Wind River Support Network

Description

jffs2 gc thread take huge cpu resource on powerpc target with WRLinux 6.0

Workaround

After analysis and testing, customer found there is always nod info was not be del, just set null to node:
/*************************************************/
int jffs2_do_link (struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f, uint32_t ino, uint8_t type, const char *name, int namelen, uint32_t time)
…….
mutex_lock(&c->alloc_sem);
              mutex_lock(&dir_f->sem);

              for (fd = dir_f->dents; fd; fd = fd->next) {
                       if (fd->nhash == nhash &&
                           !memcmp(fd->name, name, namelen) &&
                           !fd->name[namelen]) {
                           
                                jffs2_mark_node_obsolete(c, fd->raw);
                                /* We don't want to remove it from the list immediately,
                                   because that screws up getdents()/seek() semantics even
                                   more than they're screwed already. Turn it into a
                                   node-less deletion dirent instead -- a placeholder */
                                fd->raw = NULL; ?? ???GC??????????????
                                fd->ino = 0;
                                break;
                       }
              }
              mutex_unlock(&dir_f->sem);
/*************************************************/

They try to set fd node ino to -, and remove fd node from list when fd->raw set to NULL, I put the detailed modification snapshot in attachment for refer.
After modification, looks this kind of issue was not there. 

Steps to Reproduce

${WRL_DIR}/wrlinux-6/wrlinux/configure --enable-board=${LOCAL_CPU_TYPE} --enable-kernel=standard --enable-rootfs=glibc_small --with-template=feature/build_libc --enable-jobs=12 --enable-parallel-pkgbuilds=8 --with-layer=${PATCH_DIR}/osc-patch/osc-glibc-patch-layer --with-rcpl-version=${RCPL_VERSION}

This issue happen on customer side by far, it random happen in their lab with the following script:
/***********************************************/
 while [ True ];do

                   touch /opt/vrpv8/var/log/`cat /dev/urandom | head -n 10 | md5sum | head -c 10`.html

                   let x++  

                   sleep 1

                   rm -rf /opt/vrpv8/var/log/*.html

                   sleep 1

                   if [ 10000 -eq $x ]; then                                                                                           

                            exit

                   fi                                            

done 
/***********************************************/

Other Downloads

• Wind River Linux 6.0.0.37
• Wind River Linux 6.0.0.38