On 17/09/2020 15:48, Matthew Wilcox wrote:
On Thu, Sep 17, 2020 at 02:01:33PM +0200, Oleg Nesterov wrote:
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If we change bio_endio to invoke the ->bi_end_io callbacks in softirq
context instead of hardirq context, we can change the pagecache to take
BH-safe locks instead of IRQ-safe locks. I believe the only reason the
lock needs to be IRQ-safe is for the benefit of paths like:
From my totally subjective experience on the filesystem side (user of
bio_endio) all HW block drivers I used including Nvme isci, sata... etc.
end up calling bio_endio in softirq. The big exception to that is the
vdX drivers under KVM. Which is very Ironic to me.
I wish we could make all drivers be uniform in this regard.
But maybe I'm just speaking crap. Its only from my limited debuging
expirience.
Thanks
Boaz
