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file_cache: block device + discard support

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Signed-off-by: Alex Chi Z <chi@neon.tech>
This commit is contained in:
Alex Chi Z
2024-02-26 15:45:43 -05:00
parent 975786265c
commit 3ad85d917c
1 changed files with 42 additions and 1 deletions
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43
pgxn/neon/file_cache.c
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@@ -18,6 +18,10 @@
#include <sys/file.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include "neon_pgversioncompat.h"
@@ -62,6 +66,18 @@
#define SIZE_MB_TO_CHUNKS(size) ((uint32)((size) * MB / BLCKSZ / BLOCKS_PER_CHUNK))
#define BLKDISCARD _IO(0x12, 119)
int ioctl_discard(int fd, int64_t offset, int64_t len)
{
uint64_t range[2] = {(uint64_t)offset, (uint64_t)len};
int ret = ioctl(fd, BLKDISCARD, range);
if (ret < 0) {
return errno;
}
return 0;
}
typedef struct FileCacheEntry
{
BufferTag key;
@@ -91,6 +107,7 @@ static int lfc_desc = 0;
static LWLockId lfc_lock;
static int lfc_max_size;
static int lfc_size_limit;
static bool lfc_raw_block_device;
static char *lfc_path;
static FileCacheControl *lfc_ctl;
static shmem_startup_hook_type prev_shmem_startup_hook;
@@ -149,7 +166,12 @@ lfc_disable(char const *op)
* We need to use unlink to to avoid races in LFC write, because it is not
* protectedby
*/
unlink(lfc_path);
if (lfc_raw_block_device) {
ioctl_discard(lfc_desc, 0, SIZE_MB_TO_CHUNKS(lfc_max_size) * BLOCKS_PER_CHUNK * BLCKSZ);
} else {
unlink(lfc_path);
}
fd = BasicOpenFile(lfc_path, O_RDWR | O_CREAT | O_TRUNC);
if (fd < 0)
@@ -306,10 +328,18 @@ lfc_change_limit_hook(int newval, void *extra)
FileCacheEntry *victim = dlist_container(FileCacheEntry, lru_node, dlist_pop_head_node(&lfc_ctl->lru));
Assert(victim->access_count == 0);
if (lfc_raw_block_device) {
if (ioctl_discard(lfc_desc, (off_t) victim->offset * BLOCKS_PER_CHUNK * BLCKSZ, BLOCKS_PER_CHUNK * BLCKSZ) < 0) {
neon_log(LOG, "Failed to discard on raw block device: %m");
}
}
else
{
#ifdef FALLOC_FL_PUNCH_HOLE
if (fallocate(lfc_desc, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, (off_t) victim->offset * BLOCKS_PER_CHUNK * BLCKSZ, BLOCKS_PER_CHUNK * BLCKSZ) < 0)
neon_log(LOG, "Failed to punch hole in file: %m");
#endif
}
hash_search_with_hash_value(lfc_hash, &victim->key, victim->hash, HASH_REMOVE, NULL);
lfc_ctl->used -= 1;
}
@@ -359,6 +389,17 @@ lfc_init(void)
lfc_change_limit_hook,
NULL);
DefineCustomBoolVariable("neon.file_cache_raw_block_device",
"Set local file cache to raw block device mode.",
NULL,
&lfc_raw_block_device,
false, /* disabled by default */
PGC_SIGHUP,
0,
NULL,
NULL,
NULL);
DefineCustomStringVariable("neon.file_cache_path",
"Path to local file cache (can be raw device)",
NULL,