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Date: Wed, 27 May 2020 10:35:35 +0800 From: Chao Yu <yuchao0@...wei.com> To: Jaegeuk Kim <jaegeuk@...nel.org> CC: <kernel-team@...roid.com>, <linux-kernel@...r.kernel.org>, <linux-f2fs-devel@...ts.sourceforge.net> Subject: Re: [f2fs-dev] [PATCH v3] f2fs: avoid inifinite loop to wait for flushing node pages at cp_error On 2020/5/26 9:56, Jaegeuk Kim wrote: > On 05/26, Chao Yu wrote: >> On 2020/5/26 9:11, Chao Yu wrote: >>> On 2020/5/25 23:06, Jaegeuk Kim wrote: >>>> On 05/25, Chao Yu wrote: >>>>> On 2020/5/25 11:56, Jaegeuk Kim wrote: >>>>>> Shutdown test is somtimes hung, since it keeps trying to flush dirty node pages 71.07% 0.01% kworker/u256:1+ [kernel.kallsyms] [k] wb_writeback | --71.06%--wb_writeback | |--68.96%--__writeback_inodes_wb | | | --68.95%--writeback_sb_inodes | | | |--65.08%--__writeback_single_inode | | | | | --64.35%--do_writepages | | | | | |--59.83%--f2fs_write_node_pages | | | | | | | --59.74%--f2fs_sync_node_pages | | | | | | | |--27.91%--pagevec_lookup_range_tag | | | | | | | | | --27.90%--find_get_pages_range_tag Before umount, kworker will always hold one core, that looks not reasonable, to avoid that, could we just allow node write, since it's out-place-update, and cp is not allowed, we don't need to worry about its effect on data on previous checkpoint, and it can decrease memory footprint cost by node pages. Thanks, >>>>> >>>>> IMO, for umount case, we should drop dirty reference and dirty pages on meta/data >>>>> pages like we change for node pages to avoid potential dead loop... >>>> >>>> I believe we're doing for them. :P >>> >>> Actually, I mean do we need to drop dirty meta/data pages explicitly as below: >>> >>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c >>> index 3dc3ac6fe143..4c08fd0a680a 100644 >>> --- a/fs/f2fs/checkpoint.c >>> +++ b/fs/f2fs/checkpoint.c >>> @@ -299,8 +299,15 @@ static int __f2fs_write_meta_page(struct page *page, >>> >>> trace_f2fs_writepage(page, META); >>> >>> - if (unlikely(f2fs_cp_error(sbi))) >>> + if (unlikely(f2fs_cp_error(sbi))) { >>> + if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) { >>> + ClearPageUptodate(page); >>> + dec_page_count(sbi, F2FS_DIRTY_META); >>> + unlock_page(page); >>> + return 0; >>> + } >>> goto redirty_out; >>> + } >>> if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) >>> goto redirty_out; >>> if (wbc->for_reclaim && page->index < GET_SUM_BLOCK(sbi, 0)) >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index 48a622b95b76..94b342802513 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -2682,6 +2682,12 @@ int f2fs_write_single_data_page(struct page *page, int *submitted, >>> >>> /* we should bypass data pages to proceed the kworkder jobs */ >>> if (unlikely(f2fs_cp_error(sbi))) { >>> + if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) { >>> + ClearPageUptodate(page); >>> + inode_dec_dirty_pages(inode); >>> + unlock_page(page); >>> + return 0; >>> + } >> >> Oh, I notice previously, we will drop non-directory inode's dirty pages directly, >> however, during umount, we'd better drop directory inode's dirty pages as well, right? > > Hmm, I remember I dropped them before. Need to double check. > >> >>> mapping_set_error(page->mapping, -EIO); >>> /* >>> * don't drop any dirty dentry pages for keeping lastest >>> >>>> >>>>> >>>>> Thanks, >>>>> >>>>>> in an inifinite loop. Let's drop dirty pages at umount in that case. >>>>>> >>>>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org> >>>>>> --- >>>>>> v3: >>>>>> - fix wrong unlock >>>>>> >>>>>> v2: >>>>>> - fix typos >>>>>> >>>>>> fs/f2fs/node.c | 9 ++++++++- >>>>>> 1 file changed, 8 insertions(+), 1 deletion(-) >>>>>> >>>>>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c >>>>>> index e632de10aedab..e0bb0f7e0506e 100644 >>>>>> --- a/fs/f2fs/node.c >>>>>> +++ b/fs/f2fs/node.c >>>>>> @@ -1520,8 +1520,15 @@ static int __write_node_page(struct page *page, bool atomic, bool *submitted, >>>>>> >>>>>> trace_f2fs_writepage(page, NODE); >>>>>> >>>>>> - if (unlikely(f2fs_cp_error(sbi))) >>>>>> + if (unlikely(f2fs_cp_error(sbi))) { >>>>>> + if (is_sbi_flag_set(sbi, SBI_IS_CLOSE)) { >>>>>> + ClearPageUptodate(page); >>>>>> + dec_page_count(sbi, F2FS_DIRTY_NODES); >>>>>> + unlock_page(page); >>>>>> + return 0; >>>>>> + } >>>>>> goto redirty_out; >>>>>> + } >>>>>> >>>>>> if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING))) >>>>>> goto redirty_out; >>>>>> >>>> . >>>> >>> >>> >>> _______________________________________________ >>> Linux-f2fs-devel mailing list >>> Linux-f2fs-devel@...ts.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel >>> . >>> > . >
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