[PATCH v3 0/4] malloc: Reduce size by initializing data at runtime

[Sean Anderson]

On 10/1/23 21:16, Simon Glass wrote:
> Hi Sean,
> 
> On Thu, 28 Sept 2023 at 08:45, Sean Anderson <sean.anderson at seco.com> wrote:
>>
>> In my efforts to get SPL to fit into flash after some changes I made, I
>> noticed that av_ is one of the largest variables in SPL. As it turns
>> out, we can generate it at runtime, and the code is already there. This
>> has the potential to save 1-2k across the board, for some (very) minor
>> boot time increase.
>>
>> This series is based on [1], since this makes checking for SYS_MALLOC_F
>> easier. Passing CI at [2].
>>
>> To measure the boot time difference, I applied the following patch:
>>
>> ---
>>   common/board_r.c | 5 +++++
>>   common/spl/spl.c | 4 ++++
>>   2 files changed, 9 insertions(+)
>>
>> diff --git a/common/board_r.c b/common/board_r.c
>> index 58a5986aa54..ca624b20d46 100644
>> --- a/common/board_r.c
>> +++ b/common/board_r.c
>> @@ -194,6 +194,7 @@ static int initr_barrier(void)
>>          return 0;
>>   }
>>
>> +static ulong malloc_begin, malloc_end;
>>   static int initr_malloc(void)
>>   {
>>          ulong malloc_start;
>> @@ -208,8 +209,10 @@ static int initr_malloc(void)
>>           * reserve_noncached().
>>           */
>>          malloc_start = gd->relocaddr - TOTAL_MALLOC_LEN;
>> +       malloc_begin = timer_get_boot_us();
> 
> Perhaps this would be better done with bootstage, since then the
> timing can be enabled / disabled, and reported along with other
> timings.

I'll try that out next time.

>>          mem_malloc_init((ulong)map_sysmem(malloc_start, TOTAL_MALLOC_LEN),
>>                          TOTAL_MALLOC_LEN);
>> +       malloc_end = timer_get_boot_us();
>>          gd->flags |= GD_FLG_FULL_MALLOC_INIT;
>>          return 0;
>>   }
>> @@ -570,6 +573,8 @@ static int dm_announce(void)
>>
>>   static int run_main_loop(void)
>>   {
>> +       printf("malloc_init took %luus (%lu %lu)\n", malloc_end - malloc_begin,
>> +              malloc_begin, malloc_end);
>>   #ifdef CONFIG_SANDBOX
>>          sandbox_main_loop_init();
>>   #endif
>> diff --git a/common/spl/spl.c b/common/spl/spl.c
>> index d74acec10b5..b34d1f4b4e6 100644
>> --- a/common/spl/spl.c
>> +++ b/common/spl/spl.c
>> @@ -755,7 +755,9 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
>>          spl_set_bd();
>>
>>   #if defined(CONFIG_SYS_SPL_MALLOC)
>> +       ulong malloc_begin = timer_get_boot_us();
>>          mem_malloc_init(SYS_SPL_MALLOC_START, CONFIG_SYS_SPL_MALLOC_SIZE);
>> +       ulong malloc_end = timer_get_boot_us();
>>          gd->flags |= GD_FLG_FULL_MALLOC_INIT;
>>   #endif
>>          if (!(gd->flags & GD_FLG_SPL_INIT)) {
>> @@ -817,6 +819,8 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
>>          spl_image.boot_device = BOOT_DEVICE_NONE;
>>          board_boot_order(spl_boot_list);
>>
>> +       printf("malloc_init took %luus (%lu %lu)\n", malloc_end - malloc_begin,
>> +              malloc_begin, malloc_end);
> 
> debug() ?

Well, this is not going to be applied, so I used the easiest thing :)

--Sean

>>          ret = boot_from_devices(&spl_image, spl_boot_list,
>>                                  ARRAY_SIZE(spl_boot_list));
>>          if (ret) {
>> --
>> 2.25.1
>>
>> I found that MALLOC_CLEAR_ON_INIT dominated the mem_malloc_init time
>> (taking around 150 ms in SPL on my board). After disabling it, I found
>> that MALLOC_RUNTIME_INIT took around 5 us on average.
>>
>> [1] https://lore.kernel.org/u-boot/20230926141514.2101787-1-sjg@chromium.org/
>> [2] https://source.denx.de/u-boot/custodians/u-boot-clk/-/pipelines/17900
>>
>> Changes in v3:
>> - Use CONFIG_IS_ENABLED in conditionals
>> - Don't enable SPL_SYS_MALLOC_RUNTIME_INIT if we are short on BSS
>>
>> Changes in v2:
>> - Only mark malloc initialized after mem_malloc_init
>> - Fix cALLOc condition
>>
>> Sean Anderson (4):
>>    common: Only mark malloc initialized after mem_malloc_init
>>    malloc: Don't use ifdefs for SYS_MALLOC_DEFAULT_TO_INIT
>>    malloc: Don't statically initialize av_ if using malloc_init
>>    malloc: Enable SYS_MALLOC_RUNTIME_INIT by default in SPL
>>
>>   Kconfig           | 27 +++++++++++++++++----------
>>   common/board_r.c  |  3 ++-
>>   common/dlmalloc.c | 16 ++++++++--------
>>   3 files changed, 27 insertions(+), 19 deletions(-)
>>
>> --
>> 2.35.1.1320.gc452695387.dirty
>>
> 
> REgards,
> SImon