Messages in this thread | | | Date | Thu, 04 Apr 2013 09:35:58 +0300 | From | Adrian Hunter <> | Subject | Re: [PATCH v2] wait while adding MMC host to ensure root mounts |
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On 02/04/13 17:24, Sergey Yanovich wrote: > On Tue, 2013-04-02 at 16:36 +0300, Adrian Hunter wrote: >> On my system it is significant: >> >> Before the patch: >> >> [ 1.625623] VFS: Mounted root (ext4 filesystem) readonly on device 179:2. >> >> After the patch: >> >> [ 1.935851] VFS: Mounted root (ext4 filesystem) readonly on device 179:2. >> >> That is an addition of 310 ms which is 19% performance degradation. > > Are you sure the delay is caused by mmc?
Yes
> > On my intel laptop (userspace is Debian/unstable): > [ 1.542339] EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: (null) > ... > [ 2.735851] mmc0: new high speed SD card at address e624 > [ 2.742289] mmcblk0: mmc0:e624 SU02G 1.84 GiB > [ 2.752317] mmcblk0: p1
No, I am booting from eMMC.
> >> Please revert the patch. > > Chris, could provide a pointer on how to improve the patch? > > Maybe introduce mmc_is_hosting_root() and do something like: > > - mmc_flush_scheduled_work(); > + if (mmc_is_hosting_root()) > + mmc_flush_scheduled_work();
No, I am booting from eMMC. Perhaps a host capability:
if (host->caps2 & MMC_CAP2_ROOTWAIT) mmc_flush_scheduled_work();
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