2011/3/19 Jan Engelhardt <jeng...@medozas.de>: > On Saturday 2011-03-19 03:10, Lennart Poettering wrote: > >>On Fri, 18.03.11 03:44, fykc...@gmail.com (fykc...@gmail.com) wrote: >> >>> Hi all, >>> >>> Systemd hardcode page size as 4096(in macro.h), this is not always correct: >>> """ Some architectures support multiple machine types with diffenent >>> page sizes, and some machine types even support multiple page sizes >>> themselves. """ >>> >>> This patch tries to detect page size runtime by sysconf(_SC_PAGESIZE), >>> and uses 4096 as a failsafe value. Note we need memset vec to zero >>> before call mincore(src/readahead-collect.c, 129) -- if the pagesize >>> is not correct, we may randomly record wider range or more ranges to >>> readahead. >> >>Hmm, interesting. Which architecture are you using that has a page size >>!= 4K? > > sparc64 would, to name one. IA64, sparc64, powerpc, and mips, they can configure different page size(e.g. range from 4K - 32K) at kernel config time.
Changes since v1: 1. Rename get_pagesize() to page_size(), fix C99 violation, and move PAGE_ALIGN and page_size() to util.h and util.c. 2. page_size() now use static tls variable , it will call sysconf only once for each thread. 3. Remove page size related stuff from readahead-*.c/h. Note: I still keep a warning of sysconf call failure in page_size(), this may help to indicate broken sysconf implementation on some platform. (IMHO, sysconf(_SC_PAGESIZE) should never fail.) Any idea? -- Regards, - cee1
0001-Detect-page-size-runtime.patch
Description: Binary data
_______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
