* [PATCH] Save some bytes in mm_struct by filling holes on 64bit
@ 2008-03-12 14:28 Andi Kleen
2008-03-12 18:05 ` Andrew Morton
2008-03-13 16:40 ` Lennart Sorensen
0 siblings, 2 replies; 4+ messages in thread
From: Andi Kleen @ 2008-03-12 14:28 UTC (permalink / raw)
To: akpm, linux-kernel
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@suse.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;
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Save some bytes in mm_struct by filling holes on 64bit
2008-03-12 14:28 [PATCH] Save some bytes in mm_struct by filling holes on 64bit Andi Kleen
@ 2008-03-12 18:05 ` Andrew Morton
2008-03-12 18:38 ` Andi Kleen
2008-03-13 16:40 ` Lennart Sorensen
1 sibling, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2008-03-12 18:05 UTC (permalink / raw)
To: Andi Kleen; +Cc: linux-kernel
On Wed, 12 Mar 2008 15:28:07 +0100 Andi Kleen <ak@suse.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@suse.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?
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] Save some bytes in mm_struct by filling holes on 64bit
2008-03-12 18:05 ` Andrew Morton
@ 2008-03-12 18:38 ` Andi Kleen
0 siblings, 0 replies; 4+ messages in thread
From: Andi Kleen @ 2008-03-12 18:38 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-kernel
> The current ioctx_list_lock position is better from a cache layout POV?
Hmm ok you're right perhaps it's better to move core_waiters up
instead. Updated patch
Save some bytes in mm_struct by filling holes v2
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@suse.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 */
+ int core_waiters;
struct rw_semaphore mmap_sem;
spinlock_t page_table_lock; /* Protects page tables and some counters */
@@ -216,11 +217,10 @@ struct mm_struct {
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;
+ rwlock_t ioctx_list_lock; /* aio lock */
struct kioctx *ioctx_list;
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
struct mem_cgroup *mem_cgroup;
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Save some bytes in mm_struct by filling holes on 64bit
2008-03-12 14:28 [PATCH] Save some bytes in mm_struct by filling holes on 64bit Andi Kleen
2008-03-12 18:05 ` Andrew Morton
@ 2008-03-13 16:40 ` Lennart Sorensen
1 sibling, 0 replies; 4+ messages in thread
From: Lennart Sorensen @ 2008-03-13 16:40 UTC (permalink / raw)
To: Andi Kleen; +Cc: akpm, linux-kernel
On Wed, Mar 12, 2008 at 03:28:07PM +0100, Andi Kleen 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.
Are you going to fix the nice comments that mentioned what feature they
were part of now that things are all mixed together? I wonder if a few
bytes aren't worth paying for readable code.
After all now some 'aio bits' things are not in the 'aio bits' labeled
section.
> Signed-off-by: Andi Kleen <ak@suse.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;
> --
--
Len Sorensen
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2008-03-13 16:40 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-03-12 14:28 [PATCH] Save some bytes in mm_struct by filling holes on 64bit Andi Kleen
2008-03-12 18:05 ` Andrew Morton
2008-03-12 18:38 ` Andi Kleen
2008-03-13 16:40 ` Lennart Sorensen
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox