From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
linux-fsdevel@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: [PATCH 4/4] eventfs: Shortcut eventfs_iterate() by skipping entries already read
Date: Thu, 04 Jan 2024 16:57:15 -0500 [thread overview]
Message-ID: <20240104220048.494956957@goodmis.org> (raw)
In-Reply-To: 20240104215711.924088454@goodmis.org
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
As the ei->entries array is fixed for the duration of the eventfs_inode,
it can be used to skip over already read entries in eventfs_iterate().
That is, if ctx->pos is greater than zero, there's no reason in doing the
loop across the ei->entries array for the entries less than ctx->pos.
Instead, start the lookup of the entries at the current ctx->pos.
Link: https://lore.kernel.org/all/CAHk-=wiKwDUDv3+jCsv-uacDcHDVTYsXtBR9=6sGM5mqX+DhOg@mail.gmail.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
fs/tracefs/event_inode.c | 23 ++++++++++-------------
1 file changed, 10 insertions(+), 13 deletions(-)
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index a1934e0eea3b..fdff53d5a1f8 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -746,21 +746,15 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
if (!ei || !ei_dentry)
goto out;
- ret = 0;
-
/*
* Need to create the dentries and inodes to have a consistent
* inode number.
*/
- for (i = 0; i < ei->nr_entries; i++) {
- void *cdata = ei->data;
-
- if (c > 0) {
- c--;
- continue;
- }
+ ret = 0;
- ctx->pos++;
+ /* Start at 'c' to jump over already read entries */
+ for (i = c; i < ei->nr_entries; i++, ctx->pos++) {
+ void *cdata = ei->data;
entry = &ei->entries[i];
name = entry->name;
@@ -769,7 +763,7 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
/* If ei->is_freed then just bail here, nothing more to do */
if (ei->is_freed) {
mutex_unlock(&eventfs_mutex);
- goto out_dec;
+ goto out;
}
r = entry->callback(name, &mode, &cdata, &fops);
mutex_unlock(&eventfs_mutex);
@@ -778,14 +772,17 @@ static int eventfs_iterate(struct file *file, struct dir_context *ctx)
dentry = create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops);
if (!dentry)
- goto out_dec;
+ goto out;
ino = dentry->d_inode->i_ino;
dput(dentry);
if (!dir_emit(ctx, name, strlen(name), ino, DT_REG))
- goto out_dec;
+ goto out;
}
+ /* Subtract the skipped entries above */
+ c -= min((unsigned int)c, (unsigned int)ei->nr_entries);
+
list_for_each_entry_srcu(ei_child, &ei->children, list,
srcu_read_lock_held(&eventfs_srcu)) {
--
2.42.0
prev parent reply other threads:[~2024-01-04 21:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-04 21:57 [PATCH 0/4] eventfs: More updates to eventfs_iterate() Steven Rostedt
2024-01-04 21:57 ` [PATCH 1/4] eventfs: Have eventfs_iterate() stop immediately if ei->is_freed is set Steven Rostedt
2024-01-04 21:57 ` [PATCH 2/4] eventfs: Do ctx->pos update for all iterations in eventfs_iterate() Steven Rostedt
2024-01-04 21:57 ` [PATCH 3/4] eventfs: Read ei->entries before ei->children " Steven Rostedt
2024-01-04 21:57 ` Steven Rostedt [this message]
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