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new c52cddf6c8 Cleanup: memory cache lookup code (#13060)
c52cddf6c8 is described below
commit c52cddf6c8553583a163785b7e818e0574f926a6
Author: Masaori Koshiba <[email protected]>
AuthorDate: Mon Apr 13 08:28:04 2026 +0900
Cleanup: memory cache lookup code (#13060)
---
src/iocore/cache/CacheVC.cc | 62 +++++++++++++++++++++++++++------------------
1 file changed, 38 insertions(+), 24 deletions(-)
diff --git a/src/iocore/cache/CacheVC.cc b/src/iocore/cache/CacheVC.cc
index e21c7a7028..54a7abc739 100644
--- a/src/iocore/cache/CacheVC.cc
+++ b/src/iocore/cache/CacheVC.cc
@@ -69,6 +69,7 @@
namespace
{
+DbgCtl dbg_ctl_cache_ram{"cache_ram"};
DbgCtl dbg_ctl_cache_bc{"cache_bc"};
DbgCtl dbg_ctl_cache_disk_error{"cache_disk_error"};
DbgCtl dbg_ctl_cache_read{"cache_read"};
@@ -449,27 +450,56 @@ Ldone:
int
CacheVC::handleRead(int /* event ATS_UNUSED */, Event * /* e ATS_UNUSED */)
-
{
cancel_trigger();
f.doc_from_ram_cache = false;
ink_assert(stripe->mutex->thread_holding == this_ethread());
+
+ // 1. check RAM cache
if (load_from_ram_cache()) {
- goto LramHit;
- } else if (load_from_last_open_read_call()) {
- goto LmemHit;
- } else if (load_from_aggregation_buffer()) {
+ Dbg(dbg_ctl_cache_ram, "RAM cache hit");
+ f.doc_from_ram_cache = true;
+ io.aio_result = io.aiocb.aio_nbytes;
+
+ Doc *doc = reinterpret_cast<Doc *>(buf->data());
+ if (cache_config_ram_cache_compress && doc->doc_type ==
CACHE_FRAG_TYPE_HTTP && doc->hlen) {
+ SET_HANDLER(&CacheVC::handleReadDone);
+ return EVENT_RETURN;
+ }
+
+ POP_HANDLER;
+ return EVENT_RETURN;
+ }
+
+ // 2. check last open read cache
+ if (load_from_last_open_read_call()) {
+ Dbg(dbg_ctl_cache_ram, "last open read hit");
+ f.doc_from_ram_cache = true;
+ io.aio_result = io.aiocb.aio_nbytes;
+
+ POP_HANDLER;
+ return EVENT_RETURN;
+ }
+
+ // 3. check aggregation buffer
+ if (load_from_aggregation_buffer()) {
+ Dbg(dbg_ctl_cache_ram, "aggregation buffer hit");
f.doc_from_ram_cache = true;
io.aio_result = io.aiocb.aio_nbytes;
+
SET_HANDLER(&CacheVC::handleReadDone);
return EVENT_RETURN;
}
+ // 4. read from Disk (AIO) due to all memory cache miss
+ Dbg(dbg_ctl_cache_ram, "all memory cache miss");
+
ts::Metrics::Counter::increment(cache_rsb.all_mem_misses);
ts::Metrics::Counter::increment(stripe->cache_vol->vol_rsb.all_mem_misses);
+ // enqueue AIO read
io.aiocb.aio_fildes = stripe->fd;
io.aiocb.aio_offset = stripe->vol_offset(&dir);
if (static_cast<off_t>(io.aiocb.aio_offset + io.aiocb.aio_nbytes) >
static_cast<off_t>(stripe->skip + stripe->len)) {
@@ -480,30 +510,14 @@ CacheVC::handleRead(int /* event ATS_UNUSED */, Event *
/* e ATS_UNUSED */)
io.action = this;
io.thread = mutex->thread_holding->tt == DEDICATED ?
AIO_CALLBACK_THREAD_ANY : mutex->thread_holding;
SET_HANDLER(&CacheVC::handleReadDone);
- ink_assert(ink_aio_read(&io) >= 0);
-// ToDo: Why are these for debug only ??
-#if DEBUG
+ int res = ink_aio_read(&io);
+ ink_assert(res >= 0);
+
ts::Metrics::Counter::increment(cache_rsb.pread_count);
ts::Metrics::Counter::increment(stripe->cache_vol->vol_rsb.pread_count);
-#endif
return EVENT_CONT;
-
-LramHit: {
- f.doc_from_ram_cache = true;
- io.aio_result = io.aiocb.aio_nbytes;
- Doc *doc = reinterpret_cast<Doc *>(buf->data());
- if (cache_config_ram_cache_compress && doc->doc_type == CACHE_FRAG_TYPE_HTTP
&& doc->hlen) {
- SET_HANDLER(&CacheVC::handleReadDone);
- return EVENT_RETURN;
- }
-}
-LmemHit:
- f.doc_from_ram_cache = true;
- io.aio_result = io.aiocb.aio_nbytes;
- POP_HANDLER;
- return EVENT_RETURN; // allow the caller to release the volume lock
}
bool
