Replace MEM_MD5_DIGEST with generic MEM_16B_BUF #1874
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... with generic 16 byte buffer.
rousskov
changed the title
| @@ -138,7 +138,7 @@ storeKeyPublicByRequestMethod(HttpRequest * request, const HttpRequestMethod& me | |||
| cache_key * | |||
| storeKeyDup(const cache_key * key) | |||
| { | |||
| cache_key *dup = (cache_key *)memAllocate(MEM_MD5_DIGEST); | |||
| cache_key *dup = (cache_key *)memAllocBuf(SQUID_MD5_DIGEST_LENGTH, nullptr); | |||
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MEM_MD5_DIGEST pool should be removed, but it should not be replaced with another pool. Instead, cache_key should not be dynamically allocated at all! The key should become a cheap-to-create/copy/compare/destroy class based on something like two uint64_t integer data members. We may even have an old TODO about this long-awaited improvement somewhere...
I am not blocking this PR on these "wrong MEM_MD5_DIGEST replacement" grounds because there may be performance value in introducing a generic 16-byte pool (as discussed elsewhere).
| @@ -310,8 +315,6 @@ Mem::Init(void) | |||
| // TODO: Carefully stop zeroing these objects memory and drop the doZero parameter | |||
| memDataInit(MEM_DREAD_CTRL, "dread_ctrl", sizeof(dread_ctrl), 0, true); | |||
| memDataInit(MEM_DWRITE_Q, "dwrite_q", sizeof(dwrite_q), 0, true); | |||
| memDataInit(MEM_MD5_DIGEST, "MD5 digest", SQUID_MD5_DIGEST_LENGTH, 0, true); | |||
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Introducing smaller generic pools may improve or harm performance. It may harm performance if we happen to have some frequently used context (e.g., in HTTP header parsing) where a short SBuf often grows from below 16 bytes to below 32 bytes -- introducing one extra memory allocation/copy. We should not make such performance-sensitive/focused changes without a pressing need and without performance testing!
I recommend keeping MEM_MD5_DIGEST pool until cache_key is upgraded (as discussed elsewhere). Instead, let's just set its doZero parameter to false so that we can make progress towards removing that pool parameter/functionality as described in the above TODO (line 310/315).
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