Subject: + fput-turn-list_head-delayed_fput_list-into-llist_head.patch added to -mm tree
To: oleg@xxxxxxxxxx,a.p.zijlstra@xxxxxxxxx,akpm@xxxxxxxxxxxxxxxxxxxx,avagin@xxxxxxxxxx,dhowells@xxxxxxxxxx,ebiederm@xxxxxxxxxxxx,viro@xxxxxxxxxxxxxxxxxx,ying.huang@xxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 18 Jun 2013 14:00:42 -0700
The patch titled
Subject: fput: turn "list_head delayed_fput_list" into llist_head
has been added to the -mm tree. Its filename is
fput-turn-list_head-delayed_fput_list-into-llist_head.patch
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------------------------------------------------------
From: Oleg Nesterov <oleg@xxxxxxxxxx>
Subject: fput: turn "list_head delayed_fput_list" into llist_head
fput() and delayed_fput() can use llist and avoid the locking.
This is unlikely path, it is not that this change can improve
the performance, but this way the code looks simpler.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Suggested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrey Vagin <avagin@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/file_table.c | 25 ++++++++++---------------
include/linux/fs.h | 2 ++
2 files changed, 12 insertions(+), 15 deletions(-)
diff -puN fs/file_table.c~fput-turn-list_head-delayed_fput_list-into-llist_head fs/file_table.c
--- a/fs/file_table.c~fput-turn-list_head-delayed_fput_list-into-llist_head
+++ a/fs/file_table.c
@@ -265,18 +265,15 @@ static void __fput(struct file *file)
mntput(mnt);
}
-static DEFINE_SPINLOCK(delayed_fput_lock);
-static LIST_HEAD(delayed_fput_list);
+static LLIST_HEAD(delayed_fput_list);
static void delayed_fput(struct work_struct *unused)
{
- LIST_HEAD(head);
- spin_lock_irq(&delayed_fput_lock);
- list_splice_init(&delayed_fput_list, &head);
- spin_unlock_irq(&delayed_fput_lock);
- while (!list_empty(&head)) {
- struct file *f = list_first_entry(&head, struct file, f_u.fu_list);
- list_del_init(&f->f_u.fu_list);
- __fput(f);
+ struct llist_node *node = llist_del_all(&delayed_fput_list);
+ struct llist_node *next;
+
+ for (; node; node = next) {
+ next = llist_next(node);
+ __fput(llist_entry(node, struct file, f_u.fu_llist));
}
}
@@ -306,7 +303,6 @@ void fput(struct file *file)
{
if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
- unsigned long flags;
file_sb_list_del(file);
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
@@ -320,10 +316,9 @@ void fput(struct file *file)
* fput to avoid leaking *file.
*/
}
- spin_lock_irqsave(&delayed_fput_lock, flags);
- list_add(&file->f_u.fu_list, &delayed_fput_list);
- schedule_work(&delayed_fput_work);
- spin_unlock_irqrestore(&delayed_fput_lock, flags);
+
+ if (llist_add(&file->f_u.fu_llist, &delayed_fput_list))
+ schedule_work(&delayed_fput_work);
}
}
diff -puN include/linux/fs.h~fput-turn-list_head-delayed_fput_list-into-llist_head include/linux/fs.h
--- a/include/linux/fs.h~fput-turn-list_head-delayed_fput_list-into-llist_head
+++ a/include/linux/fs.h
@@ -10,6 +10,7 @@
#include <linux/stat.h>
#include <linux/cache.h>
#include <linux/list.h>
+#include <linux/llist.h>
#include <linux/radix-tree.h>
#include <linux/rbtree.h>
#include <linux/init.h>
@@ -767,6 +768,7 @@ struct file {
*/
union {
struct list_head fu_list;
+ struct llist_node fu_llist;
struct rcu_head fu_rcuhead;
} f_u;
struct path f_path;
