Attempt to reduce stack usage in acct.c (linux-2.6.12-rc1-mm3). Stack
usage was noted using checkstack.pl. Specifically:
Before patch
------------
check_free_space - 128
do_acct_process - 105
After patch
-----------
check_free_space - 36
do_acct_process - 44
Signed-off-by: Yum Rayan <[EMAIL PROTECTED]>
--- a/kernel/acct.c 2005-03-25 22:11:06.000000000 -0800
+++ b/kernel/acct.c 2005-03-30 15:33:05.000000000 -0800
@@ -103,30 +103,32 @@
*/
static int check_free_space(struct file *file)
{
- struct kstatfs sbuf;
- int res;
- int act;
- sector_t resume;
- sector_t suspend;
+ struct kstatfs *sbuf = NULL;
+ int res, act;
+ sector_t resume, suspend;
spin_lock(&acct_globals.lock);
res = acct_globals.active;
if (!file || !acct_globals.needcheck)
- goto out;
+ goto out_unlock;
spin_unlock(&acct_globals.lock);
+ sbuf = kmalloc(sizeof (struct kstatfs), GFP_KERNEL);
+ if (!sbuf)
+ goto out_res;
+
/* May block */
- if (vfs_statfs(file->f_dentry->d_inode->i_sb, &sbuf))
- return res;
- suspend = sbuf.f_blocks * SUSPEND;
- resume = sbuf.f_blocks * RESUME;
+ if (vfs_statfs(file->f_dentry->d_inode->i_sb, sbuf))
+ goto out_free_sbuf;
+ suspend = sbuf->f_blocks * SUSPEND;
+ resume = sbuf->f_blocks * RESUME;
sector_div(suspend, 100);
sector_div(resume, 100);
- if (sbuf.f_bavail <= suspend)
+ if (sbuf->f_bavail <= suspend)
act = -1;
- else if (sbuf.f_bavail >= resume)
+ else if (sbuf->f_bavail >= resume)
act = 1;
else
act = 0;
@@ -139,7 +141,7 @@
if (file != acct_globals.file) {
if (act)
res = act>0;
- goto out;
+ goto out_unlock;
}
if (acct_globals.active) {
@@ -159,8 +161,11 @@
acct_globals.timer.expires = jiffies + ACCT_TIMEOUT*HZ;
add_timer(&acct_globals.timer);
res = acct_globals.active;
-out:
+out_unlock:
spin_unlock(&acct_globals.lock);
+out_free_sbuf:
+ kfree(sbuf);
+out_res:
return res;
}
@@ -380,7 +385,7 @@
*/
static void do_acct_process(long exitcode, struct file *file)
{
- acct_t ac;
+ acct_t *ac;
mm_segment_t fs;
unsigned long vsize;
unsigned long flim;
@@ -395,14 +400,18 @@
if (!check_free_space(file))
return;
+ ac = kmalloc(sizeof (acct_t), GFP_KERNEL);
+ if (!ac)
+ return;
+
/*
* Fill the accounting struct with the needed info as recorded
* by the different kernel functions.
*/
- memset((caddr_t)&ac, 0, sizeof(acct_t));
+ memset(ac, 0, sizeof(acct_t));
- ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER;
- strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm));
+ ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER;
+ strlcpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm));
/* calculate run_time in nsec*/
do_posix_clock_monotonic_gettime(&uptime);
@@ -412,57 +421,57 @@
/* convert nsec -> AHZ */
elapsed = nsec_to_AHZ(run_time);
#if ACCT_VERSION==3
- ac.ac_etime = encode_float(elapsed);
+ ac->ac_etime = encode_float(elapsed);
#else
- ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
+ ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ?
