>-----Original Message-----
>From: Jaegeuk Kim [mailto:[email protected]]
>Sent: Friday, June 01, 2018 1:56 AM
>To: heyunlei
>Cc: Yuchao (T); [email protected]; Wangbintian;
>Zhangdianfang (Euler)
>Subject: Re: [f2fs-dev][PATCH RFC] Revert "f2fs: avoid cpu lockup"
>
>Hi Yunlei,
>
Hi Jaegeuk，
>On 05/31, Yunlei He wrote:
>> This reverts commit 4db08d016ccedb5b97869724a096990acad59685 to
>> fix hungtask problem which can be reproduced as follow:
>>
>> Thread 0~3:
>>
>> while true
>> do
>> touch /xxx/test/file_xxx
>> done
>>
>> Thread 5 write a new checkpoint every three seconds.
>>
>> In the meantime, fio start 16 threads for randwrite.
>>
>> With my debug info, cycles num will exceed 1000 in function
>> f2fs_sync_dirty_inodes, and most of cycle will be dropped
>> into congestion_wait() and sleep more than 20ms.
>
>Original patch tries to fix watchdog which sync_dirty_inodes() grabs one
>cpu for a long time. Have you tried reproduce that as well?
>
I have test this patch with increasing touch file threads to 32，and other remain
same as previous, But I have not reproduce your problem.
Besides, I try to test the code just remove this line:
congestion_wait(BLK_RW_ASYNC, HZ/50);
It's also ok to my test, and cycle num reduced to < 3
Thanks.
>Thanks,
>
>>
>> Signed-off-by: Yunlei He <[email protected]>
>> ---
>> fs/f2fs/checkpoint.c | 10 ----------
>> 1 file changed, 10 deletions(-)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index 8eb184c..76e1856 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -944,7 +944,6 @@ int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi,
>> enum inode_type type)
>> struct inode *inode;
>> struct f2fs_inode_info *fi;
>> bool is_dir = (type == DIR_INODE);
>> - unsigned long ino = 0;
>>
>> trace_f2fs_sync_dirty_inodes_enter(sbi->sb, is_dir,
>> get_pages(sbi, is_dir ?
>> @@ -967,8 +966,6 @@ int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi,
>> enum inode_type type)
>> inode = igrab(&fi->vfs_inode);
>> spin_unlock(&sbi->inode_lock[type]);
>> if (inode) {
>> - unsigned long cur_ino = inode->i_ino;
>> -
>> if (is_dir)
>> F2FS_I(inode)->cp_task = current;
>>
>> @@ -978,13 +975,6 @@ int f2fs_sync_dirty_inodes(struct f2fs_sb_info *sbi,
>> enum inode_type type)
>> F2FS_I(inode)->cp_task = NULL;
>>
>> iput(inode);
>> - /* We need to give cpu to another writers. */
>> - if (ino == cur_ino) {
>> - congestion_wait(BLK_RW_ASYNC, HZ/50);
>> - cond_resched();
>> - } else {
>> - ino = cur_ino;
>> - }
>> } else {
>> /*
>> * We should submit bio, since it exists several
>> --
>> 1.9.1
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
