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

Edit report at https://bugs.php.net/bug.php?id=79519&edit=1 ID: 79519 Updated by: nikic@php.net 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: I did some work on this in https://github.com/php/php-src/pull/5593 and https://github.com/php/php-src/pull/5595, but unfortunately it's not easy to fix. Previous Comments: ------------------------------------------------------------------------ [2020-08-10 20:19:32] kieran at supportpal dot com Will there be a fix for this issue in PHP 8? Just tested against the PHP 8.0-beta.1 docker image and memory usage matches PHP 7.4 ------------------------------------------------------------------------ [2020-05-21 19:32:20] kieran at supportpal dot com @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. ------------------------------------------------------------------------ [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 ------------------------------------------------------------------------ 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