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Message-ID: <474680B5.7020104@fr.ibm.com>
Date: Fri, 23 Nov 2007 08:26:45 +0100
From: Cedric Le Goater <clg@...ibm.com>
To: Pierre Peiffer <pierre.peiffer@...l.net>
CC: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
containers@...ts.osdl.org, Pavel Emelianov <xemul@...nvz.org>
Subject: Re: [PATCH 2.6.24-rc3-mm1] IPC: make struct ipc_ids static in ipc_namespace
Pierre Peiffer wrote:
>
> Each ipc_namespace contains a table of 3 pointers to struct ipc_ids (3 for
> msg, sem and shm, structure used to store all ipcs)
> These 'struct ipc_ids' are dynamically allocated for each icp_namespace as
> the ipc_namespace itself (for the init namespace, they are initialized with
> pointers to static variables instead)
>
> It is so for historical reason: in fact, before the use of idr to store the
> ipcs, the ipcs were stored in tables of variable length, depending of the
> maximum number of ipc allowed.
> Now, these 'struct ipc_ids' have a fixed size. As they are allocated in any
> cases for each new ipc_namespace, there is no gain of memory in having them
> allocated separately of the struct ipc_namespace.
>
> This patch proposes to make this table static in the struct ipc_namespace.
> Thus, we can allocate all in once and get rid of all the code needed to
> allocate and free these ipc_ids separately.
It looks safe and saves quite a lot of line.
Pavel, what do you think of it ?
Acked-by: Cedric Le Goater <clg@...ibm.com>
Thanks,
C.
> Signed-off-by: Pierre Peiffer <pierre.peiffer@...l.net>
> ---
> include/linux/ipc_namespace.h | 13 +++++++++++--
> ipc/msg.c | 26 ++++----------------------
> ipc/namespace.c | 25 ++++---------------------
> ipc/sem.c | 26 ++++----------------------
> ipc/shm.c | 26 ++++----------------------
> ipc/util.c | 6 +++---
> ipc/util.h | 16 ++++------------
> 7 files changed, 34 insertions(+), 104 deletions(-)
>
> Index: b/include/linux/ipc_namespace.h
> ===================================================================
> --- a/include/linux/ipc_namespace.h
> +++ b/include/linux/ipc_namespace.h
> @@ -2,11 +2,20 @@
> #define __IPC_NAMESPACE_H__
>
> #include <linux/err.h>
> +#include <linux/idr.h>
> +#include <linux/rwsem.h>
> +
> +struct ipc_ids {
> + int in_use;
> + unsigned short seq;
> + unsigned short seq_max;
> + struct rw_semaphore rw_mutex;
> + struct idr ipcs_idr;
> +};
>
> -struct ipc_ids;
> struct ipc_namespace {
> struct kref kref;
> - struct ipc_ids *ids[3];
> + struct ipc_ids ids[3];
>
> int sem_ctls[4];
> int used_sems;
> Index: b/ipc/msg.c
> ===================================================================
> --- a/ipc/msg.c
> +++ b/ipc/msg.c
> @@ -67,9 +67,7 @@ struct msg_sender {
> #define SEARCH_NOTEQUAL 3
> #define SEARCH_LESSEQUAL 4
>
> -static struct ipc_ids init_msg_ids;
> -
> -#define msg_ids(ns) (*((ns)->ids[IPC_MSG_IDS]))
> +#define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
>
> #define msg_unlock(msq) ipc_unlock(&(msq)->q_perm)
> #define msg_buildid(id, seq) ipc_buildid(id, seq)
> @@ -80,30 +78,17 @@ static int newque(struct ipc_namespace *
> static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
> #endif
>
> -static void __msg_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
> +void msg_init_ns(struct ipc_namespace *ns)
> {
> - ns->ids[IPC_MSG_IDS] = ids;
> ns->msg_ctlmax = MSGMAX;
> ns->msg_ctlmnb = MSGMNB;
> ns->msg_ctlmni = MSGMNI;
> atomic_set(&ns->msg_bytes, 0);
> atomic_set(&ns->msg_hdrs, 0);
> - ipc_init_ids(ids);
> + ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
> }
>
> #ifdef CONFIG_IPC_NS
> -int msg_init_ns(struct ipc_namespace *ns)
> -{
> - struct ipc_ids *ids;
> -
> - ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
