From: Gautham Ananthakrishna <gautham.ananthakrishna@oracle.com>
To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org
Cc: viro@zeniv.linux.org.uk, matthew.wilcox@oracle.com,
khlebnikov@yandex-team.ru, gautham.ananthakrishna@oracle.com
Subject: [PATCH RFC 4/6] dcache: stop walking siblings if remaining dentries all negative
Date: Thu, 21 Jan 2021 18:49:43 +0530 [thread overview]
Message-ID: <1611235185-1685-5-git-send-email-gautham.ananthakrishna@oracle.com> (raw)
In-Reply-To: <1611235185-1685-1-git-send-email-gautham.ananthakrishna@oracle.com>
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Most walkers are interested only in positive dentries.
Changes in simple_* libfs helpers are mostly cosmetic: it shouldn't cache
negative dentries unless uses d_delete other than always_delete_dentry().
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Gautham Ananthakrishna <gautham.ananthakrishna@oracle.com>
---
fs/dcache.c | 9 +++++++++
fs/libfs.c | 3 +++
2 files changed, 12 insertions(+)
diff --git a/fs/dcache.c b/fs/dcache.c
index 894e6da..492a42f 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1459,6 +1459,8 @@ static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry)
struct check_mount *info = data;
struct path path = { .mnt = info->mnt, .dentry = dentry };
+ if (d_is_tail_negative(dentry))
+ return D_WALK_SKIP_SIBLINGS;
if (likely(!d_mountpoint(dentry)))
return D_WALK_CONTINUE;
if (__path_is_mountpoint(&path)) {
@@ -1705,6 +1707,10 @@ void shrink_dcache_for_umount(struct super_block *sb)
static enum d_walk_ret find_submount(void *_data, struct dentry *dentry)
{
struct dentry **victim = _data;
+
+ if (d_is_tail_negative(dentry))
+ return D_WALK_SKIP_SIBLINGS;
+
if (d_mountpoint(dentry)) {
__dget_dlock(dentry);
*victim = dentry;
@@ -3174,6 +3180,9 @@ static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry)
{
struct dentry *root = data;
if (dentry != root) {
+ if (d_is_tail_negative(dentry))
+ return D_WALK_SKIP_SIBLINGS;
+
if (d_unhashed(dentry) || !dentry->d_inode)
return D_WALK_SKIP;
diff --git a/fs/libfs.c b/fs/libfs.c
index 7124c2e..15d5ecf 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -410,6 +410,9 @@ int simple_empty(struct dentry *dentry)
spin_lock(&dentry->d_lock);
list_for_each_entry(child, &dentry->d_subdirs, d_child) {
+ if (d_is_tail_negative(child))
+ break;
+
spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED);
if (simple_positive(child)) {
spin_unlock(&child->d_lock);
--
1.8.3.1
next prev parent reply other threads:[~2021-01-21 15:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 13:19 [PATCH RFC 0/6] fix the negative dentres bloating system memory usage Gautham Ananthakrishna
2021-01-21 13:19 ` [PATCH RFC 1/6] dcache: sweep cached negative dentries to the end of list of siblings Gautham Ananthakrishna
2021-04-14 3:00 ` Al Viro
2021-04-15 16:50 ` Al Viro
2021-04-14 3:41 ` Al Viro
2021-04-15 16:25 ` Al Viro
2021-01-21 13:19 ` [PATCH RFC 2/6] fsnotify: stop walking child dentries if remaining tail is negative Gautham Ananthakrishna
2021-01-21 13:19 ` [PATCH RFC 3/6] dcache: add action D_WALK_SKIP_SIBLINGS to d_walk() Gautham Ananthakrishna
2021-01-21 13:19 ` Gautham Ananthakrishna [this message]
2021-01-21 13:19 ` [PATCH RFC 5/6] dcache: push releasing dentry lock into sweep_negative Gautham Ananthakrishna
2021-01-21 13:19 ` [PATCH RFC 6/6] dcache: prevent flooding with negative dentries Gautham Ananthakrishna
2021-04-14 3:56 ` Al Viro
2021-03-31 14:23 ` [PATCH RFC 0/6] fix the negative dentres bloating system memory usage Matthew Wilcox
2021-04-14 2:40 ` Al Viro
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