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FROMGIT: f2fs: move f2fs to use reader-unfair rwsems

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f2fs rw_semaphores work better if writers can starve readers,
especially for the checkpoint thread, because writers are strictly
more important than reader threads. This prevents significant priority
inversion between low-priority readers that blocked while trying to
acquire the read lock and a second acquisition of the write lock that
might be blocking high priority work.

Bug: 214413989
Signed-off-by: Tim Murray <timmurray@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
(cherry picked from commit e4544b63a7ee49e7fbebf35ece0a6acd3b9617ae
  git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git dev)
Change-Id: Ia0eb86447488c5ba9845a6b2eb98652200e08281
This commit is contained in:
Tim Murray
2022-01-07 12:48:44 -08:00
committed by Jaegeuk Kim
parent 23686f5ee8
commit 7e6f112beb
16 changed files with 370 additions and 301 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
fs/f2fs/checkpoint.c
View File

@@ -350,13 +350,13 @@ static int f2fs_write_meta_pages(struct address_space *mapping,
goto skip_write;
/* if locked failed, cp will flush dirty pages instead */
if (!down_write_trylock(&sbi->cp_global_sem))
if (!f2fs_down_write_trylock(&sbi->cp_global_sem))
goto skip_write;
trace_f2fs_writepages(mapping->host, wbc, META);
diff = nr_pages_to_write(sbi, META, wbc);
written = f2fs_sync_meta_pages(sbi, META, wbc->nr_to_write, FS_META_IO);
up_write(&sbi->cp_global_sem);
f2fs_up_write(&sbi->cp_global_sem);
wbc->nr_to_write = max((long)0, wbc->nr_to_write - written - diff);
return 0;
@@ -1148,7 +1148,8 @@ static bool __need_flush_quota(struct f2fs_sb_info *sbi)
if (!is_journalled_quota(sbi))
return false;
down_write(&sbi->quota_sem);
if (!f2fs_down_write_trylock(&sbi->quota_sem))
return true;
if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH)) {
ret = false;
} else if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR)) {
@@ -1159,7 +1160,7 @@ static bool __need_flush_quota(struct f2fs_sb_info *sbi)
} else if (get_pages(sbi, F2FS_DIRTY_QDATA)) {
ret = true;
}
up_write(&sbi->quota_sem);
f2fs_up_write(&sbi->quota_sem);
return ret;
}
@@ -1216,10 +1217,10 @@ retry_flush_dents:
* POR: we should ensure that there are no dirty node pages
* until finishing nat/sit flush. inode->i_blocks can be updated.
*/
down_write(&sbi->node_change);
f2fs_down_write(&sbi->node_change);
if (get_pages(sbi, F2FS_DIRTY_IMETA)) {
up_write(&sbi->node_change);
f2fs_up_write(&sbi->node_change);
f2fs_unlock_all(sbi);
err = f2fs_sync_inode_meta(sbi);
if (err)
@@ -1229,15 +1230,15 @@ retry_flush_dents:
}
retry_flush_nodes:
down_write(&sbi->node_write);
f2fs_down_write(&sbi->node_write);
if (get_pages(sbi, F2FS_DIRTY_NODES)) {
up_write(&sbi->node_write);
f2fs_up_write(&sbi->node_write);
atomic_inc(&sbi->wb_sync_req[NODE]);
err = f2fs_sync_node_pages(sbi, &wbc, false, FS_CP_NODE_IO);
atomic_dec(&sbi->wb_sync_req[NODE]);
if (err) {
up_write(&sbi->node_change);
f2fs_up_write(&sbi->node_change);
f2fs_unlock_all(sbi);
return err;
}
@@ -1250,13 +1251,13 @@ retry_flush_nodes:
* dirty node blocks and some checkpoint values by block allocation.
*/
__prepare_cp_block(sbi);
up_write(&sbi->node_change);
f2fs_up_write(&sbi->node_change);
return err;
}
static void unblock_operations(struct f2fs_sb_info *sbi)
{
up_write(&sbi->node_write);
f2fs_up_write(&sbi->node_write);
f2fs_unlock_all(sbi);
}
@@ -1591,7 +1592,7 @@ int f2fs_write_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
f2fs_warn(sbi, "Start checkpoint disabled!");
}
if (cpc->reason != CP_RESIZE)
down_write(&sbi->cp_global_sem);
f2fs_down_write(&sbi->cp_global_sem);
if (!is_sbi_flag_set(sbi, SBI_IS_DIRTY) &&
((cpc->reason & CP_FASTBOOT) || (cpc->reason & CP_SYNC) ||
@@ -1666,7 +1667,7 @@ stop:
trace_f2fs_write_checkpoint(sbi->sb, cpc->reason, "finish checkpoint");
out:
if (cpc->reason != CP_RESIZE)
up_write(&sbi->cp_global_sem);
f2fs_up_write(&sbi->cp_global_sem);
return err;
}
@@ -1714,9 +1715,9 @@ static int __write_checkpoint_sync(struct f2fs_sb_info *sbi)
struct cp_control cpc = { .reason = CP_SYNC, };
int err;
down_write(&sbi->gc_lock);
f2fs_down_write(&sbi->gc_lock);
err = f2fs_write_checkpoint(sbi, &cpc);
up_write(&sbi->gc_lock);
f2fs_up_write(&sbi->gc_lock);
return err;
}
@@ -1804,9 +1805,9 @@ int f2fs_issue_checkpoint(struct f2fs_sb_info *sbi)
if (!test_opt(sbi, MERGE_CHECKPOINT) || cpc.reason != CP_SYNC) {
int ret;
down_write(&sbi->gc_lock);
f2fs_down_write(&sbi->gc_lock);
ret = f2fs_write_checkpoint(sbi, &cpc);
up_write(&sbi->gc_lock);
f2fs_up_write(&sbi->gc_lock);
return ret;
}