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Thunderbird Subject: Re: [PATCH 1/2] btrfs: enable cross-folio readahead for bs < ps and large folio cases To: dsterba@suse.cz, Qu Wenruo Cc: linux-btrfs@vger.kernel.org References: <4eaa4b5b1839aecd6a2bed8f995e8430fcea8ba0.1777189624.git.wqu@suse.com> <20260427132155.GJ12792@twin.jikos.cz> Content-Language: en-US From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCZxF1YAUJEP5a sQAKCRDCPZHzoSX+qF+mB/9gXu9C3BV0omDZBDWevJHxpWpOwQ8DxZEbk9b9LcrQlWdhFhyn 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compressed/regular extents. >> - * >> - * This means, if we have several sectors in the same page points to t= he same >> + * If we have several sectors in the same page points to the same >=20 > The sentence seems to be missing some words, or I don't understand > what's the meaning here. This means the situation like the following: | Folio range | | Ext A| | Ext B| Where Ext A and B are backed by the same compressed extent. In that case, if we're reading Ext A, the readahead won't work for Ext B. Thanks, Qu >=20 >> * on-disk compressed data, we will re-read the same extent many time= s and >> * this function can only help for the next page. >> */ >=20