Bug 277848 – Inconsistent Memory Management in Safari on iPhone 12 Pro

• Component: New Bugs
• Status: RESOLVED INVALID

[Davit Piloyan]

Created attachment 472094 [details]
RAM usage limitation

We have tested on iPhone 12 Pro and observed that Safari allowed approximately 1.5GB of RAM usage. Page refreshes when trying to allocate more memory. After performing a hard reset and erasing all content, I noticed that Safari allowed approximately 3GB of RAM usage for our webpage. However, after 2-3 days, the maximum allowable RAM usage in Safari decreases to about 1.5GB. Once 1.5GB limit is reached, the system reloads the page.

To further investigate, I performed another hard reset on my device, and once again, Safari allowed around 3GB of RAM usage. 

Additionally, we tested this on iPhone 15 Pro and 15 Pro Max, where the RAM limitation in Safari is consistently around 3GB (page is reloading after reaching 3GB).

Could you please clarify why the memory limit fluctuates after hard reset? Is there any specific setting or flag within Safari or iPhone that controls the maximum RAM usage, which could be causing this behavior?


I have attached a video demonstrating the scenario where Safari utilizes approximately 3GB of RAM usage.
   

I would appreciate any guidance or potential solutions to this issue. If this is a known limitation or issue, understanding the root cause would be extremely helpful.

Thank you for your attention to this matter.

Model Name: iPhone 12 Pro
iOS Version: 17.5.1
Capacity: 128gb

[Simon Fraser (smfr)]

WebContent processes on iPhone are subject to a "soft" limit of around 1.5GB; if they use more than this amount of memory, they are subject to getting killed by "jetsam".

This is a "soft" limit because these processes are allowed to go above this limit and will not be killed if memory demands from other processes are low. So what you're seeing is related to overall memory pressure on the device; after rebooting, memory pressure from other processes is low, but over time it increases at which point that 1.5G limit is respected.

What this implies is that you should design your web content to not exceed the 1.5GB limit. It will be somewhat lower on iPhone models with less RAM.

[Alexey Proskuryakov]

Marking INVALID per the above explanation.