| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Mon, 29 Jul 2013 22:54:12 -0700 (PDT) From: Hugh Dickins <hughd@...gle.com> To: dmi p <d3vp0ll@...il.com> cc: linux-kernel@...r.kernel.org Subject: Re: write(2) and page cache On Sun, 28 Jul 2013, dmi p wrote: > Hi, > When I write(2) on a file such that the size of the buffer being > written is less than the page size, and the page is not in the page > cache, does the write syscall block until the page is brought into the > page cache from disk (to modify it and eventually write back), Yes (except perhaps when overwriting that part of page at end of file: I expect some filesystems might optimize out that read, and others not). > or is the page reading part async with respect to write? No, that would involve another layer of buffering, which I think would be too hard to synchronize with page cache and mmap. Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists