From cfd73237722135807967f389bcbda558a60a30d6 Mon Sep 17 00:00:00 2001 From: Alex Zhuravlev Date: Tue, 21 Apr 2020 10:54:07 +0300 Subject: ext4: add prefetching for block allocation bitmaps This should significantly improve bitmap loading, especially for flex groups as it tries to load all bitmaps within a flex.group instead of one by one synchronously. Prefetching is done in 8 * flex_bg groups, so it should be 8 read-ahead reads for a single allocating thread. At the end of allocation the thread waits for read-ahead completion and initializes buddy information so that read-aheads are not lost in case of memory pressure. At cr=0 the number of prefetching IOs is limited per allocation context to prevent a situation when mballoc loads thousands of bitmaps looking for a perfect group and ignoring groups with good chunks. Together with the patch "ext4: limit scanning of uninitialized groups" the mount time (which includes few tiny allocations) of a 1PB filesystem is reduced significantly: 0% full 50%-full unpatched patched mount time 33s 9279s 563s [ Restructured by tytso; removed the state flags in the allocation context, so it can be used to lazily prefetch the allocation bitmaps immediately after the file system is mounted. Skip prefetching block groups which are uninitialized. Finally pass in the REQ_RAHEAD flag to the block layer while prefetching. ] Signed-off-by: Alex Zhuravlev Reviewed-by: Andreas Dilger Signed-off-by: Theodore Ts'o --- fs/ext4/sysfs.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/ext4/sysfs.c') diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index 6c9fc9e21c13..31e0db726d21 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -240,6 +240,8 @@ EXT4_RO_ATTR_ES_STRING(last_error_func, s_last_error_func, 32); EXT4_ATTR(first_error_time, 0444, first_error_time); EXT4_ATTR(last_error_time, 0444, last_error_time); EXT4_ATTR(journal_task, 0444, journal_task); +EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch); +EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit); static unsigned int old_bump_val = 128; EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val); @@ -283,6 +285,8 @@ static struct attribute *ext4_attrs[] = { #ifdef CONFIG_EXT4_DEBUG ATTR_LIST(simulate_fail), #endif + ATTR_LIST(mb_prefetch), + ATTR_LIST(mb_prefetch_limit), NULL, }; ATTRIBUTE_GROUPS(ext4); -- cgit From 1cf006ed19a887c22e085189c8b4a3cbf60d2246 Mon Sep 17 00:00:00 2001 From: Dmitry Monakhov Date: Sat, 25 Jul 2020 12:33:13 +0000 Subject: ext4: export msg_count and warning_count via sysfs This numbers can be analized by system automation similar to errors_count. In ideal world it would be nice to have separate counters for different log-levels, but this makes this patch too intrusive. Signed-off-by: Dmitry Monakhov Link: https://lore.kernel.org/r/20200725123313.4467-1-dmtrmonakhov@yandex-team.ru Signed-off-by: Theodore Ts'o --- fs/ext4/sysfs.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'fs/ext4/sysfs.c') diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index 31e0db726d21..7fee11cc30e7 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -189,6 +189,9 @@ static struct ext4_attr ext4_attr_##_name = { \ #define EXT4_RW_ATTR_SBI_UL(_name,_elname) \ EXT4_ATTR_OFFSET(_name, 0644, pointer_ul, ext4_sb_info, _elname) +#define EXT4_RO_ATTR_SBI_ATOMIC(_name,_elname) \ + EXT4_ATTR_OFFSET(_name, 0444, pointer_atomic, ext4_sb_info, _elname) + #define EXT4_ATTR_PTR(_name,_mode,_id,_ptr) \ static struct ext4_attr ext4_attr_##_name = { \ .attr = {.name = __stringify(_name), .mode = _mode }, \ @@ -226,6 +229,8 @@ EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst); #ifdef CONFIG_EXT4_DEBUG EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail); #endif +EXT4_RO_ATTR_SBI_ATOMIC(warning_count, s_warning_count); +EXT4_RO_ATTR_SBI_ATOMIC(msg_count, s_msg_count); EXT4_RO_ATTR_ES_UI(errors_count, s_error_count); EXT4_RO_ATTR_ES_U8(first_error_errcode, s_first_error_errcode); EXT4_RO_ATTR_ES_U8(last_error_errcode, s_last_error_errcode); @@ -269,6 +274,8 @@ static struct attribute *ext4_attrs[] = { ATTR_LIST(msg_ratelimit_interval_ms), ATTR_LIST(msg_ratelimit_burst), ATTR_LIST(errors_count), + ATTR_LIST(warning_count), + ATTR_LIST(msg_count), ATTR_LIST(first_error_ino), ATTR_LIST(last_error_ino), ATTR_LIST(first_error_block), -- cgit From 27bc446e2def38db3244a6eb4bb1d6312936610a Mon Sep 17 00:00:00 2001 From: brookxu Date: Mon, 17 Aug 2020 15:36:15 +0800 Subject: ext4: limit the length of per-inode prealloc list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In the scenario of writing sparse files, the per-inode prealloc list may be very long, resulting in high overhead for ext4_mb_use_preallocated(). To circumvent this problem, we limit the maximum length of per-inode prealloc list to 512 and allow users to modify it. After patching, we observed that the sys ratio of cpu has dropped, and the system throughput has increased significantly. We created a process to write the sparse file, and the running time of the process on the fixed kernel was significantly reduced, as follows: Running time on unfixed kernel： [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat real 0m2.051s user 0m0.008s sys 0m2.026s Running time on fixed kernel： [root@TENCENT64 ~]# time taskset 0x01 ./sparse /data1/sparce.dat real 0m0.471s user 0m0.004s sys 0m0.395s Signed-off-by: Chunguang Xu Link: https://lore.kernel.org/r/d7a98178-056b-6db5-6bce-4ead23f4a257@gmail.com Signed-off-by: Theodore Ts'o --- fs/ext4/sysfs.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/ext4/sysfs.c') diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index 7fee11cc30e7..bfabb799fa45 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -218,6 +218,7 @@ EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan); EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs); EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request); EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc); +EXT4_RW_ATTR_SBI_UI(mb_max_inode_prealloc, s_mb_max_inode_prealloc); EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb); EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error); EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval); @@ -264,6 +265,7 @@ static struct attribute *ext4_attrs[] = { ATTR_LIST(mb_order2_req), ATTR_LIST(mb_stream_req), ATTR_LIST(mb_group_prealloc), + ATTR_LIST(mb_max_inode_prealloc), ATTR_LIST(max_writeback_mb_bump), ATTR_LIST(extent_max_zeroout_kb), ATTR_LIST(trigger_fs_error), -- cgit