Lighttpd

We use mod_dirlisting to list SD card content attached to an embedded device running linux. While browsing through folders containing large amount of files (10K+) lighttpd slows down significantly and sometimes even hangs completely until being restarted.

We can see that the server is busy creating the listing with high load and - until complete - does barely respond to any other requests. Things become worse when trying to access other folders while the listing is being processed. Sometimes we can get into a state where the server does not seem to complete the listing at all and hangs from there on.

OS: Linux (embedded), kernel version 4.19.91
lighttpd version: 1.4.72

Configuration:

server.modules = (
    "mod_indexfile",
    "mod_access",
    "mod_alias",
    "mod_setenv",
    "mod_redirect",
    "mod_deflate",
    "mod_dirlisting",
    "mod_fastcgi",
    "mod_proxy",
    "mod_staticfile",
    "mod_openssl",
)
mimetype.assign   += ( 
    ".jpg"  => "image/jpeg",
    ".jpeg" => "image/jpeg",
    ".png"  => "image/png",
    ".html" => "text/html",
    ".txt"  => "text/plain",
    ".js"   => "text/javascript",
    ".svg"  => "image/svg+xml",
    ".svgz" => "image/svg+xml",
    ".css"  => "text/css" 
)
index-file.names            = ( "firstpage.html" )
url.access-deny             = ( "~", ".inc" )
static-file.exclude-extensions = ( ".php", ".pl", ".fcgi" )
deflate.cache-dir          = "/tmp/compress/" 
deflate.allowed-encodings  = ( "br", "gzip", "deflate" )
$HTTP["url"] !~ "^/(sd)/" {
    deflate.mimetypes          = ( "text/javascript", "text/css", "text/html", "text/plain" )
}
server.http-parseopts = (
    "header-strict"           => "enable",# default
    "host-strict"             => "enable",# default
    "host-normalize"          => "enable",# default
    "url-normalize-unreserved"=> "enable",# recommended highly
    "url-normalize-required"  => "enable",# recommended
    "url-ctrls-reject"        => "enable",# recommended
    "url-path-2f-decode"      => "enable",# recommended highly (unless breaks app)
    "url-path-dotseg-remove"  => "enable"# recommended highly (unless breaks app)
)
server.document-root="/home/web" 
server.upload-dirs=("/tmp")
server.errorlog="/tmp/lighttpd.log" 
server.stream-request-body=2
server.stream-response-body=2
server.chunkqueue-chunk-sz=1024
server.port=80
ssl.openssl.ssl-conf-cmd = ("Options" => "-SessionTicket")
$HTTP["url"] =~ "^/sd($|/)" {
    dir-listing.activate = "enable" 
    dir-listing.set-footer = " " 
}