In D26895#600356, @markj wrote:

So the comparison with PAGE_SIZE is arbitrary, right? There's no reason the aforementioned code could emit symbols with a value between, say, PAGE_SIZE and PAGE_SIZE * 2?

• borrow Anton's comment

I'm not an NTB expert, but LGTM.

In D26211#589162, @kib wrote:

I do not see why did not you committed the pmap.c change already. Please do, regardless of tests.

@kib Thank you for the detailed description. You practically wrote the test for me.

• add pkru_test for the fix in pmap_pkru_same()

• fix TOCTOU bug using tmpfs_pages_reserved

• CR feedback

• move init to the right place

I see the same LOR before and after the patch:

In D25312#558372, @pstef wrote:

One look at the beginning of a function definition and you have a good idea what the stack will look like. As opposed to when variables are declared somewhere later in the function.

In D25312#558466, @dab wrote:

In D25312#558449, @jhb wrote:

BTW, one thing this leaves ambiguous is [whether] you can declare variables in the middle of blocks vs at the beginning. That is:

[...]

Place declarations at the start of blocks.

I could live with this. Although I don’t have an objection to _allowing_ declarations in line when it makes sense, I do think one can get carried away and overdo it.

Long overdue. Thank you, Warner.

I was doing some more debugging in this area (on Isilon OneFS). I ran into an issue where uma_zcreate blocked (due to sx lock contention when creating sysctl oids) and bad things happened because interrupts were disabled.

• Do potentially blocking operations before disabling interrupts.
• Since I'm creating the uma zone first, allocate the initial state from it.

Hm, in some sense SSE/AVX vectors are fundamental types. 64-byte alignment is surprisingly large to me; do you know if that is that a cache-line constraint, or the size of an AVX-512 vector, or just its own special constraint? I'm just curious.

Doesn't malloc(9) align to at least sizeof(allocation) already?

In D25098#552799, @kib wrote:

I suggest to create the FPU save area as the first thing in the fpuinitstate(), and then allocate from the zone instead of manually realigning.

• review feedback