https://github.com/torvalds/linux
Revision c702418f8a2fa6cc92e84a39880d458faf7af9cc authored by Johannes Weiner on 04 December 2012, 16:11:31 UTC, committed by Linus Torvalds on 06 December 2012, 19:29:57 UTC
When a zone meets its high watermark and is compactable in case of higher order allocations, it contributes to the percentage of the node's memory that is considered balanced. This requirement, that a node be only partially balanced, came about when kswapd was desparately trying to balance tiny zones when all bigger zones in the node had plenty of free memory. Arguably, the same should apply to compaction: if a significant part of the node is balanced enough to run compaction, do not get hung up on that tiny zone that might never get in shape. When the compaction logic in kswapd is reached, we know that at least 25% of the node's memory is balanced properly for compaction (see zone_balanced and pgdat_balanced). Remove the individual zone checks that restart the kswapd cycle. Otherwise, we may observe more endless looping in kswapd where the compaction code loops back to reclaim because of a single zone and reclaim does nothing because the node is considered balanced overall. See for example https://bugzilla.redhat.com/show_bug.cgi?id=866988 Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-and-tested-by: Thorsten Leemhuis <fedora@leemhuis.info> Reported-by: Jiri Slaby <jslaby@suse.cz> Tested-by: John Ellson <john.ellson@comcast.net> Tested-by: Zdenek Kabelac <zkabelac@redhat.com> Tested-by: Bruno Wolff III <bruno@wolff.to> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 60177d3
Tip revision: c702418f8a2fa6cc92e84a39880d458faf7af9cc authored by Johannes Weiner on 04 December 2012, 16:11:31 UTC
mm: vmscan: do not keep kswapd looping forever due to individual uncompactable zones
mm: vmscan: do not keep kswapd looping forever due to individual uncompactable zones
Tip revision: c702418
statfs.c
#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/statfs.h>
#include <linux/security.h>
#include <linux/uaccess.h>
#include "internal.h"
static int flags_by_mnt(int mnt_flags)
{
int flags = 0;
if (mnt_flags & MNT_READONLY)
flags |= ST_RDONLY;
if (mnt_flags & MNT_NOSUID)
flags |= ST_NOSUID;
if (mnt_flags & MNT_NODEV)
flags |= ST_NODEV;
if (mnt_flags & MNT_NOEXEC)
flags |= ST_NOEXEC;
if (mnt_flags & MNT_NOATIME)
flags |= ST_NOATIME;
if (mnt_flags & MNT_NODIRATIME)
flags |= ST_NODIRATIME;
if (mnt_flags & MNT_RELATIME)
flags |= ST_RELATIME;
return flags;
}
static int flags_by_sb(int s_flags)
{
int flags = 0;
if (s_flags & MS_SYNCHRONOUS)
flags |= ST_SYNCHRONOUS;
if (s_flags & MS_MANDLOCK)
flags |= ST_MANDLOCK;
return flags;
}
static int calculate_f_flags(struct vfsmount *mnt)
{
return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
flags_by_sb(mnt->mnt_sb->s_flags);
}
static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
{
int retval;
if (!dentry->d_sb->s_op->statfs)
return -ENOSYS;
memset(buf, 0, sizeof(*buf));
retval = security_sb_statfs(dentry);
if (retval)
return retval;
retval = dentry->d_sb->s_op->statfs(dentry, buf);
if (retval == 0 && buf->f_frsize == 0)
buf->f_frsize = buf->f_bsize;
return retval;
}
int vfs_statfs(struct path *path, struct kstatfs *buf)
{
int error;
error = statfs_by_dentry(path->dentry, buf);
if (!error)
buf->f_flags = calculate_f_flags(path->mnt);
return error;
}
EXPORT_SYMBOL(vfs_statfs);
int user_statfs(const char __user *pathname, struct kstatfs *st)
{
struct path path;
int error = user_path_at(AT_FDCWD, pathname, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path);
if (!error) {
error = vfs_statfs(&path, st);
path_put(&path);
}
return error;
}
int fd_statfs(int fd, struct kstatfs *st)
{
struct fd f = fdget(fd);
int error = -EBADF;
if (f.file) {
error = vfs_statfs(&f.file->f_path, st);
fdput(f);
}
return error;
}
static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
{
struct statfs buf;
if (sizeof(buf) == sizeof(*st))
memcpy(&buf, st, sizeof(*st));
else {
if (sizeof buf.f_blocks == 4) {
if ((st->f_blocks | st->f_bfree | st->f_bavail |
st->f_bsize | st->f_frsize) &
0xffffffff00000000ULL)
return -EOVERFLOW;
/*
* f_files and f_ffree may be -1; it's okay to stuff
* that into 32 bits
*/
if (st->f_files != -1 &&
(st->f_files & 0xffffffff00000000ULL))
return -EOVERFLOW;
if (st->f_ffree != -1 &&
(st->f_ffree & 0xffffffff00000000ULL))
return -EOVERFLOW;
}
buf.f_type = st->f_type;
buf.f_bsize = st->f_bsize;
buf.f_blocks = st->f_blocks;
buf.f_bfree = st->f_bfree;
buf.f_bavail = st->f_bavail;
buf.f_files = st->f_files;
buf.f_ffree = st->f_ffree;
buf.f_fsid = st->f_fsid;
buf.f_namelen = st->f_namelen;
buf.f_frsize = st->f_frsize;
buf.f_flags = st->f_flags;
memset(buf.f_spare, 0, sizeof(buf.f_spare));
}
if (copy_to_user(p, &buf, sizeof(buf)))
return -EFAULT;
return 0;
}
static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
{
struct statfs64 buf;
if (sizeof(buf) == sizeof(*st))
memcpy(&buf, st, sizeof(*st));
else {
buf.f_type = st->f_type;
buf.f_bsize = st->f_bsize;
buf.f_blocks = st->f_blocks;
buf.f_bfree = st->f_bfree;
buf.f_bavail = st->f_bavail;
buf.f_files = st->f_files;
buf.f_ffree = st->f_ffree;
buf.f_fsid = st->f_fsid;
buf.f_namelen = st->f_namelen;
buf.f_frsize = st->f_frsize;
buf.f_flags = st->f_flags;
memset(buf.f_spare, 0, sizeof(buf.f_spare));
}
if (copy_to_user(p, &buf, sizeof(buf)))
return -EFAULT;
return 0;
}
SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
{
struct kstatfs st;
int error = user_statfs(pathname, &st);
if (!error)
error = do_statfs_native(&st, buf);
return error;
}
SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
{
struct kstatfs st;
int error;
if (sz != sizeof(*buf))
return -EINVAL;
error = user_statfs(pathname, &st);
if (!error)
error = do_statfs64(&st, buf);
return error;
}
SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
{
struct kstatfs st;
int error = fd_statfs(fd, &st);
if (!error)
error = do_statfs_native(&st, buf);
return error;
}
SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
{
struct kstatfs st;
int error;
if (sz != sizeof(*buf))
return -EINVAL;
error = fd_statfs(fd, &st);
if (!error)
error = do_statfs64(&st, buf);
return error;
}
int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
{
struct super_block *s = user_get_super(dev);
int err;
if (!s)
return -EINVAL;
err = statfs_by_dentry(s->s_root, sbuf);
drop_super(s);
return err;
}
SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
{
struct ustat tmp;
struct kstatfs sbuf;
int err = vfs_ustat(new_decode_dev(dev), &sbuf);
if (err)
return err;
memset(&tmp,0,sizeof(struct ustat));
tmp.f_tfree = sbuf.f_bfree;
tmp.f_tinode = sbuf.f_ffree;
return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
}
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