(unsigned long) elapsed : (unsigned long) -1l);
#endif
#if ACCT_VERSION==1 || ACCT_VERSION==2
{
/* new enlarged etime field */
comp2_t etime = encode_comp2_t(elapsed);
- ac.ac_etime_hi = etime >> 16;
- ac.ac_etime_lo = (u16) etime;
+ ac->ac_etime_hi = etime >> 16;
+ ac->ac_etime_lo = (u16) etime;
}
#endif
do_div(elapsed, AHZ);
- ac.ac_btime = xtime.tv_sec - elapsed;
- ac.ac_utime = encode_comp_t(jiffies_to_AHZ(
+ ac->ac_btime = xtime.tv_sec - elapsed;
+ ac->ac_utime = encode_comp_t(jiffies_to_AHZ(
current->signal->utime +
current->group_leader->utime));
- ac.ac_stime = encode_comp_t(jiffies_to_AHZ(
+ ac->ac_stime = encode_comp_t(jiffies_to_AHZ(
current->signal->stime +
current->group_leader->stime));
/* we really need to bite the bullet and change layout */
- ac.ac_uid = current->uid;
- ac.ac_gid = current->gid;
+ ac->ac_uid = current->uid;
+ ac->ac_gid = current->gid;
#if ACCT_VERSION==2
- ac.ac_ahz = AHZ;
+ ac->ac_ahz = AHZ;
#endif
#if ACCT_VERSION==1 || ACCT_VERSION==2
/* backward-compatible 16 bit fields */
- ac.ac_uid16 = current->uid;
- ac.ac_gid16 = current->gid;
+ ac->ac_uid16 = current->uid;
+ ac->ac_gid16 = current->gid;
#endif
#if ACCT_VERSION==3
- ac.ac_pid = current->tgid;
- ac.ac_ppid = current->parent->tgid;
+ ac->ac_pid = current->tgid;
+ ac->ac_ppid = current->parent->tgid;
#endif
read_lock(&tasklist_lock); /* pin current->signal */
- ac.ac_tty = current->signal->tty ?
+ ac->ac_tty = current->signal->tty ?
old_encode_dev(tty_devnum(current->signal->tty)) : 0;
read_unlock(&tasklist_lock);
- ac.ac_flag = 0;
+ ac->ac_flag = 0;
if (current->flags & PF_FORKNOEXEC)
- ac.ac_flag |= AFORK;
+ ac->ac_flag |= AFORK;
if (current->flags & PF_SUPERPRIV)
- ac.ac_flag |= ASU;
+ ac->ac_flag |= ASU;
if (current->flags & PF_DUMPCORE)
- ac.ac_flag |= ACORE;
+ ac->ac_flag |= ACORE;
if (current->flags & PF_SIGNALED)
- ac.ac_flag |= AXSIG;
+ ac->ac_flag |= AXSIG;
vsize = 0;
if (current->mm) {
@@ -476,15 +485,15 @@
up_read(¤t->mm->mmap_sem);
}
vsize = vsize / 1024;
- ac.ac_mem = encode_comp_t(vsize);
- ac.ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */
- ac.ac_rw = encode_comp_t(ac.ac_io / 1024);
- ac.ac_minflt = encode_comp_t(current->signal->min_flt +
+ ac->ac_mem = encode_comp_t(vsize);
+ ac->ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */
+ ac->ac_rw = encode_comp_t(ac->ac_io / 1024);
+ ac->ac_minflt = encode_comp_t(current->signal->min_flt +
current->group_leader->min_flt);
- ac.ac_majflt = encode_comp_t(current->signal->maj_flt +
+ ac->ac_majflt = encode_comp_t(current->signal->maj_flt +
current->group_leader->maj_flt);
- ac.ac_swaps = encode_comp_t(0);
- ac.ac_exitcode = exitcode;
+ ac->ac_swaps = encode_comp_t(0);
+ ac->ac_exitcode = exitcode;
/*
* Kernel segment override to datasegment and write it
@@ -497,10 +506,11 @@
*/
flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY;
- file->f_op->write(file, (char *)&ac,
+ file->f_op->write(file, (char *)ac,
sizeof(acct_t), &file->f_pos);
current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim;
set_fs(fs);
+ kfree(ac);
}
/*
-
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