> - if (ids == NULL)
> - return -ENOMEM;
> -
> - __msg_init_ns(ns, ids);
> - return 0;
> -}
> -
> void msg_exit_ns(struct ipc_namespace *ns)
> {
> struct msg_queue *msq;
> @@ -126,15 +111,12 @@ void msg_exit_ns(struct ipc_namespace *n
> }
>
> up_write(&msg_ids(ns).rw_mutex);
> -
> - kfree(ns->ids[IPC_MSG_IDS]);
> - ns->ids[IPC_MSG_IDS] = NULL;
> }
> #endif
>
> void __init msg_init(void)
> {
> - __msg_init_ns(&init_ipc_ns, &init_msg_ids);
> + msg_init_ns(&init_ipc_ns);
> ipc_init_proc_interface("sysvipc/msg",
> " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
> IPC_MSG_IDS, sysvipc_msg_proc_show);
> Index: b/ipc/namespace.c
> ===================================================================
> --- a/ipc/namespace.c
> +++ b/ipc/namespace.c
> @@ -14,35 +14,18 @@
>
> static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
> {
> - int err;
> struct ipc_namespace *ns;
>
> - err = -ENOMEM;
> ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
> if (ns == NULL)
> - goto err_mem;
> + return ERR_PTR(-ENOMEM);
>
> - err = sem_init_ns(ns);
> - if (err)
> - goto err_sem;
> - err = msg_init_ns(ns);
> - if (err)
> - goto err_msg;
> - err = shm_init_ns(ns);
> - if (err)
> - goto err_shm;
> + sem_init_ns(ns);
> + msg_init_ns(ns);
> + shm_init_ns(ns);
>
> kref_init(&ns->kref);
> return ns;
> -
> -err_shm:
> - msg_exit_ns(ns);
> -err_msg:
> - sem_exit_ns(ns);
> -err_sem:
> - kfree(ns);
> -err_mem:
> - return ERR_PTR(err);
> }
>
> struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
> Index: b/ipc/sem.c
> ===================================================================
> --- a/ipc/sem.c
> +++ b/ipc/sem.c
> @@ -87,14 +87,12 @@
> #include <asm/uaccess.h>
> #include "util.h"
>
> -#define sem_ids(ns) (*((ns)->ids[IPC_SEM_IDS]))
> +#define sem_ids(ns) ((ns)->ids[IPC_SEM_IDS])
>
> #define sem_unlock(sma) ipc_unlock(&(sma)->sem_perm)
> #define sem_checkid(sma, semid) ipc_checkid(&sma->sem_perm, semid)
> #define sem_buildid(id, seq) ipc_buildid(id, seq)
>
> -static struct ipc_ids init_sem_ids;
> -
> static int newary(struct ipc_namespace *, struct ipc_params *);
> static void freeary(struct ipc_namespace *, struct sem_array *);
> #ifdef CONFIG_PROC_FS
> @@ -118,30 +116,17 @@ static int sysvipc_sem_proc_show(struct
> #define sc_semopm sem_ctls[2]
> #define sc_semmni sem_ctls[3]
>
> -static void __sem_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
> +void sem_init_ns(struct ipc_namespace *ns)
> {
> - ns->ids[IPC_SEM_IDS] = ids;
> ns->sc_semmsl = SEMMSL;
> ns->sc_semmns = SEMMNS;
> ns->sc_semopm = SEMOPM;
> ns->sc_semmni = SEMMNI;
> ns->used_sems = 0;
> - ipc_init_ids(ids);
> + ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
> }
>
> #ifdef CONFIG_IPC_NS
> -int sem_init_ns(struct ipc_namespace *ns)
> -{
> - struct ipc_ids *ids;
> -
> - ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
> - if (ids == NULL)
> - return -ENOMEM;
> -
> - __sem_init_ns(ns, ids);
> - return 0;
> -}
> -
> void sem_exit_ns(struct ipc_namespace *ns)
> {
> struct sem_array *sma;
> @@ -163,15 +148,12 @@ void sem_exit_ns(struct ipc_namespace *n
> total++;
> }
> up_write(&sem_ids(ns).rw_mutex);
> -
> - kfree(ns->ids[IPC_SEM_IDS]);
> - ns->ids[IPC_SEM_IDS] = NULL;
> }
> #endif
>
> void __init sem_init (void)
> {
> - __sem_init_ns(&init_ipc_ns, &init_sem_ids);
> + sem_init_ns(&init_ipc_ns);
> ipc_init_proc_interface("sysvipc/sem",
> " key semid perms nsems uid gid cuid cgid otime ctime\n",
> IPC_SEM_IDS, sysvipc_sem_proc_show);
> Index: b/ipc/util.c
> ===================================================================
> --- a/ipc/util.c
> +++ b/ipc/util.c
> @@ -782,7 +782,7 @@ static void *sysvipc_proc_next(struct se
> if (ipc && ipc != SEQ_START_TOKEN)
> ipc_unlock(ipc);
>
