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improvement: should throw Lua runtime error instead of let process cr…
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…ash when no memory. (#42)

Co-authored-by: doujiang24 <dejiang@openresty.com>
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@doujiang24
doujiang24 and doujiang24 committed Sep 28, 2021
1 parent d97f37d commit a7a8b62
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Showing 4 changed files with 62 additions and 21 deletions.
32 changes: 27 additions & 5 deletions chash.c
View file
Expand Up @@ -10,6 +10,8 @@
#define u_char unsigned char
#endif

#define CHASH_OK 0
#define CHASH_ERR -1

#define crc32_final(crc) \
crc ^= 0xffffffff
Expand Down Expand Up @@ -144,7 +146,7 @@ chash_point_init(chash_point_t *arr, uint32_t base_hash, uint32_t start,
}


void
int
chash_point_sort(chash_point_t arr[], uint32_t n)
{
chash_point_t *points;
Expand All @@ -163,6 +165,9 @@ chash_point_sort(chash_point_t arr[], uint32_t n)
step = pow(2, 32) / m;

points = (chash_point_t *) calloc(m, sizeof(chash_point_t));
if (points == NULL) {
return CHASH_ERR;
}

for (i = 0; i < n; i++) {
node = &arr[i];
Expand Down Expand Up @@ -246,10 +251,12 @@ chash_point_sort(chash_point_t arr[], uint32_t n)
}

free(points);

return CHASH_OK;
}


void
int
chash_point_add(chash_point_t *old_points, uint32_t old_length,
uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id,
chash_point_t *new_points)
Expand All @@ -258,9 +265,16 @@ chash_point_add(chash_point_t *old_points, uint32_t old_length,
chash_point_t *tmp_points;

tmp_points = (chash_point_t *) calloc(num, sizeof(chash_point_t));
if (tmp_points == NULL) {
return CHASH_ERR;
}

chash_point_init_crc(tmp_points, 0, base_hash, from, num, id);
chash_point_sort(tmp_points, num);

if (chash_point_sort(tmp_points, num) != CHASH_OK) {
free(tmp_points);
return CHASH_ERR;
}

j = num - 1;
k = old_length + num - 1;
Expand All @@ -283,10 +297,12 @@ chash_point_add(chash_point_t *old_points, uint32_t old_length,
}

free(tmp_points);

return CHASH_OK;
}


void
int
chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id)
{
Expand All @@ -296,7 +312,11 @@ chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
tmp_points = (chash_point_t *) calloc(num, sizeof(chash_point_t));

chash_point_init_crc(tmp_points, 0, base_hash, from, num, id);
chash_point_sort(tmp_points, num);

if (chash_point_sort(tmp_points, num) != CHASH_OK) {
free(tmp_points);
return CHASH_ERR;
}

for (i = 0, j = 0, k = 0; i < old_length; i++) {
if (j < num
Expand All @@ -315,6 +335,8 @@ chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
}

free(tmp_points);

return CHASH_OK;
}


Expand Down
6 changes: 3 additions & 3 deletions chash.h
View file
Expand Up @@ -39,12 +39,12 @@ typedef struct {
*/
void chash_point_init(chash_point_t *points, uint32_t base_hash,
uint32_t start, uint32_t num, uint32_t id) LCH_EXPORT;
void chash_point_sort(chash_point_t *points, uint32_t npoints) LCH_EXPORT;
int chash_point_sort(chash_point_t *points, uint32_t npoints) LCH_EXPORT;

void chash_point_add(chash_point_t *old_points, uint32_t old_length,
int chash_point_add(chash_point_t *old_points, uint32_t old_length,
uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id,
chash_point_t *new_points) LCH_EXPORT;
void chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
int chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id) LCH_EXPORT;
void chash_point_delete(chash_point_t *old_points, uint32_t old_length,
uint32_t id) LCH_EXPORT;
Expand Down
44 changes: 31 additions & 13 deletions lib/resty/chash.lua
View file
Expand Up @@ -19,6 +19,10 @@ local pairs = pairs
local tostring = tostring
local tonumber = tonumber
local bxor = bit.bxor
local error = error


local CHASH_OK = 0


ffi.cdef[[
Expand All @@ -31,12 +35,12 @@ typedef struct {

void chash_point_init(chash_point_t *points, uint32_t base_hash, uint32_t start,
uint32_t num, uint32_t id);
void chash_point_sort(chash_point_t *points, uint32_t size);
int chash_point_sort(chash_point_t *points, uint32_t size);

void chash_point_add(chash_point_t *old_points, uint32_t old_length,
int chash_point_add(chash_point_t *old_points, uint32_t old_length,
uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id,
chash_point_t *new_points);
void chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
int chash_point_reduce(chash_point_t *old_points, uint32_t old_length,
uint32_t base_hash, uint32_t from, uint32_t num, uint32_t id);
void chash_point_delete(chash_point_t *old_points, uint32_t old_length,
uint32_t id);
Expand Down Expand Up @@ -117,7 +121,9 @@ local function _precompute(nodes)
start = start + num
end

clib.chash_point_sort(points, npoints)
if clib.chash_point_sort(points, npoints) ~= CHASH_OK then
error("no memory")
end

return ids, points, npoints, newnodes
end
Expand Down Expand Up @@ -194,14 +200,21 @@ local function _incr(self, id, weight)
local new_npoints = self.npoints + weight * CONSISTENT_POINTS
if self.size < new_npoints then
new_points = ffi_new(chash_point_t, new_npoints)
self.size = new_npoints
end

local base_hash = bxor(crc32(tostring(id)), 0xffffffff)
clib.chash_point_add(self.points, self.npoints, base_hash,
old_weight * CONSISTENT_POINTS,
weight * CONSISTENT_POINTS,
index, new_points)
local rc = clib.chash_point_add(self.points, self.npoints, base_hash,
old_weight * CONSISTENT_POINTS,
weight * CONSISTENT_POINTS,
index, new_points)

if rc ~= CHASH_OK then
error("no memory")
end

if self.size < new_npoints then
self.size = new_npoints
end

self.points = new_points
self.npoints = new_npoints
Expand Down Expand Up @@ -230,10 +243,15 @@ local function _decr(self, id, weight)
end

local base_hash = bxor(crc32(tostring(id)), 0xffffffff)
clib.chash_point_reduce(self.points, self.npoints, base_hash,
(old_weight - weight) * CONSISTENT_POINTS,
CONSISTENT_POINTS * weight,
index)
local from = (old_weight - weight) * CONSISTENT_POINTS
local num = CONSISTENT_POINTS * weight

local rc = clib.chash_point_reduce(self.points, self.npoints, base_hash,
from, num, index)

if rc ~= CHASH_OK then
error("no memory")
end

nodes[id] = old_weight - weight
self.npoints = self.npoints - CONSISTENT_POINTS * weight
Expand Down
1 change: 1 addition & 0 deletions lib/resty/roundrobin.lua
View file
Expand Up @@ -4,6 +4,7 @@ local next = next
local tonumber = tonumber
local setmetatable = setmetatable
local math_random = math.random
local error = error

local utils = require "resty.balancer.utils"

Expand Down

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