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
linux-next.patch
fput-task_work_add-can-fail-if-the-caller-has-passed-exit_task_work-fix.patch
posix_cpu_timer-consolidate-expiry-time-type.patch
posix_cpu_timers-consolidate-timer-list-cleanups.patch
posix_cpu_timers-consolidate-expired-timers-check.patch
posix-timers-correctly-get-dying-task-time-sample-in-posix_cpu_timer_schedule.patch
posix_timers-fix-racy-timer-delta-caching-on-task-exit.patch
include-linux-schedh-dont-use-task-pid-tgid-in-same_thread_group-has_group_leader_pid.patch
lockdep-introduce-lock_acquire_exclusive-shared-helper-macros.patch
lglock-update-lockdep-annotations-to-report-recursive-local-locks.patch
fput-turn-list_head-delayed_fput_list-into-llist_head.patch
llist-fix-simplify-llist_add-and-llist_add_batch.patch
llist-llist_add-can-use-llist_add_batch.patch
vfree-dont-schedule-free_work-if-llist_add-returns-false.patch
kernel-sysc-do_sysinfo-use-get_monotonic_boottime.patch
autofs4-allow-autofs-to-work-outside-the-initial-pid-namespace.patch
autofs4-translate-pids-to-the-right-namespace-for-the-daemon.patch
ptrace-x86-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-powerpc-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-arm-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-sh-revert-hw_breakpoints-fix-racy-access-to-ptrace-breakpoints.patch
ptrace-revert-prepare-to-fix-racy-accesses-on-task-breakpoints.patch
ptrace-x86-simplify-the-disable-logic-in-ptrace_write_dr7.patch
ptrace-x86-dont-delay-disable-till-second-pass-in-ptrace_write_dr7.patch
ptrace-x86-introduce-ptrace_register_breakpoint.patch
ptrace-x86-ptrace_write_dr7-should-create-bp-if-disabled.patch
ptrace-x86-cleanup-ptrace_set_debugreg.patch
ptrace-ptrace_detach-should-do-flush_ptrace_hw_breakpointchild.patch
ptrace-x86-flush_ptrace_hw_breakpoint-shoule-clear-the-virtual-debug-registers.patch
x86-kill-tif_debug.patch
ptrace-add-ability-to-get-set-signal-blocked-mask.patch
usermodehelper-kill-the-sub_info-path-check.patch
coredump-format_corename-can-leak-cn-corename.patch
coredump-introduce-cn_vprintf.patch
coredump-cn_vprintf-has-no-reason-to-call-vsnprintf-twice.patch
coredump-kill-cn_escape-introduce-cn_esc_printf.patch
coredump-kill-call_count-add-core_name_size.patch
coredump-%-at-the-end-shouldnt-bypass-core_uses_pid-logic.patch
coredump-%-at-the-end-shouldnt-bypass-core_uses_pid-logic-fix.patch
fs-execc-de_thread-use-change_pid-rather-than-detach_pid-attach_pid.patch
move-exit_task_namespaces-outside-of-exit_notify-fix.patch
exitc-unexport-__set_special_pids.patch
fs-proc-uptimec-uptime_proc_show-use-get_monotonic_boottime.patch
kernel-forkc-copy_process-unify-clone_thread-or-thread_group_leader-code.patch
kernel-forkc-copy_process-dont-add-the-uninitialized-child-to-thread-task-pid-lists.patch
kernel-forkc-copy_process-consolidate-the-lockless-clone_thread-checks.patch
fs-execc-do_execve_common-use-current_user.patch
fs-execc-de_thread-mt-exec-should-update-real_start_time.patch
wait-introduce-wait_event_commonwq-condition-state-timeout.patch
wait-introduce-wait_event_commonwq-condition-state-timeout-checkpatch-fixes.patch
wait-introduce-prepare_to_wait_event.patch
wait-introduce-prepare_to_wait_event-checkpatch-fixes.patch
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