Commit f29bd2dc authored by Yann Ylavic's avatar Yann Ylavic
Browse files

core: Add ReadBufferSize, FlushMaxThreshold and FlushMaxPipelined directives. 

ReadBufferSize allows to configure the size of read buffers, for now it's
mainly used for file buckets reads (apr_bucket_file_set_buf_size), but it could
be used to replace AP_IOBUFSIZE in multiple places.

FlushMaxThreshold and FlushMaxPipelined allow to configure the hardcoded
THRESHOLD_MAX_BUFFER and MAX_REQUESTS_IN_PIPELINE from "util_filter.c".
The former sets the maximum size above which pending data are forcibly flushed
to the network (blocking eventually), and the latter sets the number of
pipelined/pending responses above which they are flushed regardless of whether
a pipelined request is immediately available (zero disables pipelining).

Larger ReadBufferSize and FlushMaxThreshold can trade memory consumption for
performances with the capacity of today's networks.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1836032 13f79535-47bb-0310-9956-ffa450edef68
parent a537a1a2

include/ap_mmn.h

+4 −1
Changes for include/ap_mmn.h: 4 added lines, 1 removed line.
Original line number Diff line number Diff line
@@ -582,6 +582,9 @@ 
 *                         ap_filter_t

 * 20180711.2 (2.5.1-dev)  Add ap_reuse_brigade_from_pool()

 * 20180716.1 (2.5.1-dev)  Axe conn_rec->empty brigade

 * 20180716.2 (2.5.1-dev)  Add read_buf_size member to core_dir_config,

 *                         flush_max_threshold and flush_max_pipelined to

 *                         core_server_config, and ap_get_read_buf_size().

 */



#define MODULE_MAGIC_COOKIE 0x41503235UL /* "AP25" */
@@ -589,7 +592,7 @@ 
#ifndef MODULE_MAGIC_NUMBER_MAJOR

#define MODULE_MAGIC_NUMBER_MAJOR 20180716

#endif

#define MODULE_MAGIC_NUMBER_MINOR 1                 /* 0...n */

#define MODULE_MAGIC_NUMBER_MINOR 2                 /* 0...n */



/**

 * Determine if the server's current MODULE_MAGIC_NUMBER is at least a

include/http_core.h

+12 −0
Changes for include/http_core.h: 12 added lines, 0 removed lines.
Original line number Diff line number Diff line
@@ -253,6 +253,13 @@ AP_DECLARE(const char *) ap_get_server_name_for_url(request_rec *r); 
 */

AP_DECLARE(apr_port_t) ap_get_server_port(const request_rec *r);



/**

 * Get the size of read buffers

 * @param r The current request

 * @return The read buffers size

 */

AP_DECLARE(apr_size_t) ap_get_read_buf_size(const request_rec *r);



/**

 * Return the limit on bytes in request msg body

 * @param r The current request
@@ -676,6 +683,8 @@ typedef struct { 


    /** Table of rules for building CGI variables, NULL if none configured */

    apr_hash_t *cgi_var_rules;



    apr_size_t read_buf_size;

} core_dir_config;



/* macro to implement off by default behaviour */
@@ -758,6 +767,9 @@ typedef struct { 
    int protocols_honor_order;

    int async_filter;

    unsigned int async_filter_set:1;

 

    apr_size_t   flush_max_threshold;

    apr_int32_t  flush_max_pipelined;

} core_server_config;



/* for AddOutputFiltersByType in core.c */

server/core.c

+105 −6
Changes for server/core.c: 105 added lines, 6 removed lines.
Original line number Diff line number Diff line
@@ -30,6 +30,11 @@ 
#include "apr_random.h"

#endif



#include "apr_version.h"

#if APR_MAJOR_VERSION < 2

#include "apu_version.h"

#endif



#define APR_WANT_IOVEC

#define APR_WANT_STRFUNC

#define APR_WANT_MEMFUNC
@@ -91,6 +96,9 @@ 
#define AP_CONTENT_MD5_ON    1

#define AP_CONTENT_MD5_UNSET 2



#define AP_FLUSH_MAX_THRESHOLD 65536

#define AP_FLUSH_MAX_PIPELINED 5



APR_HOOK_STRUCT(

    APR_HOOK_LINK(get_mgmt_items)

    APR_HOOK_LINK(insert_network_bucket)
@@ -407,6 +415,13 @@ static void *merge_core_dir_configs(apr_pool_t *a, void *basev, void *newv) 
        conf->enable_sendfile = new->enable_sendfile;

    }

 

    if (new->read_buf_size) {

        conf->read_buf_size = new->read_buf_size;

    }

    else {

        conf->read_buf_size = base->read_buf_size;

    }



    if (new->allow_encoded_slashes_set) {

        conf->allow_encoded_slashes = new->allow_encoded_slashes;

    }
@@ -482,14 +497,13 @@ static void *create_core_server_config(apr_pool_t *a, server_rec *s) 
        apr_table_setn(conf->accf_map, "http", "data");

        apr_table_setn(conf->accf_map, "https", "data");

#endif



        conf->flush_max_threshold = AP_FLUSH_MAX_THRESHOLD;

        conf->flush_max_pipelined = AP_FLUSH_MAX_PIPELINED;

    }

    /* pcalloc'ed - we have NULL's/0's

    else ** is_virtual ** {

        conf->ap_document_root = NULL;

        conf->access_name = NULL;

        conf->accf_map = NULL;

    else {

        conf->flush_max_pipelined = -1;

    }

     */



    /* initialization, no special case for global context */
@@ -593,11 +607,19 @@ static void *merge_core_server_configs(apr_pool_t *p, void *basev, void *virtv) 
    conf->protocols_honor_order = ((virt->protocols_honor_order < 0) ?

