Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-27 Thread Peter Xu
On Fri, May 27, 2022 at 12:46:31PM +0200, Ingo Molnar wrote: > > * Peter Xu wrote: > > > This patch provides a ~12% perf boost on my aarch64 test VM with a simple > > program sequentially dirtying 400MB shmem file being mmap()ed and these are > > the time it needs: > > > > Before: 650.980 ms

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-27 Thread Peter Xu
Hi, Heiko, On Fri, May 27, 2022 at 02:23:42PM +0200, Heiko Carstens wrote: > On Tue, May 24, 2022 at 07:45:31PM -0400, Peter Xu wrote: > > I observed that for each of the shared file-backed page faults, we're very > > likely to retry one more time for the 1st write fault upon no page. It's > >

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-27 Thread Heiko Carstens
On Tue, May 24, 2022 at 07:45:31PM -0400, Peter Xu wrote: > I observed that for each of the shared file-backed page faults, we're very > likely to retry one more time for the 1st write fault upon no page. It's > because we'll need to release the mmap lock for dirty rate limit purpose > with

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-27 Thread Ingo Molnar
* Peter Xu wrote: > This patch provides a ~12% perf boost on my aarch64 test VM with a simple > program sequentially dirtying 400MB shmem file being mmap()ed and these are > the time it needs: > > Before: 650.980 ms (+-1.94%) > After: 569.396 ms (+-1.38%) Nice! > arch/x86/mm/fault.c

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-26 Thread Max Filippov
On Tue, May 24, 2022 at 4:45 PM Peter Xu wrote: > > I observed that for each of the shared file-backed page faults, we're very > likely to retry one more time for the 1st write fault upon no page. It's > because we'll need to release the mmap lock for dirty rate limit purpose > with

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-26 Thread Guo Ren
For csky part. Acked-by: Guo Ren On Wed, May 25, 2022 at 7:45 AM Peter Xu wrote: > > I observed that for each of the shared file-backed page faults, we're very > likely to retry one more time for the 1st write fault upon no page. It's > because we'll need to release the mmap lock for dirty

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-25 Thread Vineet Gupta
On 5/24/22 16:45, Peter Xu wrote: I observed that for each of the shared file-backed page faults, we're very likely to retry one more time for the 1st write fault upon no page. It's because we'll need to release the mmap lock for dirty rate limit purpose with

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-25 Thread Johannes Weiner
On Tue, May 24, 2022 at 07:45:31PM -0400, Peter Xu wrote: > I observed that for each of the shared file-backed page faults, we're very > likely to retry one more time for the 1st write fault upon no page. It's > because we'll need to release the mmap lock for dirty rate limit purpose > with

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-25 Thread Peter Zijlstra
On Tue, May 24, 2022 at 07:45:31PM -0400, Peter Xu wrote: > I observed that for each of the shared file-backed page faults, we're very > likely to retry one more time for the 1st write fault upon no page. It's > because we'll need to release the mmap lock for dirty rate limit purpose > with

Re: [PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-25 Thread Geert Uytterhoeven
On Wed, May 25, 2022 at 1:45 AM Peter Xu wrote: > I observed that for each of the shared file-backed page faults, we're very > likely to retry one more time for the 1st write fault upon no page. It's > because we'll need to release the mmap lock for dirty rate limit purpose > with

[PATCH v3] mm: Avoid unnecessary page fault retires on shared memory types

2022-05-24 Thread Peter Xu
I observed that for each of the shared file-backed page faults, we're very likely to retry one more time for the 1st write fault upon no page. It's because we'll need to release the mmap lock for dirty rate limit purpose with balance_dirty_pages_ratelimited() (in fault_dirty_shared_page()). Then