Hi Everyone,
I am working on improving the MTP write performance of devices in general.
I came across this code in kernel/fs/sync.c
178<http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob;f=fs/sync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=0e51793e162ca432fc5f04178cf82b80a92c2659#l178>int
vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync)
179<http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob;f=fs/sync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=0e51793e162ca432fc5f04178cf82b80a92c2659#l179>{
180<http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob;f=fs/sync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=0e51793e162ca432fc5f04178cf82b80a92c2659#l180>
if (!file->f_op || !file->f_op->fsync)
181<http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob;f=fs/sync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=0e51793e162ca432fc5f04178cf82b80a92c2659#l181>
return -EINVAL;
182<http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob;f=fs/sync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=0e51793e162ca432fc5f04178cf82b80a92c2659#l182>
return file->f_op->fsync(file, start, end, datasync);
183<http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob;f=fs/sync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=0e51793e162ca432fc5f04178cf82b80a92c2659#l183>}
184<http://git.kernel.org/?p=linux/kernel/git/stable/linux-stable.git;a=blob;f=fs/sync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=0e51793e162ca432fc5f04178cf82b80a92c2659#l184>EXPORT_SYMBOL(vfs_fsync_range);
can someone point out what happens if I disable this code, as I see good
improvement in performance if I disable this.
Also this code has been changed in Samung's Kernel code
int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int
datasync) { struct address_space *mapping = file->f_mapping; int err, ret;
if (!file->f_op || !file->f_op->fsync) { ret = -EINVAL; goto out; } ret =
filemap_write_and_wait_range(mapping, start, end); /* * We need to protect
against concurrent writers, which could cause * livelocks in
fsync_buffers_list(). */ mutex_lock(&mapping->host->i_mutex); err =
file->f_op->fsync(file, datasync); if (!ret) ret = err;
mutex_unlock(&mapping->host->i_mutex); out: return ret; }
Can anyone point out what the additional code is doing and why. (In case
you have seen this)
Also please suggest any other option to improve MTP write performance
Thanks for your help
Mike
--
unsubscribe: [email protected]
website: http://groups.google.com/group/android-porting