                                       base->protocols_honor_order :

                                       virt->protocols_honor_order);



    conf->async_filter = ((virt->async_filter_set) ?

                                       virt->async_filter :

                                       base->async_filter);

    conf->async_filter_set = base->async_filter_set || virt->async_filter_set;



    conf->flush_max_threshold = (virt->flush_max_threshold)

                                  ? virt->flush_max_threshold

                                  : base->flush_max_threshold;

    conf->flush_max_pipelined = (virt->flush_max_pipelined >= 0)

                                  ? virt->flush_max_pipelined

                                  : base->flush_max_pipelined;



    return conf;

}
@@ -1259,6 +1281,13 @@ AP_DECLARE(apr_off_t) ap_get_limit_req_body(const request_rec *r) 
    return d->limit_req_body;

}



AP_DECLARE(apr_size_t) ap_get_read_buf_size(const request_rec *r)

{

    core_dir_config *d = ap_get_core_module_config(r->per_dir_config);



    return d->read_buf_size ? d->read_buf_size : AP_IOBUFSIZE;

}





/*****************************************************************

 *
@@ -2285,6 +2314,65 @@ static const char *set_enable_sendfile(cmd_parms *cmd, void *d_, 
    return NULL;

}



static const char *set_read_buf_size(cmd_parms *cmd, void *d_,

                                     const char *arg)

{

    core_dir_config *d = d_;

    apr_off_t size;

    char *end;



    if (apr_strtoff(&size, arg, &end, 10)

            || size < 0 || size > APR_SIZE_MAX || *end)

        return apr_pstrcat(cmd->pool,

                           "parameter must be a number between 0 and "

                           APR_STRINGIFY(APR_SIZE_MAX) "): ",

                           arg, NULL);



    d->read_buf_size = (apr_size_t)size;



    return NULL;

}



static const char *set_flush_max_threshold(cmd_parms *cmd, void *d_,

                                           const char *arg)

{

    core_server_config *conf =

        ap_get_core_module_config(cmd->server->module_config);

    apr_off_t size;

    char *end;



    if (apr_strtoff(&size, arg, &end, 10)

            || size <= 0 || size > APR_SIZE_MAX || *end)

        return apr_pstrcat(cmd->pool,

                           "parameter must be a number between 1 and "

                           APR_STRINGIFY(APR_SIZE_MAX) "): ",

                           arg, NULL);



    conf->flush_max_threshold = (apr_size_t)size;



    return NULL;

}



static const char *set_flush_max_pipelined(cmd_parms *cmd, void *d_,

                                           const char *arg)

{

    core_server_config *conf =

        ap_get_core_module_config(cmd->server->module_config);

    apr_off_t num;

    char *end;



    if (apr_strtoff(&num, arg, &end, 10)

            || num < 0 || num > APR_INT32_MAX || *end)

        return apr_pstrcat(cmd->pool,

                           "parameter must be a number between 0 and "

                           APR_STRINGIFY(APR_INT32_MAX) ": ",

                           arg, NULL);



    conf->flush_max_pipelined = (apr_int32_t)num;



    return NULL;

}





/*

 * Report a missing-'>' syntax error.
@@ -4594,6 +4682,12 @@ AP_INIT_TAKE1("EnableMMAP", set_enable_mmap, NULL, OR_FILEINFO, 
  "Controls whether memory-mapping may be used to read files"),

AP_INIT_TAKE1("EnableSendfile", set_enable_sendfile, NULL, OR_FILEINFO,

  "Controls whether sendfile may be used to transmit files"),

AP_INIT_TAKE1("ReadBufferSize", set_read_buf_size, NULL, OR_FILEINFO,

  "Size (in bytes) of the memory buffers used to read data"),

AP_INIT_TAKE1("FlushMaxThreshold", set_flush_max_threshold, NULL, RSRC_CONF,

  "Maximum size (in bytes) above which pending data are flushed (blocking) to the network"),

AP_INIT_TAKE1("FlushMaxPipelined", set_flush_max_pipelined, NULL, RSRC_CONF,

  "Number of pipelined/pending responses above which they are flushed to the network"),



/* Old server config file commands */
@@ -5043,6 +5137,11 @@ static int default_handler(request_rec *r) 
            if (d->enable_mmap == ENABLE_MMAP_OFF) {

                (void)apr_bucket_file_enable_mmap(e, 0);

            }

#endif

#if APR_MAJOR_VERSION > 1 || (APU_MAJOR_VERSION == 1 && APU_MINOR_VERSION >= 6)

            if (d->read_buf_size) {

                apr_bucket_file_set_buf_size(e, d->read_buf_size);

