php-in-php: VmMemory RSS path — remove host getrusage() fallback for bootstrap self-host (#4862, #3280)

Problem

ext/standard/VmMemory.php::readRssBytes() falls back to host getrusage() when /proc/self/statm is unreadable:

if (\function_exists('getrusage')) {
    $ru = getrusage();
    ...
}

On the self-host path (native AOT binary, no Zend PHP), this either calls a host builtin during bootstrap or returns 0 silently — breaking parity for memory_get_usage(true) / memory_get_peak_usage(true) and gc_status() memory fields tracked in #3280.

Bootstrap inventory flags any function_exists('getrusage') delegation in compiler-owned paths.

php-src reference

php/php-src ext/standard/basic_functions.c — memory_get_usage, zend_memory_usage
php/php-src Zend/zend_alloc.c — emalloc counters (PHP path preferred over RSS)

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
# Host path may work; AOT binary without Zend must not call host getrusage:
grep -n getrusage ext/standard/VmMemory.php
php bin/vm.php -r "echo memory_get_usage(true), PHP_EOL;"
# After fix: same numeric semantics via /proc or emalloc table only
'

Build AOT hello-world and verify memory_get_usage(true) > 0 without host PHP installed (#1492 M3 probe).

Scope (this repo)

Path	Work
`ext/standard/VmMemory.php`	`/proc/self/statm` primary; optional `phpc_read_rss` thin ABI if needed — delete host getrusage()
`ext/standard/JitMemory.php` / `lib/JIT/Builtin/MemoryRuntime.php`	Mirror RSS source for JIT/AOT
`ext/standard/memory_get_usage.php`	Document real_usage path
Tests	Extend `test/compliance/cases/stdlib/memory_get_usage*.phpt`

Shrink C if adding ABI; prefer pure PHP /proc read already used in JIT path.

Done when

No getrusage() call from VmMemory or JIT memory helpers
memory_get_usage(true) returns non-zero RSS on Linux VM and AOT binary in Docker
php script/bootstrap-inventory.php --check shows no new host-delegation warning for VmMemory
Stdlib: MemoryUsage enum — PHP 8.4 memory_get_usage()/memory_get_peak_usage() real_usage parameter missing (ext/standard/basic_functions.stub.php) #7247 MemoryUsage enum can land on native int/enum path without host coupling

Bootstrap: memory_get_usage()/memory_get_peak_usage() — native counters without host Zend (basic_functions.c) #4862 VmMemory native path · Stdlib: memory_get_usage() / memory_get_peak_usage() / gc_status() — runtime introspection (ext/standard parity) #3280 gc_status/memory introspection · Stdlib: MemoryUsage enum — PHP 8.4 memory_get_usage()/memory_get_peak_usage() real_usage parameter missing (ext/standard/basic_functions.stub.php) #7247 MemoryUsage enum · Stdlib: getrusage() — numeric-string who + TypeError parity (ext/standard/basic_functions.c) #4600 getrusage() stdlib (separate API)

claim: PHP Runtime → PHP — starting this run (#7287: remove host getrusage() fallback from VmMemory, align VM with MemoryRuntime /proc path).

Unclaiming #7287 this run — switching to #7189 (hash_crypto_jit_runtime.c ~800 lines, primary remaining JIT C runtime). #7287 remains a quick follow-up.

claim: PHP Runtime → PHP — resuming #7287 (remove VmMemory getrusage fallback).

Remove host getrusage() fallback from VmMemory RSS path (#7287). (#7288)

Merged via PR #7288.

Change: VmMemory::readRssBytes() now reads RSS exclusively from /proc/self/statm — removed host getrusage() fallback so bootstrap/AOT binaries do not delegate to Zend PHP for memory_get_usage(true).

Verification (Docker):

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
vendor/bin/phpunit test/unit/VmMemoryTest.php
php bin/vm.php test/repro-maintainer/memory_native.php
php bin/vm.php -r "echo memory_get_usage(true), PHP_EOL;"
'

VmMemoryTest: OK (2/2)
memory_native repro: grow / peak / real
memory_get_usage(true) > 0 on Linux harness

php-in-php: drop host getrusage/posix fallbacks from VmProcess identi…

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php-in-php: VmMemory RSS path — remove host getrusage() fallback for bootstrap self-host (#4862, #3280) #7287

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php-in-php: VmMemory RSS path — remove host getrusage() fallback for bootstrap self-host (#4862, #3280) #7287

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PurHur commented on Jun 7, 2026

PurHur commented on Jun 7, 2026

PurHur commented on Jun 7, 2026

PurHur commented on Jun 7, 2026

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