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Message-ID: <47468347.5090303@openvz.org>
Date: Fri, 23 Nov 2007 10:37:43 +0300
From: Pavel Emelyanov <xemul@...nvz.org>
To: Cedric Le Goater <clg@...ibm.com>,
Pierre Peiffer <pierre.peiffer@...l.net>
CC: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
containers@...ts.osdl.org
Subject: Re: [PATCH 2.6.24-rc3-mm1] IPC: make struct ipc_ids static in ipc_namespace
Cedric Le Goater wrote:
> 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 ?
Looks sane, good catch, Pierre.
But I'd find out whether these three ipc_ids intersect any
cache-line. In other words I'd mark the struct ipc_ids as
____cacheline_aligned and checked for any differences.
> Acked-by: Cedric Le Goater <clg@...ibm.com>
>
> Thanks,
Thanks,
Pavel
> 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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