locks with the bcache device who have I/O requests coming. This patch fixes the above issue by only permitting fast writebac when all bcache devices attached on the cache set are idle. And if one of the bcache devices has new I/O request coming, minimized all writeback throughput immediately and let PI controller __update_writeback_rate() to decide the upcoming writeback rate for each bcache device. Also when all bcache devices are idle, limited wrieback rate to a small number is wast of thoughput, especially when backing devices are slower non-rotation devices (e.g. SATA SSD). This patch sets a max writeback rate for each backing device if the whole cache set is idle. A faster writeback rate in idle time means new I/Os may have more available space for dirty data, and people may observe a better write performance then. Please note bcache may change its cache mode in run time, and this patch still works if the cache mode is switched from writeback mode and there is still dirty data on cache. Fixes: Commit b1092c9af9ed ("bcache: allow quick writeback when backing idle") Cc: stable@vger.kernel.org #4.16+ Signed-off-by: Coly Li Tested-by: Kai Krakow Tested-by: Stefan Priebe Cc: Michael Lyle Signed-off-by: Jens Axboe

bcache: display rate debug parameters to 0 when writeback is not running

2018-08-09T14:21:03+00:00

When writeback is not running, writeback rate should be 0, other value is misleading. And the following dyanmic writeback rate debug parameters should be 0 too, rate, proportional, integral, change otherwise they are misleading when writeback is not running. Signed-off-by: Coly Li Signed-off-by: Jens Axboe

treewide: Use array_size() in vmalloc()

2018-06-12T23:19:22+00:00

The vmalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vmalloc(a * b) with: vmalloc(array_size(a, b)) as well as handling cases of: vmalloc(a * b * c) with: vmalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vmalloc(4 * 1024) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vmalloc( - sizeof(u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vmalloc( - sizeof(char) * COUNT + COUNT , ...) | vmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( vmalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vmalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( vmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( vmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( vmalloc(C1 * C2 * C3, ...) | vmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vmalloc(C1 * C2, ...) | vmalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook