Messages in this thread Patch in this message | | | From | Sahitya Tummala <> | Subject | [PATCH v4] f2fs: fix long latency due to discard during umount | Date | Wed, 15 Apr 2020 09:01:02 +0530 |
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F2FS already has a default timeout of 5 secs for discards that can be issued during umount, but it can take more than the 5 sec timeout if the underlying UFS device queue is already full and there are no more available free tags to be used. Fix this by submitting a small batch of discard requests so that it won't cause the device queue to be full at any time and thus doesn't incur its wait time in the umount context.
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> --- v4: -Implement as per Jaegeuk's Suggestion to control the number of outstanding discard requests.
fs/f2fs/segment.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 1a62b27..764bab5 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1099,7 +1099,6 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi, } else if (discard_type == DPOLICY_FSTRIM) { dpolicy->io_aware = false; } else if (discard_type == DPOLICY_UMOUNT) { - dpolicy->max_requests = UINT_MAX; dpolicy->io_aware = false; /* we need to issue all to keep CP_TRIMMED_FLAG */ dpolicy->granularity = 1; @@ -1470,12 +1469,14 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, struct list_head *pend_list; struct discard_cmd *dc, *tmp; struct blk_plug plug; - int i, issued = 0; + int i, issued; bool io_interrupted = false; if (dpolicy->timeout != 0) f2fs_update_time(sbi, dpolicy->timeout); +retry: + issued = 0; for (i = MAX_PLIST_NUM - 1; i >= 0; i--) { if (dpolicy->timeout != 0 && f2fs_time_over(sbi, dpolicy->timeout)) @@ -1522,6 +1523,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, break; } + if (dpolicy->type == DPOLICY_UMOUNT && issued) { + __wait_all_discard_cmd(sbi, dpolicy); + goto retry; + } + if (!issued && io_interrupted) issued = -1; -- Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
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