Bug #79519 [Com]: Memory leak in PHP 7.4

Edit report at https://bugs.php.net/bug.php?id=79519&edit=1 ID: 79519 Comment by: kieran at supportpal dot com Reported by: kieran at miami-nice dot co dot uk Summary: Memory leak in PHP 7.4 Status: Open Type: Bug Package: Performance problem Operating System: Linux PHP Version: 7.4.5 Block user comment: N Private report: N New Comment: @nikita I think you're probably right: > PHP 7.4 fixed some issues related to anonymous functions "overwriting" previous > anonymous functions in the same file I "memorised" the faker requires as suggested and it cut usage from 3.8G to 2.6G. So I assume similar changes elsewhere would further reduce memory usage. The only problem is anonymous function usage is rife in Laravel! Not sure if you want to close this as duplicate of https://bugs.php.net/bug.php?id=76982 or repurpose following below comment: > The master branch case is still potentially actionable from our side. Previous Comments: ------------------------------------------------------------------------ [2020-05-15 10:58:59] nikic@php.net I see. The master branch case is still potentially actionable from our side. The problem there is that GC runs too rarely. PHP 7.4 made this worse, because collecting objects with destructors requires two GC runs, and is seems Laravel makes use of destructors somewhere in there. There's probably two things we can do to improve this at least: 1. Count any GC run with destructors as a "successful" run, so threshold is reduced. 2. Allow threshold reductions below the default of 10000, which seems too high for this case. Alternatively we could always automatically rerun GC if we encountered destructors, instead of waiting for the next GC run. ------------------------------------------------------------------------ [2020-05-15 10:53:42] kieran at supportpal dot com Can ignore the master branch. That was an issue in Laravel that I pushed a fix for. I've just not updated that repository yet. ------------------------------------------------------------------------ [2020-05-15 10:45:39] nikic@php.net It looks like the cause for the "routes" case is the same. However, the "master" branch is a different issue. Here are the massif outputs for 7.3 and 7.4: https://gist.github.com/nikic/2a5d1a6eb4a4bb82be5e18225ae16d87 ------------------------------------------------------------------------ [2020-05-15 09:22:42] nikic@php.net @kieran: PHP 7.4 fixed some issues related to anonymous functions "overwriting" previous anonymous functions in the same file under some circumstances. Unfortunately this also means that this leak is now more pronounced, because this accidental destruction vector no longer exists. ------------------------------------------------------------------------ [2020-05-15 09:16:40] kieran at supportpal dot com I thought it might be that too, but it seems odd that 7.4 is so much higher when that bug report suggests the issue exists in most of 7.x Nothing in the ms_print in my previous message? I'll check if includes can be memorised. ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=79519 -- Edit this bug report at https://bugs.php.net/bug.php?id=79519&edit=1