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X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?pl2tB4FlopVIrXwNdRJ9hgvpmJJwDK0F4hJx62DB7LT72NCri9tDKoHqsfFq?= =?us-ascii?Q?/jNFJ+Q9CauYL3lfQCbZosRobyg1e80SAhRyWs4tuPqF81p5oxFjhl5jaAeE?= =?us-ascii?Q?YMfhiQQ+oYPMFgIyxhaNIDPxRpjRbIG06BdWZDyAgB16tQf9W8noa6oeW0Vx?= =?us-ascii?Q?3ZEgZy/7h3/E0F4hWirkqb+CJzAwWy+RCHScj3QPaTyVRB95GmFI/vmdF/Jm?= =?us-ascii?Q?pTmHThm5Sr9Fkeq0r2ZZnuKwlW2hKDBfukFkycBG8UwC1+Ah9z8v4G5ewjDB?= =?us-ascii?Q?V8Lzbgq4GzvIK5np09+PU3tyriz2WHX8JzMd+FA1NSger1RN105IRiMzyNTT?= =?us-ascii?Q?S23X7JhvUFJqunmZN+0N2v3rXEWCldfsJuvbqYf1vlZPPBjdtfOBaPfSERPA?= =?us-ascii?Q?6YYwfx4fid450sZkZl21SUNgiFjPmDebntPxoOT1Z5eos5ilolU69a2pDnQY?= =?us-ascii?Q?J4G5AZLiFyT2PdMKCUe5ZKGCo63h5+z7jKCa7cld9mLmPzKedveL1vTzI1nq?= =?us-ascii?Q?hb93CVspcn2Lu2jxsCz39cT+kKL2UROERp5nUBobmZsQdxdPqldwzxdkLW7y?= =?us-ascii?Q?nSsq5b+6tErZ58NEbgItMhDxE3oBiIoXieg/zk02vn5vnrlS9PLOuUyGOODb?= =?us-ascii?Q?/QjRH3hrleBagxaH1NJs9gx32PaT5d2i7j5Ri9kW0OPHe3jl7Gt2BUFrh04G?= =?us-ascii?Q?hoH7dgtq5kPZkDy0sADNLoLoTdceRJMFqFStEKhMGSarvkxjn0/FXespz4mx?= =?us-ascii?Q?PzvwK2+8lbbLL5a9rMh96cGq7J8X8kZlUKMqgH+gAC3ifmARCd+hent6oaYx?= =?us-ascii?Q?CqrDfvDlZ6wirQo59JBOEycwR4EaniLQbyjpFGkXRi3az2e/uRuRyEjB9O2n?= =?us-ascii?Q?9CYWix5QNpBAFzrT9zsWmfkIraV3a7BgmawslL6WzCQ/dUiTPb+dkTN2J9SN?= =?us-ascii?Q?OJU2Ly8HmtwMgyqRj7Lh8n5h8TQyEt2m2F1m15yeNcM7KOCs2cjmO3mK6Uhf?= =?us-ascii?Q?Oz7gc4qDxEWFox8dA1K02sP5rvHgS/IyKSbgUDCGH4HXoswzzJ+8aXtK3f6k?= =?us-ascii?Q?/gnVLNqSwFDfs4vtdxvW/SU7zXprZ4iQfFFJ19ayjcw1AXicDONMbKxEA7yO?= =?us-ascii?Q?1x3Hh3nA3NZ4Q+f7AF+GUYIcwDnQEcmk5oV07TQNypowh/phx9kSlOLFNDfx?= =?us-ascii?Q?1fn+ssVuhJR+BmJio/he9g26XFgxtzUw3ks1hd7I1AP2Q1cbSqcL7922xsjP?= =?us-ascii?Q?lPKNRiX6Uh4bcOYDWDyzS0qDFJl6yUIycLe1rjP/lnFBLlBGL4ZbzeLuN5M7?= =?us-ascii?Q?5tJQYvBTI9D9+dzQ7+OAPszyBxoB+wC4ZFdPg3q5+Y+bag=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 97f551c6-60fb-402e-5555-08d904f83e82 X-MS-Exchange-CrossTenant-AuthSource: BYAPR15MB4136.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Apr 2021 19:04:09.8963 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Xrw5smVe7dXUvZE1PdOZlCRz6x943J2GW6z1zQwEXg49faxPdOMfomQNQjX5RFtY X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2757 X-OriginatorOrg: fb.com X-Proofpoint-ORIG-GUID: zsKqFfu2vlrkpKD6l8pikthIXJFP9HdN X-Proofpoint-GUID: zsKqFfu2vlrkpKD6l8pikthIXJFP9HdN X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-21_05:2021-04-21,2021-04-21 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 impostorscore=0 mlxscore=0 spamscore=0 malwarescore=0 bulkscore=0 phishscore=0 priorityscore=1501 clxscore=1015 suspectscore=0 adultscore=0 mlxlogscore=999 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104210130 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 21, 2021 at 06:26:37AM -0700, Shakeel Butt wrote: > On Tue, Apr 20, 2021 at 7:58 PM Roman Gushchin wrote: > > > [...] > > > > > > Michal has suggested ALLOC_OOM which is less risky. > > > > The problem is that even if you'll serve the oom daemon task with pages > > from a reserve/custom pool, it doesn't guarantee anything, because the task > > still can wait for a long time on some mutex, taken by another process, > > throttled somewhere in the reclaim. > > I am assuming here by mutex you are referring to locks which > oom-killer might have to take to read metrics or any possible lock > which oom-killer might have to take which some other process can take > too. > > Have you observed this situation happening with oomd on production? I'm not aware of any oomd-specific issues. I'm not sure if they don't exist at all, but so far it's wasn't a problem for us. Maybe it because you tend to have less pagecache (as I understand), maybe it comes to specific oomd policies/settings. I know we had different pains with mmap_sem and atop and similar programs, where reading process data stalled on mmap_sem for a long time. Thanks!