From mboxrd@z Thu Jan 1 00:00:00 1970 From: Przemyslaw Marczak Date: Wed, 25 Nov 2015 14:15:13 +0100 Subject: [U-Boot] [PATCH] arm: mx6: Reduce SPL malloc pool size In-Reply-To: <201511251316.12152.marex@denx.de> References: <1448052204-4928-1-git-send-email-marex@denx.de> <201511251156.10128.marex@denx.de> <5655A2E9.70801@samsung.com> <201511251316.12152.marex@denx.de> Message-ID: <5655B461.1000801@samsung.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 11/25/2015 01:16 PM, Marek Vasut wrote: > On Wednesday, November 25, 2015 at 01:00:41 PM, Przemyslaw Marczak wrote: >> Hello Marek, >> >> On 11/25/2015 11:56 AM, Marek Vasut wrote: >>> On Wednesday, November 25, 2015 at 11:40:36 AM, Przemyslaw Marczak wrote: >>>> Hello Tim, Marek >>>> >>>> On 11/20/2015 10:40 PM, Tim Harvey wrote: >>>>> On Fri, Nov 20, 2015 at 12:43 PM, Marek Vasut wrote: >>>>>> Using 50 MiB malloc pool in SPL is nonsense. Since the caches are not >>>>>> enabled in SPL, it takes 2 seconds to init the pool and has no obvious >>>>>> benefit. Reduce the size to 1 MiB. >>>>>> >>>>>> Signed-off-by: Marek Vasut >>>>>> Cc: Stefano Babic >>>>>> Cc: Tim Harvey >>>>>> --- >>>>>> >>>>>> include/configs/imx6_spl.h | 6 +++--- >>>>>> 1 file changed, 3 insertions(+), 3 deletions(-) >>>>>> >>>>>> diff --git a/include/configs/imx6_spl.h b/include/configs/imx6_spl.h >>>>>> index 1744f2c..43ce7fe 100644 >>>>>> --- a/include/configs/imx6_spl.h >>>>>> +++ b/include/configs/imx6_spl.h >>>>>> @@ -63,15 +63,15 @@ >>>>>> >>>>>> #if defined(CONFIG_MX6SX) || defined(CONFIG_MX6UL) || >>>>>> defined(CONFIG_MX6SL) #define CONFIG_SPL_BSS_START_ADDR >>>>>> 0x88200000 >>>>>> >>>>>> -#define CONFIG_SPL_BSS_MAX_SIZE 0x100000 /* 1 MB */ >>>>>> +#define CONFIG_SPL_BSS_MAX_SIZE 0x100000 /* 1 >>>>>> MB */ >>>>>> >>>>>> #define CONFIG_SYS_SPL_MALLOC_START 0x88300000 >>>>>> >>>>>> -#define CONFIG_SYS_SPL_MALLOC_SIZE 0x3200000 /* 50 MB */ >>>>>> +#define CONFIG_SYS_SPL_MALLOC_SIZE 0x100000 /* 1 >>>>>> MB */ >>>>>> >>>>>> #define CONFIG_SYS_TEXT_BASE 0x87800000 >>>>>> #else >>>>>> #define CONFIG_SPL_BSS_START_ADDR 0x18200000 >>>>>> #define CONFIG_SPL_BSS_MAX_SIZE 0x100000 /* 1 >>>>>> MB */ #define CONFIG_SYS_SPL_MALLOC_START 0x18300000 >>>>>> >>>>>> -#define CONFIG_SYS_SPL_MALLOC_SIZE 0x3200000 /* 50 MB */ >>>>>> +#define CONFIG_SYS_SPL_MALLOC_SIZE 0x100000 /* 1 MB */ >>>>>> >>>>>> #define CONFIG_SYS_TEXT_BASE 0x17800000 >>>>>> #endif >>>>>> #endif >>>>>> >>>>>> -- >>>>>> 2.1.4 >>>>> >>>>> Acked-by: Tim Harvey >>>>> >>>>> thanks for dropping 2 secs off our time to boot! >>>>> >>>>> Tim >>>> >>>> The boot time for SPL and U-Boot can be reduced more if >>>> CONFIG_SYS_MALLOC_CLEAR_ON_INIT is unset (default is set). >>> >>> This might confuse DM, so I don't want this. DM checks if it's structures >>> were already inited and if we don't clear the malloc area, they would >>> be. >> >> DM is safe - it uses calloc() for it's structures and also driver's >> static structures are zeroed. Only some private data which is not >> allocated by DM can be risky to use. >> >> To be precise - we don't use malloc() to get pointer for zeroed memory, >> this is the job for the calloc(). >> >> So any code with bad use of malloc() should be fixed ASAP. >> >> If you assume that clear the malloc pool at boot is safe to use, then >> I'm asking you, what about the sequence malloc/free/malloc for >> potentially the same area? You can't be sure that the second returned >> pointer after calling free() - points to the initially zeroed pool. >> >> We don't clean the malloc pool for configs that we maintain and we >> didn't noticed any issues related to this. And the boot time is reduced >> significantly. > > Do you use DM in SPL ? No, we don't use the SPL - for the boards which we maintain. > > I just checked and I see it's probably only the GD which needs to be cleared > out, so we should indeed be safe. In which case, patch is welcome to enable > CONFIG_SYS_MALLOC_CLEAR_ON_INIT . > Yes I can see also for the Exynos SPL, that GD is manually cleared. But disabling the default CONFIG_SYS_MALLOC_CLEAR_ON_INIT, will help you in reducing the U-Boot init time. Just try and if you can easy measure the real difference for enable/disable this config - share the results - it can give us an interesting conclusions. Best regards, -- Przemyslaw Marczak Samsung R&D Institute Poland Samsung Electronics p.marczak at samsung.com