From: Sahitya Tummala Date: Wed, 15 Apr 2020 09:07:53 +0000 (+0530) Subject: f2fs: fix long latency due to discard during umount X-Git-Tag: rel_imx_5.10.35_2.0.0-somdevices.0~1966^2~48 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=141af6ba5216d4d49de683582b600d5c9b51792c;p=linux.git f2fs: fix long latency due to discard during umount 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 Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index b7a9421472a7..90c75822fef6 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -1101,7 +1101,6 @@ 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; @@ -1463,6 +1462,8 @@ next: return issued; } +static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi, + struct discard_policy *dpolicy); static int __issue_discard_cmd(struct f2fs_sb_info *sbi, struct discard_policy *dpolicy) @@ -1471,12 +1472,14 @@ 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) f2fs_update_time(sbi, UMOUNT_DISCARD_TIMEOUT); +retry: + issued = 0; for (i = MAX_PLIST_NUM - 1; i >= 0; i--) { if (dpolicy->timeout && f2fs_time_over(sbi, UMOUNT_DISCARD_TIMEOUT)) @@ -1523,6 +1526,11 @@ next: break; } + if (dpolicy->type == DPOLICY_UMOUNT && issued) { + __wait_all_discard_cmd(sbi, dpolicy); + goto retry; + } + if (!issued && io_interrupted) issued = -1;