208683 2020-03-05 18:32:54 -0800 Delete encoded data from CachedImage once image is created 2020-05-11 16:10:57 -0700 1 1 1 Unclassified WebKit Images WebKit Nightly Build Unspecified Unspecified RESOLVED INVALID https://bugs.webkit.org/show_bug.cgi?id=207531 P2 Normal --- 1 basuke basuke basuke ysuzuki oldest_to_newest 1626435 0 basuke 2020-03-05 18:32:54 -0800 Encoded data won't be used after image is successfully created. It can be cleared. 1626482 1 392667 basuke 2020-03-05 20:42:05 -0800 Created attachment 392667 PATCH 1627868 2 basuke 2020-03-09 11:57:40 -0700 Copied from Slack conversation: https://webkit.slack.com/archives/CU64U6FDW/p1583469841216300 smfr I’m suspicious of this. doesn’t memory pressure clear the image cache, which means we’ll need to go back and decoded using the encoded data? yusukesuzuki 4 days ago Yes. Memory pressure clears the decoded data. So, we can clear the data only if (1) the decoded content can represent the entire value, and (2) the memory pressure handler does not clear it. Let’s consider about the example, Unicode source CachedScript data and it is not file-backed. This case, we are doubling the size basically because unicode string cannot be represented from SharedBuffer without decoding, and SharedBuffer needs to keep the content while it is not file backed. In this case, this is reasonable that, purging SharedBuffer and holding decoded data, and do not purge decoded data when the low memory handler happens (1) is it possible that we see many non-file backed data? (edited) A1. old Membuster is saying yes. We should measure this on new Membuster. (edited) A2. On iOS, yes. Our threshold for file backed data is very high (16KB) in iOS. (edited) basuke:beer: Ah, that make sense. Unfortunately our platform do not handle low memory situation well. That’s why I didn’t hit the case. I’ll revisit this soon after taking care of memory pressure. yusukesuzuki Right, OK. But at the same time, I believe that we should not rely on low memory handler to reduce memory usage. In the ideal world, we should have control system which attempt to shrink memory well when we are doing idle. And I (personally) believe that JSC GC could take this role (managing all the memory usage). @smfr Do you have some idea? (edited) smfr i’m not sure GC should be this thing. I’d prefer some kind of cache manger that knows about all the caches yusukesuzuki Why I would like to put this in GC is that I believe that we should attempt to make memory small even if we are using JSC framework. But it is also good that some manager can make memory shrink if this manager works well in JSC framework too. 1651506 3 basuke 2020-05-11 16:10:57 -0700 Encoded image shouldn't be deleted as Simon says. 392667 2020-03-05 20:42:05 -0800 2020-03-05 20:42:05 -0800 PATCH bug-208683.diff text/plain 1273 basuke ZGlmZiAtLWdpdCBhL1NvdXJjZS9XZWJDb3JlL0NoYW5nZUxvZyBiL1NvdXJjZS9XZWJDb3JlL0No YW5nZUxvZwppbmRleCBlY2NjOTAxMzQ2ZGQuLmQyZjAyMTEwNzk5MCAxMDA2NDQKLS0tIGEvU291 cmNlL1dlYkNvcmUvQ2hhbmdlTG9nCisrKyBiL1NvdXJjZS9XZWJDb3JlL0NoYW5nZUxvZwpAQCAt MSwzICsxLDE1IEBACisyMDIwLTAzLTA1ICBCYXN1a2UgU3V6dWtpICA8YmFzdWtlLnN1enVraUBz b255LmNvbT4KKworICAgICAgICBEZWxldGUgZW5jb2RlZCBkYXRhIGZyb20gQ2FjaGVkSW1hZ2Ug b25jZSBpbWFnZSBpcyBjcmVhdGVkCisgICAgICAgIGh0dHBzOi8vYnVncy53ZWJraXQub3JnL3No b3dfYnVnLmNnaT9pZD0yMDg2ODMKKworICAgICAgICBSZXZpZXdlZCBieSBOT0JPRFkgKE9PUFMh KS4KKworICAgICAgICBObyBiZWhhdmlvciBjaGFuZ2UuCisKKyAgICAgICAgKiBsb2FkZXIvY2Fj aGUvQ2FjaGVkSW1hZ2UuY3BwOgorICAgICAgICAoV2ViQ29yZTo6Q2FjaGVkSW1hZ2U6OmZpbmlz aExvYWRpbmcpOgorCiAyMDIwLTAzLTAyICBXZW5zb24gSHNpZWggIDx3ZW5zb25faHNpZWhAYXBw bGUuY29tPgogCiAgICAgICAgIE1ha2UgUGF0aDo6UGF0aChjb25zdCBQYXRoJikgYW5kIFBhdGg6 Om9wZXJhdG9yPShjb25zdCBQYXRoJikgY2hlYXAKZGlmZiAtLWdpdCBhL1NvdXJjZS9XZWJDb3Jl L2xvYWRlci9jYWNoZS9DYWNoZWRJbWFnZS5jcHAgYi9Tb3VyY2UvV2ViQ29yZS9sb2FkZXIvY2Fj aGUvQ2FjaGVkSW1hZ2UuY3BwCmluZGV4IGFiMDIxNTQzOTgwYS4uMjQ3ZmI4M2U2ZmM5IDEwMDY0 NAotLS0gYS9Tb3VyY2UvV2ViQ29yZS9sb2FkZXIvY2FjaGUvQ2FjaGVkSW1hZ2UuY3BwCisrKyBi L1NvdXJjZS9XZWJDb3JlL2xvYWRlci9jYWNoZS9DYWNoZWRJbWFnZS5jcHAKQEAgLTU2Myw2ICs1 NjMsMTAgQEAgdm9pZCBDYWNoZWRJbWFnZTo6ZmluaXNoTG9hZGluZyhTaGFyZWRCdWZmZXIqIGRh dGEpCiAgICAgfQogCiAgICAgRW5jb2RlZERhdGFTdGF0dXMgZW5jb2RlZERhdGFTdGF0dXMgPSB1 cGRhdGVJbWFnZURhdGEodHJ1ZSk7CisgICAgaWYgKG1fZGF0YSkgeworICAgICAgICBtX2RhdGEt PmNsZWFyKCk7CisgICAgICAgIHNldEVuY29kZWRTaXplKDApOworICAgIH0KIAogICAgIGlmIChl bmNvZGVkRGF0YVN0YXR1cyA9PSBFbmNvZGVkRGF0YVN0YXR1czo6RXJyb3IgfHwgbV9pbWFnZS0+ aXNOdWxsKCkpIHsKICAgICAgICAgLy8gSW1hZ2UgZGVjb2RpbmcgZmFpbGVkOyB0aGUgaW1hZ2Ug ZGF0YSBpcyBtYWxmb3JtZWQuCg==