linux-kernel - Re: [PATCH] Save some bytes in mm_struct by filling holes on 64bit

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 12 Mar 2008 11:05:37 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Andi Kleen <ak@...e.de>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Save some bytes in mm_struct by filling holes on 64bit

On Wed, 12 Mar 2008 15:28:07 +0100 Andi Kleen <ak@...e.de> wrote:

> 
> Save some bytes in mm_struct by filling holes
> 
> Putting int values together for better packing on 64bit 
> shrinks sizeof(struct mm_struct) from 776 bytes to 760 bytes.
> 
> Signed-off-by: Andi Kleen <ak@...e.de>
> 
> Index: linux-2.6.25-rc5/include/linux/mm_types.h
> ===================================================================
> --- linux-2.6.25-rc5.orig/include/linux/mm_types.h
> +++ linux-2.6.25-rc5/include/linux/mm_types.h
> @@ -172,6 +172,7 @@ struct mm_struct {
>  	atomic_t mm_users;			/* How many users with user space? */
>  	atomic_t mm_count;			/* How many references to "struct mm_struct" (users count as 1) */
>  	int map_count;				/* number of VMAs */
> +	rwlock_t		ioctx_list_lock;	/* aio lock */
>  	struct rw_semaphore mmap_sem;
>  	spinlock_t page_table_lock;		/* Protects page tables and some counters */
>  
> @@ -213,14 +214,13 @@ struct mm_struct {
>  	unsigned int token_priority;
>  	unsigned int last_interval;
>  
> +	int core_waiters;
>  	unsigned long flags; /* Must use atomic bitops to access the bits */
>  
>  	/* coredumping support */
> -	int core_waiters;
>  	struct completion *core_startup_done, core_done;
>  
>  	/* aio bits */
> -	rwlock_t		ioctx_list_lock;
>  	struct kioctx		*ioctx_list;
>  #ifdef CONFIG_CGROUP_MEM_RES_CTLR
>  	struct mem_cgroup *mem_cgroup;

The current ioctx_list_lock position is better from a cache layout POV?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/