LU-16713 llite: writeback/commit pages under memory pressure

[fs/lustre-release.git] / lustre / llite / rw.c

diff --git a/lustre/llite/rw.c b/lustre/llite/rw.c
index 7a6d0c3..d03a729 100644 (file)
--- a/lustre/llite/rw.c
+++ b/lustre/llite/rw.c
@@ -1555,6 +1555,7 @@ int ll_writepages(struct address_space *mapping, struct writeback_control *wbc)
        enum cl_fsync_mode mode;
        int range_whole = 0;
        int result;
+
        ENTRY;
 
        if (wbc->range_cyclic) {
@@ -1573,6 +1574,37 @@ int ll_writepages(struct address_space *mapping, struct writeback_control *wbc)
        if (wbc->sync_mode == WB_SYNC_ALL)
                mode = CL_FSYNC_LOCAL;
 
+       if (wbc->sync_mode == WB_SYNC_NONE) {
+#ifdef SB_I_CGROUPWB
+               struct bdi_writeback *wb;
+
+               /*
+                * As it may break full stripe writes on the inode,
+                * disable periodic kupdate writeback (@wbc->for_kupdate)?
+                */
+
+               /*
+                * The system is under memory pressure and it is now reclaiming
+                * cache pages.
+                */
+               wb = inode_to_wb(inode);
+               if (wbc->for_background ||
+                   (wb->start_all_reason == WB_REASON_VMSCAN &&
+                    test_bit(WB_start_all, &wb->state)))
+                       mode = CL_FSYNC_RECLAIM;
+#else
+               /*
+                * We have no idea about writeback reason for memory reclaim
+                * WB_REASON_TRY_TO_FREE_PAGES in the old kernel such as rhel7
+                * (WB_REASON_VMSCAN in the newer kernel) ...
+                * Here set mode with CL_FSYNC_RECLAIM forcely on the old
+                * kernel.
+                */
+               if (!wbc->for_kupdate)
+                       mode = CL_FSYNC_RECLAIM;
+#endif
+       }
+
        if (ll_i2info(inode)->lli_clob == NULL)
                RETURN(0);