The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.24
------>
commit 97917a7229cd315e8433ac9b33168a4cfdae193b
Author: Kirill Tkhai <ktk...@virtuozzo.com>
Date: Fri Apr 30 13:52:41 2021 +0300
ve/fs/files: Add new argument to expand_files()
Patchset description:
Shrink big fdtable on criu restore
This patchset allows to avoid memory overuse introduced by service fds on
criu
restore.
The solution is simple: smartly check for closed fd number, and shrink
fdtable
if this could be made. The checks are happen in is_pseudosuper mode, so we
do
not affect performance on normal work mode.
The problem is we can't solve this for 100% case in userspace.
Kernel allows to fix that completely.
https://jira.sw.ru/browse/PSBM-78827
Eric Dumazet (1):
ms/fs/file.c: don't acquire files->file_lock in fd_install()
Kirill Tkhai (3):
files: Add new argument to expand_files()
files: Add fdtable_align() helper
files: Shrink big fdtable on close in is_pseudosuper mode
Mateusz Guzik (1):
ms/vfs: grab the lock instead of blocking in __fd_install during
resizing
============================================================
This patch description:
Add argument "shrink" to the functions.
This is refactoring, which will be used in next patches.
Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
Reviewed-by: Cyrill Gorcunov <gorcu...@openvz.org>
(cherry picked from vz7 commit 997f6cab4a45 ("ve/fs/files: Add new argument
to
expand_files()"))
Signed-off-by: Andrey Zhadchenko <andrey.zhadche...@virtuozzo.com>
---
fs/file.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/fs/file.c b/fs/file.c
index 915f7ad2a5b5..866912fd02d6 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -68,7 +68,7 @@ static void copy_fd_bitmaps(struct fdtable *nfdt, struct
fdtable *ofdt,
* Copy all file descriptors from the old table to the new, expanded table and
* clear the extra space. Called with the files spinlock held for write.
*/
-static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt)
+static void copy_fdtable(struct fdtable *nfdt, struct fdtable *ofdt, bool
shrink)
{
unsigned int cpy, set;
@@ -145,7 +145,7 @@ static struct fdtable * alloc_fdtable(unsigned int nr)
* Return <0 error code on error; 1 on successful completion.
* The files->file_lock should be held on entry, and will be held on exit.
*/
-static int expand_fdtable(struct files_struct *files, unsigned int nr)
+static int expand_fdtable(struct files_struct *files, unsigned int nr, bool
shrink)
__releases(files->file_lock)
__acquires(files->file_lock)
{
@@ -173,7 +173,7 @@ static int expand_fdtable(struct files_struct *files,
unsigned int nr)
}
cur_fdt = files_fdtable(files);
BUG_ON(nr < cur_fdt->max_fds);
- copy_fdtable(new_fdt, cur_fdt);
+ copy_fdtable(new_fdt, cur_fdt, shrink);
rcu_assign_pointer(files->fdt, new_fdt);
if (cur_fdt != &files->fdtab)
call_rcu(&cur_fdt->rcu, free_fdtable_rcu);
@@ -190,7 +190,7 @@ static int expand_fdtable(struct files_struct *files,
unsigned int nr)
* expanded and execution may have blocked.
* The files->file_lock should be held on entry, and will be held on exit.
*/
-static int expand_files(struct files_struct *files, unsigned int nr)
+static int expand_files(struct files_struct *files, unsigned int nr, bool
shrink)
__releases(files->file_lock)
__acquires(files->file_lock)
{
@@ -218,7 +218,7 @@ static int expand_files(struct files_struct *files,
unsigned int nr)
/* All good, so we try */
files->resize_in_progress = true;
- expanded = expand_fdtable(files, nr);
+ expanded = expand_fdtable(files, nr, shrink);
files->resize_in_progress = false;
wake_up_all(&files->resize_wait);
@@ -501,7 +501,7 @@ int __alloc_fd(struct files_struct *files,
if (fd >= end)
goto out;
- error = expand_files(files, fd);
+ error = expand_files(files, fd, false);
if (error < 0)
goto out;
@@ -900,7 +900,7 @@ int replace_fd(unsigned fd, struct file *file, unsigned
flags)
return -EBADF;
spin_lock(&files->file_lock);
- err = expand_files(files, fd);
+ err = expand_files(files, fd, false);
if (unlikely(err < 0))
goto out_unlock;
return do_dup2(files, file, fd, flags);
@@ -926,7 +926,7 @@ static int ksys_dup3(unsigned int oldfd, unsigned int
newfd, int flags)
return -EBADF;
spin_lock(&files->file_lock);
- err = expand_files(files, newfd);
+ err = expand_files(files, newfd, false);
file = fcheck(oldfd);
if (unlikely(!file))
goto Ebadf;
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