-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 4/16/2014 10:01 AM, Matthew Wilcox wrote: > On Tue, Apr 15, 2014 at 10:01:27PM -0400, Phillip Susi wrote: >> A lot of disk writes, especially when they are small individual >> files being written by several different processes, are hidden >> behind the flush thread. Is there no way to properly track the >> process actually responsible for the IO, even when it is the >> flush thread that initiates the writeout? > > Correct. Wow. If I understand things correctly, this also means that if process A dirties a ton of cache pages, then process B tries to write a relatively small amount, it can end up blocking in the synchronous flush path, and so it will appear that process B and flush are doing all of the writes, and not process A. That seems like a severe defect. How can such a defect be tolerated in this day and age? Why does the io accounting not track how many pages the process dirties rather than how many it actually initiates the writeout for? -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQEcBAEBAgAGBQJTTp6dAAoJEI5FoCIzSKrwBV0IAJGguGEYYWIMe0II9MtbQB1e S+ObSEygB1u6xt9GABLaUYhC7+e53vpx0/yNMbhQy+Zte79aBHXGYlP0fG4itazt 1QVjstMnSnmu6/9Q3wif3ldRgN56OkrA//L4zufLSNyWOQIRJ+I7HIg1S7ZqsvL8 Rvewat7i9jbCgT98FEqeUQp0iXqDkoZ+BVrS5s/bgBkSPdCLCiS0pRva+guabjSm B9r7n5XGrjMqRJsSGX2kofpv3sZ7NhyTBFhbryZaBe6WIChS121rFZxqAWBTqPbp Xm7N03djIekXD6Y+onLNloKV9Voe4k/1BLx1PLMjy1TRD4Cv6iTNWCB6x7ppTxM= =yp+R -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
