Messages in this thread | | | From | "Song Bao Hua (Barry Song)" <> | Subject | RE: [PATCH 1/2] CPU, NUMA topology ABIs: clarify the overflow issue of sysfs pagebuf | Date | Thu, 29 Apr 2021 22:48:15 +0000 |
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> -----Original Message----- > From: Dave Hansen [mailto:dave.hansen@intel.com] > Sent: Friday, April 30, 2021 10:39 AM > To: Song Bao Hua (Barry Song) <song.bao.hua@hisilicon.com>; tiantao (H) > <tiantao6@hisilicon.com>; corbet@lwn.net; gregkh@linuxfoundation.org > Cc: linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; Rafael J. > Wysocki <rafael@kernel.org>; Peter Zijlstra <peterz@infradead.org>; Valentin > Schneider <valentin.schneider@arm.com>; Dave Hansen > <dave.hansen@linux.intel.com>; Daniel Bristot de Oliveira <bristot@redhat.com> > Subject: Re: [PATCH 1/2] CPU, NUMA topology ABIs: clarify the overflow issue > of sysfs pagebuf > > On 4/29/21 3:32 PM, Song Bao Hua (Barry Song) wrote: > > $ strace numactl --hardware 2>&1 | grep cpu > > openat(AT_FDCWD, "/sys/devices/system/cpu", > > O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3 > > openat(AT_FDCWD, "/sys/devices/system/node/node0/cpumap", O_RDONLY) = 3 > > openat(AT_FDCWD, "/sys/devices/system/node/node1/cpumap", O_RDONLY) = 3 > > openat(AT_FDCWD, "/sys/devices/system/node/node2/cpumap", O_RDONLY) = 3 > > openat(AT_FDCWD, "/sys/devices/system/node/node3/cpumap", O_RDONLY) = 3 > > > > If we move to binary, it means we have to change those applications. > > I thought Greg was saying to using a sysfs binary attribute using > something like like sysfs_create_bin_file(). Those don't have the > PAGE_SIZE limitation. But, there's also nothing to keep us from spewing > nice human-readable text via the "binary" file. > > We don't need to change the file format, just the internal kernel API > that we produce the files with.
Dave, thanks for clarification. Sounds a way to go.
Barry
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