> - return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos);
> + return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
> }
>
> /*
> @@ -795,7 +795,7 @@ static void *sysvipc_proc_start(struct s
> struct ipc_proc_iface *iface = iter->iface;
> struct ipc_ids *ids;
>
> - ids = iter->ns->ids[iface->ids];
> + ids = &iter->ns->ids[iface->ids];
>
> /*
> * Take the lock - this will be released by the corresponding
> @@ -826,7 +826,7 @@ static void sysvipc_proc_stop(struct seq
> if (ipc && ipc != SEQ_START_TOKEN)
> ipc_unlock(ipc);
>
> - ids = iter->ns->ids[iface->ids];
> + ids = &iter->ns->ids[iface->ids];
> /* Release the lock we took in start() */
> up_read(&ids->rw_mutex);
> }
> Index: b/ipc/util.h
> ===================================================================
> --- a/ipc/util.h
> +++ b/ipc/util.h
> @@ -10,7 +10,6 @@
> #ifndef _IPC_UTIL_H
> #define _IPC_UTIL_H
>
> -#include <linux/idr.h>
> #include <linux/err.h>
>
> #define USHRT_MAX 0xffff
> @@ -22,22 +21,14 @@ void shm_init (void);
>
> struct ipc_namespace;
>
> -int sem_init_ns(struct ipc_namespace *ns);
> -int msg_init_ns(struct ipc_namespace *ns);
> -int shm_init_ns(struct ipc_namespace *ns);
> +void sem_init_ns(struct ipc_namespace *ns);
> +void msg_init_ns(struct ipc_namespace *ns);
> +void shm_init_ns(struct ipc_namespace *ns);
>
> void sem_exit_ns(struct ipc_namespace *ns);
> void msg_exit_ns(struct ipc_namespace *ns);
> void shm_exit_ns(struct ipc_namespace *ns);
>
> -struct ipc_ids {
> - int in_use;
> - unsigned short seq;
> - unsigned short seq_max;
> - struct rw_semaphore rw_mutex;
> - struct idr ipcs_idr;
> -};
> -
> /*
> * Structure that holds the parameters needed by the ipc operations
> * (see after)
> @@ -68,6 +59,7 @@ struct ipc_ops {
> };
>
> struct seq_file;
> +struct ipc_ids;
>
> void ipc_init_ids(struct ipc_ids *);
> #ifdef CONFIG_PROC_FS
> Index: b/ipc/shm.c
> ===================================================================
> --- a/ipc/shm.c
> +++ b/ipc/shm.c
> @@ -56,9 +56,7 @@ struct shm_file_data {
> static const struct file_operations shm_file_operations;
> static struct vm_operations_struct shm_vm_ops;
>
> -static struct ipc_ids init_shm_ids;
> -
> -#define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS]))
> +#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
>
> #define shm_unlock(shp) \
> ipc_unlock(&(shp)->shm_perm)
> @@ -72,14 +70,13 @@ static void shm_destroy (struct ipc_name
> static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
> #endif
>
> -static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
> +void shm_init_ns(struct ipc_namespace *ns)
> {
> - ns->ids[IPC_SHM_IDS] = ids;
> ns->shm_ctlmax = SHMMAX;
> ns->shm_ctlall = SHMALL;
> ns->shm_ctlmni = SHMMNI;
> ns->shm_tot = 0;
> - ipc_init_ids(ids);
> + ipc_init_ids(&ns->ids[IPC_SHM_IDS]);
> }
>
> /*
> @@ -98,18 +95,6 @@ static void do_shm_rmid(struct ipc_names
> }
>
> #ifdef CONFIG_IPC_NS
> -int shm_init_ns(struct ipc_namespace *ns)
> -{
> - struct ipc_ids *ids;
> -
> - ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
> - if (ids == NULL)
> - return -ENOMEM;
> -
> - __shm_init_ns(ns, ids);
> - return 0;
> -}
> -
> void shm_exit_ns(struct ipc_namespace *ns)
> {
> struct shmid_kernel *shp;
> @@ -131,15 +116,12 @@ void shm_exit_ns(struct ipc_namespace *n
> total++;
> }
> up_write(&shm_ids(ns).rw_mutex);
> -
> - kfree(ns->ids[IPC_SHM_IDS]);
> - ns->ids[IPC_SHM_IDS] = NULL;
> }
> #endif
>
> void __init shm_init (void)
> {
> - __shm_init_ns(&init_ipc_ns, &init_shm_ids);
> + shm_init_ns(&init_ipc_ns);
> ipc_init_proc_interface("sysvipc/shm",
> " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
> IPC_SHM_IDS, sysvipc_shm_proc_show);
>
-
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