            }

#endif

        }

server/util_filter.c

+13 −14
Changes for server/util_filter.c: 13 added lines, 14 removed lines.
Original line number Diff line number Diff line
@@ -33,10 +33,6 @@ 
#define FILTER_POOL     apr_hook_global_pool

#include "ap_hooks.h"   /* for apr_hook_global_pool */



/* XXX: Should these be configurable parameters? */

#define THRESHOLD_MAX_BUFFER 65536

#define MAX_REQUESTS_IN_PIPELINE 5



/*

** This macro returns true/false if a given filter should be inserted BEFORE

** another filter. This will happen when one of: 1) there isn't another
@@ -825,6 +821,7 @@ AP_DECLARE(apr_status_t) ap_filter_reinstate_brigade(ap_filter_t *f, 
    apr_size_t bytes_in_brigade, non_file_bytes_in_brigade;

    int eor_buckets_in_brigade, morphing_bucket_in_brigade;

    int loglevel = ap_get_conn_module_loglevel(f->c, APLOG_MODULE_INDEX);

    core_server_config *conf;

 

    if (loglevel >= APLOG_TRACE6) {

        ap_log_cerror(
@@ -845,16 +842,16 @@ AP_DECLARE(apr_status_t) ap_filter_reinstate_brigade(ap_filter_t *f, 
     *     of everything up that point.

     *

     *  b) The request is in CONN_STATE_HANDLER state, and the brigade

     *     contains at least THRESHOLD_MAX_BUFFER bytes in non-file

     *     contains at least flush_max_threshold bytes in non-file

     *     buckets: Do blocking writes until the amount of data in the

     *     buffer is less than THRESHOLD_MAX_BUFFER.  (The point of this

     *     buffer is less than flush_max_threshold.  (The point of this

     *     rule is to provide flow control, in case a handler is

     *     streaming out lots of data faster than the data can be

     *     sent to the client.)

     *

     *  c) The request is in CONN_STATE_HANDLER state, and the brigade

     *     contains at least MAX_REQUESTS_IN_PIPELINE EOR buckets:

     *     Do blocking writes until less than MAX_REQUESTS_IN_PIPELINE EOR

     *     contains at least flush_max_pipelined EOR buckets:

     *     Do blocking writes until less than flush_max_pipelined EOR

     *     buckets are left. (The point of this rule is to prevent too many

     *     FDs being kept open by pipelined requests, possibly allowing a

     *     DoS).
@@ -862,7 +859,7 @@ AP_DECLARE(apr_status_t) ap_filter_reinstate_brigade(ap_filter_t *f, 
     *  d) The request is being served by a connection filter and the

     *     brigade contains a morphing bucket: If there was no other

     *     reason to do a blocking write yet, try reading the bucket. If its

     *     contents fit into memory before THRESHOLD_MAX_BUFFER is reached,

     *     contents fit into memory before flush_max_threshold is reached,

     *     everything is fine. Otherwise we need to do a blocking write the

     *     up to and including the morphing bucket, because ap_save_brigade()

     *     would read the whole bucket into memory later on.
@@ -875,6 +872,8 @@ AP_DECLARE(apr_status_t) ap_filter_reinstate_brigade(ap_filter_t *f, 
    eor_buckets_in_brigade = 0;

    morphing_bucket_in_brigade = 0;



    conf = ap_get_core_module_config(f->c->base_server->module_config);



    for (bucket = APR_BRIGADE_FIRST(bb); bucket != APR_BRIGADE_SENTINEL(bb);

         bucket = next) {

        next = APR_BUCKET_NEXT(bucket);
@@ -899,18 +898,18 @@ AP_DECLARE(apr_status_t) ap_filter_reinstate_brigade(ap_filter_t *f, 
        }



        if (APR_BUCKET_IS_FLUSH(bucket)

            || non_file_bytes_in_brigade >= THRESHOLD_MAX_BUFFER

            || non_file_bytes_in_brigade >= conf->flush_max_threshold

            || (!f->r && morphing_bucket_in_brigade)

            || eor_buckets_in_brigade > MAX_REQUESTS_IN_PIPELINE) {

            || eor_buckets_in_brigade > conf->flush_max_pipelined) {

            /* this segment of the brigade MUST be sent before returning. */



            if (loglevel >= APLOG_TRACE6) {

                char *reason = APR_BUCKET_IS_FLUSH(bucket) ?

                               "FLUSH bucket" :

                               (non_file_bytes_in_brigade >= THRESHOLD_MAX_BUFFER) ?

                               "THRESHOLD_MAX_BUFFER" :

                               (non_file_bytes_in_brigade >= conf->flush_max_threshold) ?

                               "max threshold" :

                               (!f->r && morphing_bucket_in_brigade) ? "morphing bucket" :

                               "MAX_REQUESTS_IN_PIPELINE";

                               "max requests in pipeline";

                ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, f->c,

                              "will flush because of %s", reason);

                ap_log_cerror(APLOG_MARK, APLOG_TRACE8, 0, f->c,